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/trunk/rtl/System09_Xess_XSA-3S1000/xsasdramcntl.vhd
1,319 → 1,331
--------------------------------------------------------------------
-- Company : XESS Corp.
-- Engineer : Dave Vanden Bout
-- Creation Date : 05/17/2005
-- Copyright : 2005, XESS Corp
-- Tool Versions : WebPACK 6.3.03i
--
-- Description:
-- Customizes the generic SDRAM controller module for the XSA Board.
--
-- Revision:
-- 1.1.0
--
-- Additional Comments:
-- 1.1.0:
-- Added CLK_DIV generic parameter to allow stepping-down the clock frequency.
-- Added MULTIPLE_ACTIVE_ROWS generic parameter to enable/disable keeping an active row in each bank.
-- 1.0.0:
-- Initial release.
--
-- License:
-- This code can be freely distributed and modified as long as
-- this header is not removed.
--------------------------------------------------------------------
 
 
 
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use UNISIM.VComponents.all;
use WORK.common.all;
use WORK.sdram.all;
 
 
package XSASDRAM is
 
component XSASDRAMCntl
generic(
FREQ : natural := 100_000; -- operating frequency in KHz
CLK_DIV : real := 2.0; -- divisor for FREQ (can only be 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 8.0 or 16.0)
PIPE_EN : boolean := false; -- if true, enable pipelined read operations
MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
DATA_WIDTH : natural := 16; -- host & SDRAM data width
NROWS : natural := 8096; -- number of rows in SDRAM array
NCOLS : natural := 512; -- number of columns in SDRAM array
HADDR_WIDTH : natural := 24; -- host-side address width
SADDR_WIDTH : natural := 13 -- SDRAM-side address width
);
port(
-- host side
clk : in std_logic; -- master clock
bufclk : out std_logic; -- buffered master clock
clk1x : out std_logic; -- host clock sync'ed to master clock (and divided if CLK_DIV>1)
clk2x : out std_logic; -- double-speed host clock
lock : out std_logic; -- true when host clock is locked to master clock
rst : in std_logic; -- reset
rd : in std_logic; -- initiate read operation
wr : in std_logic; -- initiate write operation
earlyOpBegun : out std_logic; -- read/write/self-refresh op begun (async)
opBegun : out std_logic; -- read/write/self-refresh op begun (clocked)
rdPending : out std_logic; -- read operation(s) are still in the pipeline
done : out std_logic; -- read or write operation is done
rdDone : out std_logic; -- read done and data is available
hAddr : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host
hDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host
hDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data to host
status : out std_logic_vector(3 downto 0); -- diagnostic status of the FSM
 
-- SDRAM side
sclkfb : in std_logic; -- clock from SDRAM after PCB delays
sclk : out std_logic; -- SDRAM clock sync'ed to master clock
cke : out std_logic; -- clock-enable to SDRAM
cs_n : out std_logic; -- chip-select to SDRAM
ras_n : out std_logic; -- SDRAM row address strobe
cas_n : out std_logic; -- SDRAM column address strobe
we_n : out std_logic; -- SDRAM write enable
ba : out std_logic_vector(1 downto 0); -- SDRAM bank address bits
sAddr : out std_logic_vector(SADDR_WIDTH-1 downto 0); -- SDRAM row/column address
sData : inout std_logic_vector(DATA_WIDTH-1 downto 0); -- SDRAM in/out databus
dqmh : out std_logic; -- high databits I/O mask
dqml : out std_logic -- low databits I/O mask
);
end component;
 
end package XSASDRAM;
 
 
 
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use UNISIM.VComponents.all;
use WORK.common.all;
use WORK.sdram.all;
 
entity XSASDRAMCntl is
generic(
FREQ : natural := 100_000; -- operating frequency in KHz
CLK_DIV : real := 2.0; -- divisor for FREQ (can only be 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 8.0 or 16.0)
PIPE_EN : boolean := false; -- if true, enable pipelined read operations
MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
DATA_WIDTH : natural := 16; -- host & SDRAM data width
NROWS : natural := 8192; -- number of rows in SDRAM array
NCOLS : natural := 512; -- number of columns in SDRAM array
HADDR_WIDTH : natural := 24; -- host-side address width
SADDR_WIDTH : natural := 13 -- SDRAM-side address width
);
port(
-- host side
clk : in std_logic; -- master clock
bufclk : out std_logic; -- buffered master clock
clk1x : out std_logic; -- host clock sync'ed to master clock (and divided if CLK_DIV>1)
clk2x : out std_logic; -- double-speed host clock
lock : out std_logic; -- true when host clock is locked to master clock
rst : in std_logic; -- reset
rd : in std_logic; -- initiate read operation
wr : in std_logic; -- initiate write operation
earlyOpBegun : out std_logic; -- read/write/self-refresh op begun (async)
opBegun : out std_logic; -- read/write/self-refresh op begun (clocked)
rdPending : out std_logic; -- read operation(s) are still in the pipeline
done : out std_logic; -- read or write operation is done
rdDone : out std_logic; -- read done and data is available
hAddr : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host
hDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host
hDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data to host
status : out std_logic_vector(3 downto 0); -- diagnostic status of the FSM
 
-- SDRAM side
sclkfb : in std_logic; -- clock from SDRAM after PCB delays
sclk : out std_logic; -- SDRAM clock sync'ed to master clock
cke : out std_logic; -- clock-enable to SDRAM
cs_n : out std_logic; -- chip-select to SDRAM
ras_n : out std_logic; -- SDRAM row address strobe
cas_n : out std_logic; -- SDRAM column address strobe
we_n : out std_logic; -- SDRAM write enable
ba : out std_logic_vector(1 downto 0); -- SDRAM bank address bits
sAddr : out std_logic_vector(SADDR_WIDTH-1 downto 0); -- SDRAM row/column address
sData : inout std_logic_vector(DATA_WIDTH-1 downto 0); -- SDRAM in/out databus
dqmh : out std_logic; -- high databits I/O mask
dqml : out std_logic -- low databits I/O mask
);
end XSASDRAMCntl;
 
 
 
architecture arch of XSASDRAMCntl is
 
-- The SDRAM controller and external SDRAM chip will clock on the same edge
-- if the frequency and divided frequency are both greater than the minimum DLL lock frequency.
-- Otherwise the DLLs cannot be used so the SDRAM controller and external SDRAM clock on opposite edges
-- to try and mitigate the clock skew between the internal FPGA logic and the external SDRAM.
constant MIN_LOCK_FREQ : real := 25_000.0;
constant IN_PHASE : boolean := real(FREQ)/CLK_DIV >= MIN_LOCK_FREQ;
-- Calculate the frequency of the clock for the SDRAM.
constant SDRAM_FREQ : natural := int_select(IN_PHASE, (FREQ*integer(2.0*CLK_DIV))/2, FREQ);
-- Compute the CLKDV_DIVIDE generic paramter for the DLL modules. It defaults to 2 when CLK_DIV=1
-- because the DLL does not support a divisor of 1 on the CLKDV output. We use the CLK0 output
-- when CLK_DIV=1 so we don't care what is output on thr CLK_DIV output of the DLL.
constant CLKDV_DIVIDE : real := real_select(CLK_DIV = 1.0, 2.0, CLK_DIV);
 
signal int_clkin, -- signals for internal logic clock DLL
int_clk1x, int_clk1x_b,
int_clk2x, int_clk2x_b,
int_clkdv, int_clkdv_b : std_logic;
signal ext_clkin, sclkfb_b, ext_clk1x : std_logic; -- signals for external logic clock DLL
signal dllext_rst, dllext_rst_n : std_logic; -- external DLL reset signal
signal clk_i : std_logic; -- clock for SDRAM controller logic
signal int_lock, ext_lock, lock_i : std_logic; -- DLL lock signals
 
-- bus for holding output data from SDRAM
signal sDOut : std_logic_vector(sData'range);
signal sDOutEn : std_logic;
 
begin
 
-----------------------------------------------------------
-- setup the DLLs for clock generation
-----------------------------------------------------------
 
-- master clock must come from a dedicated clock pin
clkin : IBUFG port map (I => clk, O => int_clkin);
 
-- The external DLL is driven from the same source as the internal DLL
-- if the clock divisor is 1. If CLK_DIV is greater than 1, then the external DLL
-- is driven by the divided clock from the internal DLL. Otherwise, the SDRAM will be
-- clocked on the opposite edge if the internal and external logic are not in-phase.
ext_clkin <= int_clkin when (IN_PHASE and (CLK_DIV = 1.0)) else
int_clkdv_b when (IN_PHASE and (CLK_DIV/=1.0)) else
not int_clkin;
 
-- Generate the DLLs for sync'ing the clocks as long as the clocks
-- have a frequency high enough for the DLLs to lock
gen_dlls : if IN_PHASE generate
 
-- generate an internal clock sync'ed to the master clock
dllint : CLKDLL
generic map(
CLKDV_DIVIDE => CLKDV_DIVIDE
)
port map(
CLKIN => int_clkin,
CLKFB => int_clk1x_b,
CLK0 => int_clk1x,
RST => ZERO,
CLK90 => open,
CLK180 => open,
CLK270 => open,
CLK2X => int_clk2x,
CLKDV => int_clkdv,
LOCKED => int_lock
);
 
-- sync'ed single, doubled and divided clocks for use by internal logic
int_clk1x_buf : BUFG port map(I => int_clk1x, O => int_clk1x_b);
int_clk2x_buf : BUFG port map(I => int_clk2x, O => int_clk2x_b);
int_clkdv_buf : BUFG port map(I => int_clkdv, O => int_clkdv_b);
 
-- The external DLL is held in a reset state until the internal DLL locks.
-- Then the external DLL reset is released after a delay set by this shift register.
-- This keeps the external DLL from locking onto the internal DLL clock signal
-- until it is stable.
SRL16_inst : SRL16
generic map (
INIT => X"0000"
)
port map (
CLK => clk_i,
A0 => '1',
A1 => '1',
A2 => '1',
A3 => '1',
D => int_lock,
Q => dllext_rst_n
);
dllext_rst <= not dllext_rst when CLK_DIV/=1.0 else ZERO;
 
-- generate an external SDRAM clock sync'ed to the master clock
sclkfb_buf : IBUFG port map(I => sclkfb, O => sclkfb_b); -- SDRAM clock with PCB delays
-- sclkfb_buf : BUFGMUX port map(I => sclkfb, O => sclkfb_b); -- SDRAM clock with PCB delays
dllext : CLKDLL port map(
CLKIN => ext_clkin, -- this is either the master clock or the divided clock from the internal DLL
CLKFB => sclkfb_b,
CLK0 => ext_clk1x,
RST => dllext_rst,
CLK90 => open,
CLK180 => open,
CLK270 => open,
CLK2X => open,
CLKDV => open,
LOCKED => ext_lock
);
 
end generate;
 
-- The buffered clock is just a buffered version of the master clock.
bufclk <= int_clkin;
-- The host-side clock comes from the CLK0 output of the internal DLL if the clock divisor is 1.
-- Otherwise it comes from the CLKDV output if the clock divisor is greater than 1.
-- Otherwise it is just a copy of the master clock if the DLLs aren't being used.
clk_i <= int_clk1x_b when (IN_PHASE and (CLK_DIV = 1.0)) else
int_clkdv_b when (IN_PHASE and (CLK_DIV/=1.0)) else
int_clkin;
clk1x <= clk_i; -- This is the output of the host-side clock
clk2x <= int_clk2x_b when IN_PHASE else int_clkin; -- this is the doubled master clock
sclk <= ext_clk1x when IN_PHASE else ext_clkin; -- this is the clock for the external SDRAM
 
-- indicate the lock status of the internal and external DLL
lock_i <= int_lock and ext_lock when IN_PHASE else YES;
lock <= lock_i; -- lock signal for the host logic
 
-- SDRAM memory controller module
u1 : sdramCntl
generic map(
FREQ => SDRAM_FREQ,
IN_PHASE => IN_PHASE,
PIPE_EN => PIPE_EN,
MAX_NOP => MAX_NOP,
MULTIPLE_ACTIVE_ROWS => MULTIPLE_ACTIVE_ROWS,
DATA_WIDTH => DATA_WIDTH,
NROWS => NROWS,
NCOLS => NCOLS,
HADDR_WIDTH => HADDR_WIDTH,
SADDR_WIDTH => SADDR_WIDTH
)
port map(
clk => clk_i, -- master clock from external clock source (unbuffered)
lock => lock_i, -- valid synchronized clocks indicator
rst => rst, -- reset
rd => rd, -- host-side SDRAM read control from memory tester
wr => wr, -- host-side SDRAM write control from memory tester
rdPending => rdPending,
opBegun => opBegun, -- SDRAM memory read/write done indicator
earlyOpBegun => earlyOpBegun, -- SDRAM memory read/write done indicator
rdDone => rdDone, -- SDRAM memory read/write done indicator
done => done,
hAddr => hAddr, -- host-side address from memory tester
hDIn => hDIn, -- test data pattern from memory tester
hDOut => hDOut, -- SDRAM data output to memory tester
status => status, -- SDRAM controller state (for diagnostics)
cke => cke, -- SDRAM clock enable
ce_n => cs_n, -- SDRAM chip-select
ras_n => ras_n, -- SDRAM RAS
cas_n => cas_n, -- SDRAM CAS
we_n => we_n, -- SDRAM write-enable
ba => ba, -- SDRAM bank address
sAddr => sAddr, -- SDRAM address
sDIn => sData, -- input data from SDRAM
sDOut => sDOut, -- output data to SDRAM
sDOutEn => sDOutEn, -- enable drivers to send data to SDRAM
dqmh => dqmh, -- SDRAM DQMH
dqml => dqml -- SDRAM DQML
);
 
sData <= sDOut when sDOutEn = YES else (others => 'Z');
 
end arch;
--------------------------------------------------------------------
-- Company : XESS Corp.
-- Engineer : Dave Vanden Bout
-- Creation Date : 05/17/2005
-- Copyright : 2005, XESS Corp
-- Tool Versions : WebPACK 6.3.03i
--
-- Description:
-- Customizes the generic SDRAM controller module for the XSA Board.
--
-- Revision:
-- 1.2.0
--
-- Additional Comments:
-- 1.2.0:
-- added upper and lower data strobe signals
-- John Kent 2008-03-23
-- 1.1.0:
-- Added CLK_DIV generic parameter to allow stepping-down the clock frequency.
-- Added MULTIPLE_ACTIVE_ROWS generic parameter to enable/disable keeping an active row in each bank.
-- 1.0.0:
-- Initial release.
--
-- License:
-- This code can be freely distributed and modified as long as
-- this header is not removed.
--------------------------------------------------------------------
 
 
 
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use UNISIM.VComponents.all;
use WORK.common.all;
use WORK.sdram.all;
 
 
package XSASDRAM is
 
component XSASDRAMCntl
generic(
FREQ : natural := 100_000; -- operating frequency in KHz
CLK_DIV : real := 2.0; -- divisor for FREQ (can only be 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 8.0 or 16.0)
PIPE_EN : boolean := false; -- if true, enable pipelined read operations
MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
DATA_WIDTH : natural := 16; -- host & SDRAM data width
NROWS : natural := 8096; -- number of rows in SDRAM array
NCOLS : natural := 512; -- number of columns in SDRAM array
HADDR_WIDTH : natural := 24; -- host-side address width
SADDR_WIDTH : natural := 13 -- SDRAM-side address width
);
port(
-- host side
clk : in std_logic; -- master clock
bufclk : out std_logic; -- buffered master clock
clk1x : out std_logic; -- host clock sync'ed to master clock (and divided if CLK_DIV>1)
clk2x : out std_logic; -- double-speed host clock
lock : out std_logic; -- true when host clock is locked to master clock
rst : in std_logic; -- reset
rd : in std_logic; -- initiate read operation
wr : in std_logic; -- initiate write operation
uds : in std_logic; -- upper data strobe
lds : in std_logic; -- lower data strobe
earlyOpBegun : out std_logic; -- read/write/self-refresh op begun (async)
opBegun : out std_logic; -- read/write/self-refresh op begun (clocked)
rdPending : out std_logic; -- read operation(s) are still in the pipeline
done : out std_logic; -- read or write operation is done
rdDone : out std_logic; -- read done and data is available
hAddr : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host
hDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host
hDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data to host
status : out std_logic_vector(3 downto 0); -- diagnostic status of the FSM
 
-- SDRAM side
sclkfb : in std_logic; -- clock from SDRAM after PCB delays
sclk : out std_logic; -- SDRAM clock sync'ed to master clock
cke : out std_logic; -- clock-enable to SDRAM
cs_n : out std_logic; -- chip-select to SDRAM
ras_n : out std_logic; -- SDRAM row address strobe
cas_n : out std_logic; -- SDRAM column address strobe
we_n : out std_logic; -- SDRAM write enable
ba : out std_logic_vector(1 downto 0); -- SDRAM bank address bits
sAddr : out std_logic_vector(SADDR_WIDTH-1 downto 0); -- SDRAM row/column address
sData : inout std_logic_vector(DATA_WIDTH-1 downto 0); -- SDRAM in/out databus
dqmh : out std_logic; -- high databits I/O mask
dqml : out std_logic -- low databits I/O mask
);
end component;
 
end package XSASDRAM;
 
 
 
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use UNISIM.VComponents.all;
use WORK.common.all;
use WORK.sdram.all;
 
entity XSASDRAMCntl is
generic(
FREQ : natural := 100_000; -- operating frequency in KHz
CLK_DIV : real := 2.0; -- divisor for FREQ (can only be 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 8.0 or 16.0)
PIPE_EN : boolean := false; -- if true, enable pipelined read operations
MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
DATA_WIDTH : natural := 16; -- host & SDRAM data width
NROWS : natural := 8192; -- number of rows in SDRAM array
NCOLS : natural := 512; -- number of columns in SDRAM array
HADDR_WIDTH : natural := 24; -- host-side address width
SADDR_WIDTH : natural := 13 -- SDRAM-side address width
);
port(
-- host side
clk : in std_logic; -- master clock
bufclk : out std_logic; -- buffered master clock
clk1x : out std_logic; -- host clock sync'ed to master clock (and divided if CLK_DIV>1)
clk2x : out std_logic; -- double-speed host clock
lock : out std_logic; -- true when host clock is locked to master clock
rst : in std_logic; -- reset
rd : in std_logic; -- initiate read operation
wr : in std_logic; -- initiate write operation
uds : in std_logic; -- upper data strobe
lds : in std_logic; -- lower data strobe
earlyOpBegun : out std_logic; -- read/write/self-refresh op begun (async)
opBegun : out std_logic; -- read/write/self-refresh op begun (clocked)
rdPending : out std_logic; -- read operation(s) are still in the pipeline
done : out std_logic; -- read or write operation is done
rdDone : out std_logic; -- read done and data is available
hAddr : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host
hDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host
hDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data to host
status : out std_logic_vector(3 downto 0); -- diagnostic status of the FSM
 
-- SDRAM side
sclkfb : in std_logic; -- clock from SDRAM after PCB delays
sclk : out std_logic; -- SDRAM clock sync'ed to master clock
cke : out std_logic; -- clock-enable to SDRAM
cs_n : out std_logic; -- chip-select to SDRAM
ras_n : out std_logic; -- SDRAM row address strobe
cas_n : out std_logic; -- SDRAM column address strobe
we_n : out std_logic; -- SDRAM write enable
ba : out std_logic_vector(1 downto 0); -- SDRAM bank address bits
sAddr : out std_logic_vector(SADDR_WIDTH-1 downto 0); -- SDRAM row/column address
sData : inout std_logic_vector(DATA_WIDTH-1 downto 0); -- SDRAM in/out databus
dqmh : out std_logic; -- high databits I/O mask
dqml : out std_logic -- low databits I/O mask
);
end XSASDRAMCntl;
 
 
 
architecture arch of XSASDRAMCntl is
 
-- The SDRAM controller and external SDRAM chip will clock on the same edge
-- if the frequency and divided frequency are both greater than the minimum DLL lock frequency.
-- Otherwise the DLLs cannot be used so the SDRAM controller and external SDRAM clock on opposite edges
-- to try and mitigate the clock skew between the internal FPGA logic and the external SDRAM.
constant MIN_LOCK_FREQ : real := 25_000.0;
constant IN_PHASE : boolean := real(FREQ)/CLK_DIV >= MIN_LOCK_FREQ;
-- Calculate the frequency of the clock for the SDRAM.
-- constant SDRAM_FREQ : natural := int_select(IN_PHASE, (FREQ*integer(2.0*CLK_DIV))/2, FREQ);
constant SDRAM_FREQ : natural := int_select(IN_PHASE, (FREQ*2)/integer(2.0*CLK_DIV), FREQ);
-- Compute the CLKDV_DIVIDE generic paramter for the DLL modules. It defaults to 2 when CLK_DIV=1
-- because the DLL does not support a divisor of 1 on the CLKDV output. We use the CLK0 output
-- when CLK_DIV=1 so we don't care what is output on thr CLK_DIV output of the DLL.
constant CLKDV_DIVIDE : real := real_select(CLK_DIV = 1.0, 2.0, CLK_DIV);
 
signal int_clkin, -- signals for internal logic clock DLL
int_clk1x, int_clk1x_b,
int_clk2x, int_clk2x_b,
int_clkdv, int_clkdv_b : std_logic;
signal ext_clkin, sclkfb_b, ext_clk1x : std_logic; -- signals for external logic clock DLL
signal dllext_rst, dllext_rst_n : std_logic; -- external DLL reset signal
signal clk_i : std_logic; -- clock for SDRAM controller logic
signal int_lock, ext_lock, lock_i : std_logic; -- DLL lock signals
 
-- bus for holding output data from SDRAM
signal sDOut : std_logic_vector(sData'range);
signal sDOutEn : std_logic;
 
begin
 
-----------------------------------------------------------
-- setup the DLLs for clock generation
-----------------------------------------------------------
 
-- master clock must come from a dedicated clock pin
clkin_buf : BUFG port map (I => clk, O => int_clkin);
 
-- The external DLL is driven from the same source as the internal DLL
-- if the clock divisor is 1. If CLK_DIV is greater than 1, then the external DLL
-- is driven by the divided clock from the internal DLL. Otherwise, the SDRAM will be
-- clocked on the opposite edge if the internal and external logic are not in-phase.
ext_clkin <= int_clkin when (IN_PHASE and (CLK_DIV = 1.0)) else
int_clkdv_b when (IN_PHASE and (CLK_DIV/=1.0)) else
not int_clkin;
 
-- Generate the DLLs for sync'ing the clocks as long as the clocks
-- have a frequency high enough for the DLLs to lock
gen_dlls : if IN_PHASE generate
 
-- generate an internal clock sync'ed to the master clock
dllint : CLKDLL
generic map(
CLKDV_DIVIDE => CLKDV_DIVIDE
)
port map(
CLKIN => int_clkin,
CLKFB => int_clk1x_b,
CLK0 => int_clk1x,
RST => ZERO,
CLK90 => open,
CLK180 => open,
CLK270 => open,
CLK2X => int_clk2x,
CLKDV => int_clkdv,
LOCKED => int_lock
);
 
-- sync'ed single, doubled and divided clocks for use by internal logic
int_clk1x_buf : BUFG port map(I => int_clk1x, O => int_clk1x_b);
int_clk2x_buf : BUFG port map(I => int_clk2x, O => int_clk2x_b);
int_clkdv_buf : BUFG port map(I => int_clkdv, O => int_clkdv_b);
 
-- The external DLL is held in a reset state until the internal DLL locks.
-- Then the external DLL reset is released after a delay set by this shift register.
-- This keeps the external DLL from locking onto the internal DLL clock signal
-- until it is stable.
SRL16_inst : SRL16
generic map (
INIT => X"0000"
)
port map (
CLK => clk_i,
A0 => '1',
A1 => '1',
A2 => '1',
A3 => '1',
D => int_lock,
Q => dllext_rst_n
);
-- Error ???
-- dllext_rst <= not dllext_rst when CLK_DIV/=1.0 else ZERO;
dllext_rst <= not dllext_rst_n when CLK_DIV/=1.0 else ZERO;
 
-- generate an external SDRAM clock sync'ed to the master clock
sclkfb_buf : IBUFG port map(I => sclkfb, O => sclkfb_b); -- SDRAM clock with PCB delays
 
dllext : CLKDLL port map(
CLKIN => ext_clkin, -- this is either the master clock or the divided clock from the internal DLL
CLKFB => sclkfb_b,
CLK0 => ext_clk1x,
RST => dllext_rst,
CLK90 => open,
CLK180 => open,
CLK270 => open,
CLK2X => open,
CLKDV => open,
LOCKED => ext_lock
);
 
end generate;
 
-- The buffered clock is just a buffered version of the master clock.
bufclk_bufg : BUFG port map (I => int_clkin, O => bufclk);
-- The host-side clock comes from the CLK0 output of the internal DLL if the clock divisor is 1.
-- Otherwise it comes from the CLKDV output if the clock divisor is greater than 1.
-- Otherwise it is just a copy of the master clock if the DLLs aren't being used.
clk_i <= int_clk1x_b when (IN_PHASE and (CLK_DIV = 1.0)) else
int_clkdv_b when (IN_PHASE and (CLK_DIV/=1.0)) else
int_clkin;
clk1x <= clk_i; -- This is the output of the host-side clock
clk2x <= int_clk2x_b when IN_PHASE else int_clkin; -- this is the doubled master clock
sclk <= ext_clk1x when IN_PHASE else ext_clkin; -- this is the clock for the external SDRAM
 
-- indicate the lock status of the internal and external DLL
lock_i <= int_lock and ext_lock when IN_PHASE else YES;
lock <= lock_i; -- lock signal for the host logic
 
-- SDRAM memory controller module
u1 : sdramCntl
generic map(
FREQ => SDRAM_FREQ,
IN_PHASE => IN_PHASE,
PIPE_EN => PIPE_EN,
MAX_NOP => MAX_NOP,
MULTIPLE_ACTIVE_ROWS => MULTIPLE_ACTIVE_ROWS,
DATA_WIDTH => DATA_WIDTH,
NROWS => NROWS,
NCOLS => NCOLS,
HADDR_WIDTH => HADDR_WIDTH,
SADDR_WIDTH => SADDR_WIDTH
)
port map(
clk => clk_i, -- master clock from external clock source (unbuffered)
lock => lock_i, -- valid synchronized clocks indicator
rst => rst, -- reset
rd => rd, -- host-side SDRAM read control from memory tester
wr => wr, -- host-side SDRAM write control from memory tester
uds => uds, -- host-side SDRAM upper data strobe
lds => lds, -- host-side SDRAM lower data strobe
rdPending => rdPending,
opBegun => opBegun, -- SDRAM memory read/write done indicator
earlyOpBegun => earlyOpBegun, -- SDRAM memory read/write done indicator
rdDone => rdDone, -- SDRAM memory read/write done indicator
done => done,
hAddr => hAddr, -- host-side address from memory tester
hDIn => hDIn, -- test data pattern from memory tester
hDOut => hDOut, -- SDRAM data output to memory tester
status => status, -- SDRAM controller state (for diagnostics)
cke => cke, -- SDRAM clock enable
ce_n => cs_n, -- SDRAM chip-select
ras_n => ras_n, -- SDRAM RAS
cas_n => cas_n, -- SDRAM CAS
we_n => we_n, -- SDRAM write-enable
ba => ba, -- SDRAM bank address
sAddr => sAddr, -- SDRAM address
sDIn => sData, -- input data from SDRAM
sDOut => sDOut, -- output data to SDRAM
sDOutEn => sDOutEn, -- enable drivers to send data to SDRAM
dqmh => dqmh, -- SDRAM DQMH
dqml => dqml -- SDRAM DQML
);
 
sData <= sDOut when sDOutEn = YES else (others => 'Z');
 
end arch;
/trunk/rtl/System09_Xess_XSA-3S1000/sdramcntl.vhd
1,1022 → 1,1146
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
 
package sdram is
 
-- SDRAM controller
component sdramCntl
generic(
FREQ : natural := 100_000; -- operating frequency in KHz
IN_PHASE : boolean := true; -- SDRAM and controller work on same or opposite clock edge
PIPE_EN : boolean := false; -- if true, enable pipelined read operations
MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
DATA_WIDTH : natural := 16; -- host & SDRAM data width
NROWS : natural := 8192; -- number of rows in SDRAM array
NCOLS : natural := 512; -- number of columns in SDRAM array
HADDR_WIDTH : natural := 24; -- host-side address width
SADDR_WIDTH : natural := 13 -- SDRAM-side address width
);
port(
-- host side
clk : in std_logic; -- master clock
lock : in std_logic; -- true if clock is stable
rst : in std_logic; -- reset
rd : in std_logic; -- initiate read operation
wr : in std_logic; -- initiate write operation
earlyOpBegun : out std_logic; -- read/write/self-refresh op has begun (async)
opBegun : out std_logic; -- read/write/self-refresh op has begun (clocked)
rdPending : out std_logic; -- true if read operation(s) are still in the pipeline
done : out std_logic; -- read or write operation is done
rdDone : out std_logic; -- read operation is done and data is available
hAddr : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host to SDRAM
hDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host to SDRAM
hDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM to host
status : out std_logic_vector(3 downto 0); -- diagnostic status of the FSM
-- SDRAM side
cke : out std_logic; -- clock-enable to SDRAM
ce_n : out std_logic; -- chip-select to SDRAM
ras_n : out std_logic; -- SDRAM row address strobe
cas_n : out std_logic; -- SDRAM column address strobe
we_n : out std_logic; -- SDRAM write enable
ba : out std_logic_vector(1 downto 0); -- SDRAM bank address
sAddr : out std_logic_vector(SADDR_WIDTH-1 downto 0); -- SDRAM row/column address
sDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM
sDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data to SDRAM
sDOutEn : out std_logic; -- true if data is output to SDRAM on sDOut
dqmh : out std_logic; -- enable upper-byte of SDRAM databus if true
dqml : out std_logic -- enable lower-byte of SDRAM databus if true
);
end component;
 
-- dual-port interface to the SDRAM controller
component dualport
generic(
PIPE_EN : boolean := false; -- enable pipelined read operations
PORT_TIME_SLOTS : std_logic_vector(15 downto 0) := "1111000011110000";
DATA_WIDTH : natural := 16; -- host & SDRAM data width
HADDR_WIDTH : natural := 23 -- host-side address width
);
port(
clk : in std_logic; -- master clock
 
-- host-side port 0
rst0 : in std_logic; -- reset
rd0 : in std_logic; -- initiate read operation
wr0 : in std_logic; -- initiate write operation
earlyOpBegun0 : out std_logic; -- read/write op has begun (async)
opBegun0 : out std_logic; -- read/write op has begun (clocked)
rdPending0 : out std_logic; -- true if read operation(s) are still in the pipeline
done0 : out std_logic; -- read or write operation is done
rdDone0 : out std_logic; -- read operation is done and data is available
hAddr0 : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host to SDRAM
hDIn0 : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host to SDRAM
hDOut0 : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM to host
status0 : out std_logic_vector(3 downto 0); -- diagnostic status of the SDRAM controller FSM
 
-- host-side port 1
rst1 : in std_logic;
rd1 : in std_logic;
wr1 : in std_logic;
earlyOpBegun1 : out std_logic;
opBegun1 : out std_logic;
rdPending1 : out std_logic;
done1 : out std_logic;
rdDone1 : out std_logic;
hAddr1 : in std_logic_vector(HADDR_WIDTH-1 downto 0);
hDIn1 : in std_logic_vector(DATA_WIDTH-1 downto 0);
hDOut1 : out std_logic_vector(DATA_WIDTH-1 downto 0);
status1 : out std_logic_vector(3 downto 0);
 
-- SDRAM controller port
rst : out std_logic;
rd : out std_logic;
wr : out std_logic;
earlyOpBegun : in std_logic;
opBegun : in std_logic;
rdPending : in std_logic;
done : in std_logic;
rdDone : in std_logic;
hAddr : out std_logic_vector(HADDR_WIDTH-1 downto 0);
hDIn : out std_logic_vector(DATA_WIDTH-1 downto 0);
hDOut : in std_logic_vector(DATA_WIDTH-1 downto 0);
status : in std_logic_vector(3 downto 0)
);
end component;
 
end package sdram;
 
 
 
 
--------------------------------------------------------------------
-- Company : XESS Corp.
-- Engineer : Dave Vanden Bout
-- Creation Date : 05/17/2005
-- Copyright : 2005, XESS Corp
-- Tool Versions : WebPACK 6.3.03i
--
-- Description:
-- SDRAM controller
--
-- Revision:
-- 1.4.0
--
-- Additional Comments:
-- 1.4.0:
-- Added generic parameter to enable/disable independent active rows in each bank.
-- 1.3.0:
-- Modified to allow independently active rows in each bank.
-- 1.2.0:
-- Modified to allow pipelining of read/write operations.
-- 1.1.0:
-- Initial release.
--
-- License:
-- This code can be freely distributed and modified as long as
-- this header is not removed.
--------------------------------------------------------------------
 
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;
use IEEE.numeric_std.all;
use WORK.common.all;
 
entity sdramCntl is
generic(
FREQ : natural := 100_000; -- operating frequency in KHz
IN_PHASE : boolean := true; -- SDRAM and controller work on same or opposite clock edge
PIPE_EN : boolean := false; -- if true, enable pipelined read operations
MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
DATA_WIDTH : natural := 16; -- host & SDRAM data width
NROWS : natural := 8192; -- number of rows in SDRAM array
NCOLS : natural := 512; -- number of columns in SDRAM array
HADDR_WIDTH : natural := 24; -- host-side address width
SADDR_WIDTH : natural := 13 -- SDRAM-side address width
);
port(
-- host side
clk : in std_logic; -- master clock
lock : in std_logic; -- true if clock is stable
rst : in std_logic; -- reset
rd : in std_logic; -- initiate read operation
wr : in std_logic; -- initiate write operation
earlyOpBegun : out std_logic; -- read/write/self-refresh op has begun (async)
opBegun : out std_logic; -- read/write/self-refresh op has begun (clocked)
rdPending : out std_logic; -- true if read operation(s) are still in the pipeline
done : out std_logic; -- read or write operation is done
rdDone : out std_logic; -- read operation is done and data is available
hAddr : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host to SDRAM
hDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host to SDRAM
hDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM to host
status : out std_logic_vector(3 downto 0); -- diagnostic status of the FSM
 
-- SDRAM side
cke : out std_logic; -- clock-enable to SDRAM
ce_n : out std_logic; -- chip-select to SDRAM
ras_n : out std_logic; -- SDRAM row address strobe
cas_n : out std_logic; -- SDRAM column address strobe
we_n : out std_logic; -- SDRAM write enable
ba : out std_logic_vector(1 downto 0); -- SDRAM bank address
sAddr : out std_logic_vector(SADDR_WIDTH-1 downto 0); -- SDRAM row/column address
sDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM
sDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data to SDRAM
sDOutEn : out std_logic; -- true if data is output to SDRAM on sDOut
dqmh : out std_logic; -- enable upper-byte of SDRAM databus if true
dqml : out std_logic -- enable lower-byte of SDRAM databus if true
);
end sdramCntl;
 
 
 
architecture arch of sdramCntl is
 
constant OUTPUT : std_logic := '1'; -- direction of dataflow w.r.t. this controller
constant INPUT : std_logic := '0';
constant NOP : std_logic := '0'; -- no operation
constant READ : std_logic := '1'; -- read operation
constant WRITE : std_logic := '1'; -- write operation
 
-- SDRAM timing parameters
constant Tinit : natural := 200; -- min initialization interval (us)
constant Tras : natural := 45; -- min interval between active to precharge commands (ns)
constant Trcd : natural := 20; -- min interval between active and R/W commands (ns)
constant Tref : natural := 64_000_000; -- maximum refresh interval (ns)
constant Trfc : natural := 66; -- duration of refresh operation (ns)
constant Trp : natural := 20; -- min precharge command duration (ns)
constant Twr : natural := 15; -- write recovery time (ns)
constant Txsr : natural := 75; -- exit self-refresh time (ns)
 
-- SDRAM timing parameters converted into clock cycles (based on FREQ)
constant NORM : natural := 1_000_000; -- normalize ns * KHz
constant INIT_CYCLES : natural := 1+((Tinit*FREQ)/1000); -- SDRAM power-on initialization interval
constant RAS_CYCLES : natural := 1+((Tras*FREQ)/NORM); -- active-to-precharge interval
constant RCD_CYCLES : natural := 1+((Trcd*FREQ)/NORM); -- active-to-R/W interval
constant REF_CYCLES : natural := 1+(((Tref/NROWS)*FREQ)/NORM); -- interval between row refreshes
constant RFC_CYCLES : natural := 1+((Trfc*FREQ)/NORM); -- refresh operation interval
constant RP_CYCLES : natural := 1+((Trp*FREQ)/NORM); -- precharge operation interval
constant WR_CYCLES : natural := 1+((Twr*FREQ)/NORM); -- write recovery time
constant XSR_CYCLES : natural := 1+((Txsr*FREQ)/NORM); -- exit self-refresh time
constant MODE_CYCLES : natural := 2; -- mode register setup time
constant CAS_CYCLES : natural := 3; -- CAS latency
constant RFSH_OPS : natural := 8; -- number of refresh operations needed to init SDRAM
 
-- timer registers that count down times for various SDRAM operations
signal timer_r, timer_x : natural range 0 to INIT_CYCLES; -- current SDRAM op time
signal rasTimer_r, rasTimer_x : natural range 0 to RAS_CYCLES; -- active-to-precharge time
signal wrTimer_r, wrTimer_x : natural range 0 to WR_CYCLES; -- write-to-precharge time
signal refTimer_r, refTimer_x : natural range 0 to REF_CYCLES; -- time between row refreshes
signal rfshCntr_r, rfshCntr_x : natural range 0 to NROWS; -- counts refreshes that are neede
signal nopCntr_r, nopCntr_x : natural range 0 to MAX_NOP; -- counts consecutive NOP operations
 
signal doSelfRfsh : std_logic; -- active when the NOP counter hits zero and self-refresh can start
 
-- states of the SDRAM controller state machine
type cntlState is (
INITWAIT, -- initialization - waiting for power-on initialization to complete
INITPCHG, -- initialization - initial precharge of SDRAM banks
INITSETMODE, -- initialization - set SDRAM mode
INITRFSH, -- initialization - do initial refreshes
RW, -- read/write/refresh the SDRAM
ACTIVATE, -- open a row of the SDRAM for reading/writing
REFRESHROW, -- refresh a row of the SDRAM
SELFREFRESH -- keep SDRAM in self-refresh mode with CKE low
);
signal state_r, state_x : cntlState; -- state register and next state
 
-- commands that are sent to the SDRAM to make it perform certain operations
-- commands use these SDRAM input pins (ce_n,ras_n,cas_n,we_n,dqmh,dqml)
subtype sdramCmd is unsigned(5 downto 0);
constant NOP_CMD : sdramCmd := "011100";
constant ACTIVE_CMD : sdramCmd := "001100";
constant READ_CMD : sdramCmd := "010100";
constant WRITE_CMD : sdramCmd := "010000";
constant PCHG_CMD : sdramCmd := "001011";
constant MODE_CMD : sdramCmd := "000011";
constant RFSH_CMD : sdramCmd := "000111";
 
-- SDRAM mode register
-- the SDRAM is placed in a non-burst mode (burst length = 1) with a 3-cycle CAS
subtype sdramMode is std_logic_vector(12 downto 0);
constant MODE : sdramMode := "000" & "0" & "00" & "011" & "0" & "000";
 
-- the host address is decomposed into these sets of SDRAM address components
constant ROW_LEN : natural := log2(NROWS); -- number of row address bits
constant COL_LEN : natural := log2(NCOLS); -- number of column address bits
signal bank : std_logic_vector(ba'range); -- bank address bits
signal row : std_logic_vector(ROW_LEN - 1 downto 0); -- row address within bank
signal col : std_logic_vector(sAddr'range); -- column address within row
 
-- registers that store the currently active row in each bank of the SDRAM
constant NUM_ACTIVE_ROWS : integer := int_select(MULTIPLE_ACTIVE_ROWS = false, 1, 2**ba'length);
type activeRowType is array(0 to NUM_ACTIVE_ROWS-1) of std_logic_vector(row'range);
signal activeRow_r, activeRow_x : activeRowType;
signal activeFlag_r, activeFlag_x : std_logic_vector(0 to NUM_ACTIVE_ROWS-1); -- indicates that some row in a bank is active
signal bankIndex : natural range 0 to NUM_ACTIVE_ROWS-1; -- bank address bits
signal activeBank_r, activeBank_x : std_logic_vector(ba'range); -- indicates the bank with the active row
signal doActivate : std_logic; -- indicates when a new row in a bank needs to be activated
 
-- there is a command bit embedded within the SDRAM column address
constant CMDBIT_POS : natural := 10; -- position of command bit
constant AUTO_PCHG_ON : std_logic := '1'; -- CMDBIT value to auto-precharge the bank
constant AUTO_PCHG_OFF : std_logic := '0'; -- CMDBIT value to disable auto-precharge
constant ONE_BANK : std_logic := '0'; -- CMDBIT value to select one bank
constant ALL_BANKS : std_logic := '1'; -- CMDBIT value to select all banks
 
-- status signals that indicate when certain operations are in progress
signal wrInProgress : std_logic; -- write operation in progress
signal rdInProgress : std_logic; -- read operation in progress
signal activateInProgress : std_logic; -- row activation is in progress
 
-- these registers track the progress of read and write operations
signal rdPipeline_r, rdPipeline_x : std_logic_vector(CAS_CYCLES+1 downto 0); -- pipeline of read ops in progress
signal wrPipeline_r, wrPipeline_x : std_logic_vector(0 downto 0); -- pipeline of write ops (only need 1 cycle)
 
-- registered outputs to host
signal opBegun_r, opBegun_x : std_logic; -- true when SDRAM read or write operation is started
signal hDOut_r, hDOut_x : std_logic_vector(hDOut'range); -- holds data read from SDRAM and sent to the host
signal hDOutOppPhase_r, hDOutOppPhase_x : std_logic_vector(hDOut'range); -- holds data read from SDRAM on opposite clock edge
 
-- registered outputs to SDRAM
signal cke_r, cke_x : std_logic; -- clock enable
signal cmd_r, cmd_x : sdramCmd; -- SDRAM command bits
signal ba_r, ba_x : std_logic_vector(ba'range); -- SDRAM bank address bits
signal sAddr_r, sAddr_x : std_logic_vector(sAddr'range); -- SDRAM row/column address
signal sData_r, sData_x : std_logic_vector(sDOut'range); -- SDRAM out databus
signal sDataDir_r, sDataDir_x : std_logic; -- SDRAM databus direction control bit
 
begin
 
-----------------------------------------------------------
-- attach some internal signals to the I/O ports
-----------------------------------------------------------
 
-- attach registered SDRAM control signals to SDRAM input pins
(ce_n, ras_n, cas_n, we_n, dqmh, dqml) <= cmd_r; -- SDRAM operation control bits
cke <= cke_r; -- SDRAM clock enable
ba <= ba_r; -- SDRAM bank address
sAddr <= sAddr_r; -- SDRAM address
sDOut <= sData_r; -- SDRAM output data bus
sDOutEn <= YES when sDataDir_r = OUTPUT else NO; -- output databus enable
 
-- attach some port signals
hDOut <= hDOut_r; -- data back to host
opBegun <= opBegun_r; -- true if requested operation has begun
 
 
-----------------------------------------------------------
-- compute the next state and outputs
-----------------------------------------------------------
 
combinatorial : process(rd, wr, hAddr, hDIn, hDOut_r, sDIn, state_r, opBegun_x,
activeFlag_r, activeRow_r, rdPipeline_r, wrPipeline_r,
hDOutOppPhase_r, nopCntr_r, lock, rfshCntr_r, timer_r, rasTimer_r,
wrTimer_r, refTimer_r, cmd_r, cke_r, activeBank_r, ba_r )
begin
 
-----------------------------------------------------------
-- setup default values for signals
-----------------------------------------------------------
 
opBegun_x <= NO; -- no operations have begun
earlyOpBegun <= opBegun_x;
cke_x <= YES; -- enable SDRAM clock
cmd_x <= NOP_CMD; -- set SDRAM command to no-operation
sDataDir_x <= INPUT; -- accept data from the SDRAM
sData_x <= hDIn(sData_x'range); -- output data from host to SDRAM
state_x <= state_r; -- reload these registers and flags
activeFlag_x <= activeFlag_r; -- with their existing values
activeRow_x <= activeRow_r;
activeBank_x <= activeBank_r;
rfshCntr_x <= rfshCntr_r;
 
-----------------------------------------------------------
-- setup default value for the SDRAM address
-----------------------------------------------------------
 
-- extract bank field from host address
ba_x <= hAddr(ba'length + ROW_LEN + COL_LEN - 1 downto ROW_LEN + COL_LEN);
if MULTIPLE_ACTIVE_ROWS = true then
bank <= (others => '0');
bankIndex <= CONV_INTEGER(ba_x);
else
bank <= ba_x;
bankIndex <= 0;
end if;
-- extract row, column fields from host address
row <= hAddr(ROW_LEN + COL_LEN - 1 downto COL_LEN);
-- extend column (if needed) until it is as large as the (SDRAM address bus - 1)
col <= (others => '0'); -- set it to all zeroes
col(COL_LEN-1 downto 0) <= hAddr(COL_LEN-1 downto 0);
-- by default, set SDRAM address to the column address with interspersed
-- command bit set to disable auto-precharge
sAddr_x <= col(col'high-1 downto CMDBIT_POS) & AUTO_PCHG_OFF
& col(CMDBIT_POS-1 downto 0);
 
-----------------------------------------------------------
-- manage the read and write operation pipelines
-----------------------------------------------------------
 
-- determine if read operations are in progress by the presence of
-- READ flags in the read pipeline
if rdPipeline_r(rdPipeline_r'high downto 1) /= 0 then
rdInProgress <= YES;
else
rdInProgress <= NO;
end if;
rdPending <= rdInProgress; -- tell the host if read operations are in progress
 
-- enter NOPs into the read and write pipeline shift registers by default
rdPipeline_x <= NOP & rdPipeline_r(rdPipeline_r'high downto 1);
wrPipeline_x(0) <= NOP;
 
-- transfer data from SDRAM to the host data register if a read flag has exited the pipeline
-- (the transfer occurs 1 cycle before we tell the host the read operation is done)
if rdPipeline_r(1) = READ then
hDOutOppPhase_x <= sDIn(hDOut'range); -- gets value on the SDRAM databus on the opposite phase
if IN_PHASE then
-- get the SDRAM data for the host directly from the SDRAM if the controller and SDRAM are in-phase
hDOut_x <= sDIn(hDOut'range);
else
-- otherwise get the SDRAM data that was gathered on the previous opposite clock edge
hDOut_x <= hDOutOppPhase_r(hDOut'range);
end if;
else
-- retain contents of host data registers if no data from the SDRAM has arrived yet
hDOutOppPhase_x <= hDOutOppPhase_r;
hDOut_x <= hDOut_r;
end if;
 
done <= rdPipeline_r(0) or wrPipeline_r(0); -- a read or write operation is done
rdDone <= rdPipeline_r(0); -- SDRAM data available when a READ flag exits the pipeline
 
-----------------------------------------------------------
-- manage row activation
-----------------------------------------------------------
 
-- request a row activation operation if the row of the current address
-- does not match the currently active row in the bank, or if no row
-- in the bank is currently active
if (bank /= activeBank_r) or (row /= activeRow_r(bankIndex)) or (activeFlag_r(bankIndex) = NO) then
doActivate <= YES;
else
doActivate <= NO;
end if;
 
-----------------------------------------------------------
-- manage self-refresh
-----------------------------------------------------------
 
-- enter self-refresh if neither a read or write is requested for MAX_NOP consecutive cycles.
if (rd = YES) or (wr = YES) then
-- any read or write resets NOP counter and exits self-refresh state
nopCntr_x <= 0;
doSelfRfsh <= NO;
elsif nopCntr_r /= MAX_NOP then
-- increment NOP counter whenever there is no read or write operation
nopCntr_x <= nopCntr_r + 1;
doSelfRfsh <= NO;
else
-- start self-refresh when counter hits maximum NOP count and leave counter unchanged
nopCntr_x <= nopCntr_r;
doSelfRfsh <= YES;
end if;
 
-----------------------------------------------------------
-- update the timers
-----------------------------------------------------------
 
-- row activation timer
if rasTimer_r /= 0 then
-- decrement a non-zero timer and set the flag
-- to indicate the row activation is still inprogress
rasTimer_x <= rasTimer_r - 1;
activateInProgress <= YES;
else
-- on timeout, keep the timer at zero and reset the flag
-- to indicate the row activation operation is done
rasTimer_x <= rasTimer_r;
activateInProgress <= NO;
end if;
 
-- write operation timer
if wrTimer_r /= 0 then
-- decrement a non-zero timer and set the flag
-- to indicate the write operation is still inprogress
wrTimer_x <= wrTimer_r - 1;
wrInPRogress <= YES;
else
-- on timeout, keep the timer at zero and reset the flag that
-- indicates a write operation is in progress
wrTimer_x <= wrTimer_r;
wrInPRogress <= NO;
end if;
 
-- refresh timer
if refTimer_r /= 0 then
refTimer_x <= refTimer_r - 1;
else
-- on timeout, reload the timer with the interval between row refreshes
-- and increment the counter for the number of row refreshes that are needed
refTimer_x <= REF_CYCLES;
rfshCntr_x <= rfshCntr_r + 1;
end if;
 
-- main timer for sequencing SDRAM operations
if timer_r /= 0 then
-- decrement the timer and do nothing else since the previous operation has not completed yet.
timer_x <= timer_r - 1;
status <= "0000";
else
-- the previous operation has completed once the timer hits zero
timer_x <= timer_r; -- by default, leave the timer at zero
 
-----------------------------------------------------------
-- compute the next state and outputs
-----------------------------------------------------------
case state_r is
 
-----------------------------------------------------------
-- let clock stabilize and then wait for the SDRAM to initialize
-----------------------------------------------------------
when INITWAIT =>
if lock = YES then
-- wait for SDRAM power-on initialization once the clock is stable
timer_x <= INIT_CYCLES; -- set timer for initialization duration
state_x <= INITPCHG;
else
-- disable SDRAM clock and return to this state if the clock is not stable
-- this insures the clock is stable before enabling the SDRAM
-- it also insures a clean startup if the SDRAM is currently in self-refresh mode
cke_x <= NO;
end if;
status <= "0001";
 
-----------------------------------------------------------
-- precharge all SDRAM banks after power-on initialization
-----------------------------------------------------------
when INITPCHG =>
cmd_x <= PCHG_CMD;
sAddr_x(CMDBIT_POS) <= ALL_BANKS; -- precharge all banks
timer_x <= RP_CYCLES; -- set timer for precharge operation duration
rfshCntr_x <= RFSH_OPS; -- set counter for refresh ops needed after precharge
state_x <= INITRFSH;
status <= "0010";
 
-----------------------------------------------------------
-- refresh the SDRAM a number of times after initial precharge
-----------------------------------------------------------
when INITRFSH =>
cmd_x <= RFSH_CMD;
timer_x <= RFC_CYCLES; -- set timer to refresh operation duration
rfshCntr_x <= rfshCntr_r - 1; -- decrement refresh operation counter
if rfshCntr_r = 1 then
state_x <= INITSETMODE; -- set the SDRAM mode once all refresh ops are done
end if;
status <= "0011";
 
-----------------------------------------------------------
-- set the mode register of the SDRAM
-----------------------------------------------------------
when INITSETMODE =>
cmd_x <= MODE_CMD;
sAddr_x <= MODE; -- output mode register bits on the SDRAM address bits
timer_x <= MODE_CYCLES; -- set timer for mode setting operation duration
state_x <= RW;
status <= "0100";
 
-----------------------------------------------------------
-- process read/write/refresh operations after initialization is done
-----------------------------------------------------------
when RW =>
-----------------------------------------------------------
-- highest priority operation: row refresh
-- do a refresh operation if the refresh counter is non-zero
-----------------------------------------------------------
if rfshCntr_r /= 0 then
-- wait for any row activations, writes or reads to finish before doing a precharge
if (activateInProgress = NO) and (wrInProgress = NO) and (rdInProgress = NO) then
cmd_x <= PCHG_CMD; -- initiate precharge of the SDRAM
sAddr_x(CMDBIT_POS) <= ALL_BANKS; -- precharge all banks
timer_x <= RP_CYCLES; -- set timer for this operation
activeFlag_x <= (others => NO); -- all rows are inactive after a precharge operation
state_x <= REFRESHROW; -- refresh the SDRAM after the precharge
end if;
status <= "0101";
-----------------------------------------------------------
-- do a host-initiated read operation
-----------------------------------------------------------
elsif rd = YES then
-- Wait one clock cycle if the bank address has just changed and each bank has its own active row.
-- This gives extra time for the row activation circuitry.
if (ba_x = ba_r) or (MULTIPLE_ACTIVE_ROWS=false) then
-- activate a new row if the current read is outside the active row or bank
if doActivate = YES then
-- activate new row only if all previous activations, writes, reads are done
if (activateInProgress = NO) and (wrInProgress = NO) and (rdInProgress = NO) then
cmd_x <= PCHG_CMD; -- initiate precharge of the SDRAM
sAddr_x(CMDBIT_POS) <= ONE_BANK; -- precharge this bank
timer_x <= RP_CYCLES; -- set timer for this operation
activeFlag_x(bankIndex) <= NO; -- rows in this bank are inactive after a precharge operation
state_x <= ACTIVATE; -- activate the new row after the precharge is done
end if;
-- read from the currently active row if no previous read operation
-- is in progress or if pipeline reads are enabled
-- we can always initiate a read even if a write is already in progress
elsif (rdInProgress = NO) or PIPE_EN then
cmd_x <= READ_CMD; -- initiate a read of the SDRAM
-- insert a flag into the pipeline shift register that will exit the end
-- of the shift register when the data from the SDRAM is available
rdPipeline_x <= READ & rdPipeline_r(rdPipeline_r'high downto 1);
opBegun_x <= YES; -- tell the host the requested operation has begun
end if;
end if;
status <= "0110";
-----------------------------------------------------------
-- do a host-initiated write operation
-----------------------------------------------------------
elsif wr = YES then
-- Wait one clock cycle if the bank address has just changed and each bank has its own active row.
-- This gives extra time for the row activation circuitry.
if (ba_x = ba_r) or (MULTIPLE_ACTIVE_ROWS=false) then
-- activate a new row if the current write is outside the active row or bank
if doActivate = YES then
-- activate new row only if all previous activations, writes, reads are done
if (activateInProgress = NO) and (wrInProgress = NO) and (rdInProgress = NO) then
cmd_x <= PCHG_CMD; -- initiate precharge of the SDRAM
sAddr_x(CMDBIT_POS) <= ONE_BANK; -- precharge this bank
timer_x <= RP_CYCLES; -- set timer for this operation
activeFlag_x(bankIndex) <= NO; -- rows in this bank are inactive after a precharge operation
state_x <= ACTIVATE; -- activate the new row after the precharge is done
end if;
-- write to the currently active row if no previous read operations are in progress
elsif rdInProgress = NO then
cmd_x <= WRITE_CMD; -- initiate the write operation
sDataDir_x <= OUTPUT; -- turn on drivers to send data to SDRAM
-- set timer so precharge doesn't occur too soon after write operation
wrTimer_x <= WR_CYCLES;
-- insert a flag into the 1-bit pipeline shift register that will exit on the
-- next cycle. The write into SDRAM is not actually done by that time, but
-- this doesn't matter to the host
wrPipeline_x(0) <= WRITE;
opBegun_x <= YES; -- tell the host the requested operation has begun
end if;
end if;
status <= "0111";
-----------------------------------------------------------
-- do a host-initiated self-refresh operation
-----------------------------------------------------------
elsif doSelfRfsh = YES then
-- wait until all previous activations, writes, reads are done
if (activateInProgress = NO) and (wrInProgress = NO) and (rdInProgress = NO) then
cmd_x <= PCHG_CMD; -- initiate precharge of the SDRAM
sAddr_x(CMDBIT_POS) <= ALL_BANKS; -- precharge all banks
timer_x <= RP_CYCLES; -- set timer for this operation
activeFlag_x <= (others => NO); -- all rows are inactive after a precharge operation
state_x <= SELFREFRESH; -- self-refresh the SDRAM after the precharge
end if;
status <= "1000";
-----------------------------------------------------------
-- no operation
-----------------------------------------------------------
else
state_x <= RW; -- continue to look for SDRAM operations to execute
status <= "1001";
end if;
 
-----------------------------------------------------------
-- activate a row of the SDRAM
-----------------------------------------------------------
when ACTIVATE =>
cmd_x <= ACTIVE_CMD;
sAddr_x <= (others => '0'); -- output the address for the row to be activated
sAddr_x(row'range) <= row;
activeBank_x <= bank;
activeRow_x(bankIndex) <= row; -- store the new active SDRAM row address
activeFlag_x(bankIndex) <= YES; -- the SDRAM is now active
rasTimer_x <= RAS_CYCLES; -- minimum time before another precharge can occur
timer_x <= RCD_CYCLES; -- minimum time before a read/write operation can occur
state_x <= RW; -- return to do read/write operation that initiated this activation
status <= "1010";
 
-----------------------------------------------------------
-- refresh a row of the SDRAM
-----------------------------------------------------------
when REFRESHROW =>
cmd_x <= RFSH_CMD;
timer_x <= RFC_CYCLES; -- refresh operation interval
rfshCntr_x <= rfshCntr_r - 1; -- decrement the number of needed row refreshes
state_x <= RW; -- process more SDRAM operations after refresh is done
status <= "1011";
 
-----------------------------------------------------------
-- place the SDRAM into self-refresh and keep it there until further notice
-----------------------------------------------------------
when SELFREFRESH =>
if (doSelfRfsh = YES) or (lock = NO) then
-- keep the SDRAM in self-refresh mode as long as requested and until there is a stable clock
cmd_x <= RFSH_CMD; -- output the refresh command; this is only needed on the first clock cycle
cke_x <= NO; -- disable the SDRAM clock
else
-- else exit self-refresh mode and start processing read and write operations
cke_x <= YES; -- restart the SDRAM clock
rfshCntr_x <= 0; -- no refreshes are needed immediately after leaving self-refresh
activeFlag_x <= (others => NO); -- self-refresh deactivates all rows
timer_x <= XSR_CYCLES; -- wait this long until read and write operations can resume
state_x <= RW;
end if;
status <= "1100";
 
-----------------------------------------------------------
-- unknown state
-----------------------------------------------------------
when others =>
state_x <= INITWAIT; -- reset state if in erroneous state
status <= "1101";
 
end case;
end if;
end process combinatorial;
 
 
-----------------------------------------------------------
-- update registers on the appropriate clock edge
-----------------------------------------------------------
 
update : process(rst, clk)
begin
 
if rst = YES then
-- asynchronous reset
state_r <= INITWAIT;
activeFlag_r <= (others => NO);
rfshCntr_r <= 0;
timer_r <= 0;
refTimer_r <= REF_CYCLES;
rasTimer_r <= 0;
wrTimer_r <= 0;
nopCntr_r <= 0;
opBegun_r <= NO;
rdPipeline_r <= (others => '0');
wrPipeline_r <= (others => '0');
cke_r <= NO;
cmd_r <= NOP_CMD;
ba_r <= (others => '0');
sAddr_r <= (others => '0');
sData_r <= (others => '0');
sDataDir_r <= INPUT;
hDOut_r <= (others => '0');
elsif rising_edge(clk) then
state_r <= state_x;
activeBank_r <= activeBank_x;
activeRow_r <= activeRow_x;
activeFlag_r <= activeFlag_x;
rfshCntr_r <= rfshCntr_x;
timer_r <= timer_x;
refTimer_r <= refTimer_x;
rasTimer_r <= rasTimer_x;
wrTimer_r <= wrTimer_x;
nopCntr_r <= nopCntr_x;
opBegun_r <= opBegun_x;
rdPipeline_r <= rdPipeline_x;
wrPipeline_r <= wrPipeline_x;
cke_r <= cke_x;
cmd_r <= cmd_x;
ba_r <= ba_x;
sAddr_r <= sAddr_x;
sData_r <= sData_x;
sDataDir_r <= sDataDir_x;
hDOut_r <= hDOut_x;
end if;
 
-- the register that gets data from the SDRAM and holds it for the host
-- is clocked on the opposite edge. We don't use this register if IN_PHASE=TRUE.
if rst = YES then
hDOutOppPhase_r <= (others => '0');
elsif falling_edge(clk) then
hDOutOppPhase_r <= hDOutOppPhase_x;
end if;
 
end process update;
 
end arch;
 
 
 
 
--------------------------------------------------------------------
-- Company : XESS Corp.
-- Engineer : Dave Vanden Bout
-- Creation Date : 06/01/2005
-- Copyright : 2005, XESS Corp
-- Tool Versions : WebPACK 6.3.03i
--
-- Description:
-- Dual-port front-end for SDRAM controller. Supports two
-- independent I/O ports to the SDRAM.
--
-- Revision:
-- 1.0.0
--
-- Additional Comments:
--
-- License:
-- This code can be freely distributed and modified as long as
-- this header is not removed.
--------------------------------------------------------------------
 
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;
use IEEE.numeric_std.all;
use WORK.common.all;
 
entity dualport is
generic(
PIPE_EN : boolean := false; -- enable pipelined read operations
PORT_TIME_SLOTS : std_logic_vector(15 downto 0) := "1111000011110000";
DATA_WIDTH : natural := 16; -- host & SDRAM data width
HADDR_WIDTH : natural := 23 -- host-side address width
);
port(
clk : in std_logic; -- master clock
 
-- host-side port 0
rst0 : in std_logic; -- reset
rd0 : in std_logic; -- initiate read operation
wr0 : in std_logic; -- initiate write operation
earlyOpBegun0 : out std_logic; -- read/write op has begun (async)
opBegun0 : out std_logic; -- read/write op has begun (clocked)
rdPending0 : out std_logic; -- true if read operation(s) are still in the pipeline
done0 : out std_logic; -- read or write operation is done
rdDone0 : out std_logic; -- read operation is done and data is available
hAddr0 : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host to SDRAM
hDIn0 : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host to SDRAM
hDOut0 : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM to host
status0 : out std_logic_vector(3 downto 0); -- diagnostic status of the SDRAM controller FSM
 
-- host-side port 1
rst1 : in std_logic;
rd1 : in std_logic;
wr1 : in std_logic;
earlyOpBegun1 : out std_logic;
opBegun1 : out std_logic;
rdPending1 : out std_logic;
done1 : out std_logic;
rdDone1 : out std_logic;
hAddr1 : in std_logic_vector(HADDR_WIDTH-1 downto 0);
hDIn1 : in std_logic_vector(DATA_WIDTH-1 downto 0);
hDOut1 : out std_logic_vector(DATA_WIDTH-1 downto 0);
status1 : out std_logic_vector(3 downto 0);
 
-- SDRAM controller port
rst : out std_logic;
rd : out std_logic;
wr : out std_logic;
earlyOpBegun : in std_logic;
opBegun : in std_logic;
rdPending : in std_logic;
done : in std_logic;
rdDone : in std_logic;
hAddr : out std_logic_vector(HADDR_WIDTH-1 downto 0);
hDIn : out std_logic_vector(DATA_WIDTH-1 downto 0);
hDOut : in std_logic_vector(DATA_WIDTH-1 downto 0);
status : in std_logic_vector(3 downto 0)
);
end dualport;
 
 
 
architecture arch of dualport is
-- The door signal controls whether the read/write signal from the active port
-- is allowed through to the read/write inputs of the SDRAM controller.
type doorState is (OPENED, CLOSED);
signal door_r, door_x : doorState;
 
-- The port signal indicates which port is connected to the SDRAM controller.
type portState is (PORT0, PORT1);
signal port_r, port_x : portState;
 
signal switch : std_logic; -- indicates that the active port should be switched
signal inProgress : std_logic; -- the active port has a read/write op in-progress
signal rd_i : std_logic; -- read signal to the SDRAM controller (internal copy)
signal wr_i : std_logic; -- write signal to the SDRAM controller (internal copy)
signal earlyOpBegun0_i, earlyOpBegun1_i : std_logic; -- (internal copies)
signal slot_r, slot_x : std_logic_vector(PORT_TIME_SLOTS'range); -- time-slot allocation shift-register
begin
 
----------------------------------------------------------------------------
-- multiplex the SDRAM controller port signals to/from the dual host-side ports
----------------------------------------------------------------------------
 
-- send the SDRAM controller the address and data from the currently active port
hAddr <= hAddr0 when port_r = PORT0 else hAddr1;
hDIn <= hDIn0 when port_r = PORT0 else hDIn1;
 
-- both ports get the data from the SDRAM but only the active port will use it
hDOut0 <= hDOut;
hDOut1 <= hDOut;
 
-- send the SDRAM controller status to the active port and give the inactive port an inactive status code
status0 <= status when port_r = PORT0 else "1111";
status1 <= status when port_r = PORT1 else "1111";
 
-- either port can reset the SDRAM controller
rst <= rst0 or rst1;
 
-- apply the read signal from the active port to the SDRAM controller only if the door is open.
rd_i <= rd0 when (port_r = PORT0) and (door_r = OPENED) else
rd1 when (port_r = PORT1) and (door_r = OPENED) else
NO;
rd <= rd_i;
 
-- apply the write signal from the active port to the SDRAM controller only if the door is open.
wr_i <= wr0 when (port_r = PORT0) and (door_r = OPENED) else
wr1 when (port_r = PORT1) and (door_r = OPENED) else
NO;
wr <= wr_i;
 
-- send the status signals for various SDRAM controller operations back to the active port
earlyOpBegun0_i <= earlyOpBegun when port_r = PORT0 else NO;
earlyOpBegun0 <= earlyOpBegun0_i;
earlyOpBegun1_i <= earlyOpBegun when port_r = PORT1 else NO;
earlyOpBegun1 <= earlyOpBegun1_i;
rdPending0 <= rdPending when port_r = PORT0 else NO;
rdPending1 <= rdPending when port_r = PORT1 else NO;
done0 <= done when port_r = PORT0 else NO;
done1 <= done when port_r = PORT1 else NO;
rdDone0 <= rdDone when port_r = PORT0 else NO;
rdDone1 <= rdDone when port_r = PORT1 else NO;
 
----------------------------------------------------------------------------
-- Indicate when the active port needs to be switched. A switch occurs if
-- a read or write operation is requested on the port that is not currently active and:
-- 1) no R/W operation is being performed on the active port or
-- 2) a R/W operation is in progress on the active port, but the time-slot allocation
-- register is giving precedence to the inactive port. (The R/W operation on the
-- active port will be completed before the switch is made.)
-- This rule keeps the active port from hogging all the bandwidth.
----------------------------------------------------------------------------
switch <= (rd0 or wr0) when (port_r = PORT1) and (((rd1 = NO) and (wr1 = NO)) or (slot_r(0) = '0')) else
(rd1 or wr1) when (port_r = PORT0) and (((rd0 = NO) and (wr0 = NO)) or (slot_r(0) = '1')) else
NO;
 
----------------------------------------------------------------------------
-- Indicate when an operation on the active port is in-progress and
-- can't be interrupted by a switch to the other port. (Only read operations
-- are looked at since write operations always complete in one cycle once they
-- are initiated.)
----------------------------------------------------------------------------
inProgress <= rdPending or (rd_i and earlyOpBegun);
 
----------------------------------------------------------------------------
-- Update the time-slot allocation shift-register. The port with priority is indicated by the
-- least-significant bit of the register. The register is rotated right if:
-- 1) the current R/W operation has started, and
-- 2) both ports are requesting R/W operations (indicating contention), and
-- 3) the currently active port matches the port that currently has priority.
-- Under these conditions, the current time slot port allocation has been used so
-- the shift register is rotated right to bring the next port time-slot allocation
-- bit into play.
----------------------------------------------------------------------------
slot_x <= slot_r(0) & slot_r(slot_r'high downto 1) when (earlyOpBegun = YES) and
( ((rd0 = YES) or (wr0 = YES)) and ((rd1 = YES) or (wr1 = YES)) ) and
( ((port_r = PORT0) and (slot_r(0) = '0')) or ((port_r = PORT1) and (slot_r(0) = '1')) )
else slot_r;
 
----------------------------------------------------------------------------
-- Determine which port will be active on the next cycle. The active port is switched if:
-- 1) the currently active port has finished its current R/W operation, and
-- 2) there are no pending operations in progress, and
-- 3) the port switch indicator is active.
----------------------------------------------------------------------------
port_process : process(port_r, inProgress, switch, done)
begin
port_x <= port_r; -- by default, the active port is not changed
case port_r is
when PORT0 =>
if (inProgress = NO) and (switch = YES) and (PIPE_EN or (done = YES)) then
port_x <= PORT1;
end if;
when PORT1 =>
if (inProgress = NO) and (switch = YES) and (PIPE_EN or (done = YES)) then
port_x <= PORT0;
end if;
when others =>
port_x <= port_r;
end case;
end process port_process;
 
-----------------------------------------------------------
-- Determine if the door is open for the active port to initiate new R/W operations to
-- the SDRAM controller. If the door is open and R/W operations are in progress but
-- a switch to the other port is indicated, then the door is closed to prevent any
-- further R/W operations from the active port. The door is re-opened once all
-- in-progress operations are completed, at which time the switch to the other port
-- is also completed so it can issue its own R/W commands.
-----------------------------------------------------------
door_process : process(door_r, inProgress, switch)
begin
door_x <= door_r; -- by default, the door remains as it is
case door_r is
when OPENED =>
if (inProgress = YES) and (switch = YES) then
door_x <= CLOSED;
end if;
when CLOSED =>
if inProgress = NO then
door_x <= OPENED;
end if;
when others =>
door_x <= door_r;
end case;
end process door_process;
 
-----------------------------------------------------------
-- update registers on the appropriate clock edge
-----------------------------------------------------------
update : process(rst0, rst1, clk)
begin
if (rst0 = YES) or (rst1 = YES) then
-- asynchronous reset
door_r <= CLOSED;
port_r <= PORT0;
slot_r <= PORT_TIME_SLOTS;
opBegun0 <= NO;
opBegun1 <= NO;
elsif rising_edge(clk) then
door_r <= door_x;
port_r <= port_x;
slot_r <= slot_x;
-- opBegun signals are cycle-delayed versions of earlyOpBegun signals.
-- We can't use the actual opBegun signal from the SDRAM controller
-- because it would be turned off if the active port was switched on the
-- cycle immediately after earlyOpBegun went active.
opBegun0 <= earlyOpBegun0_i;
opBegun1 <= earlyOpBegun1_i;
end if;
end process update;
 
end arch;
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
 
package sdram is
 
-- SDRAM controller
component sdramCntl
generic(
FREQ : natural := 100_000; -- operating frequency in KHz
IN_PHASE : boolean := true; -- SDRAM and controller work on same or opposite clock edge
PIPE_EN : boolean := false; -- if true, enable pipelined read operations
MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
DATA_WIDTH : natural := 16; -- host & SDRAM data width
NROWS : natural := 8192; -- number of rows in SDRAM array
NCOLS : natural := 512; -- number of columns in SDRAM array
HADDR_WIDTH : natural := 24; -- host-side address width
SADDR_WIDTH : natural := 13 -- SDRAM-side address width
);
port(
-- host side
clk : in std_logic; -- master clock
lock : in std_logic; -- true if clock is stable
rst : in std_logic; -- reset
rd : in std_logic; -- initiate read operation
wr : in std_logic; -- initiate write operation
uds : in std_logic; -- upper byte data strobe
lds : in std_logic; -- lower byte data strobe
earlyOpBegun : out std_logic; -- read/write/self-refresh op has begun (async)
opBegun : out std_logic; -- read/write/self-refresh op has begun (clocked)
rdPending : out std_logic; -- true if read operation(s) are still in the pipeline
done : out std_logic; -- read or write operation is done
rdDone : out std_logic; -- read operation is done and data is available
hAddr : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host to SDRAM
hDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host to SDRAM
hDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM to host
status : out std_logic_vector(3 downto 0); -- diagnostic status of the FSM
-- SDRAM side
cke : out std_logic; -- clock-enable to SDRAM
ce_n : out std_logic; -- chip-select to SDRAM
ras_n : out std_logic; -- SDRAM row address strobe
cas_n : out std_logic; -- SDRAM column address strobe
we_n : out std_logic; -- SDRAM write enable
ba : out std_logic_vector(1 downto 0); -- SDRAM bank address
sAddr : out std_logic_vector(SADDR_WIDTH-1 downto 0); -- SDRAM row/column address
sDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data to SDRAM
sDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM
sDOutEn : out std_logic; -- true if data is output to SDRAM on sDOut
dqmh : out std_logic; -- enable upper-byte of SDRAM databus if true
dqml : out std_logic -- enable lower-byte of SDRAM databus if true
);
end component;
 
-- dual-port interface to the SDRAM controller
component dualport
generic(
PIPE_EN : boolean := false; -- enable pipelined read operations
PORT_TIME_SLOTS : std_logic_vector(15 downto 0) := "1111000011110000";
DATA_WIDTH : natural := 16; -- host & SDRAM data width
HADDR_WIDTH : natural := 23 -- host-side address width
);
port(
clk : in std_logic; -- master clock
 
-- host-side port 0
rst0 : in std_logic; -- reset
rd0 : in std_logic; -- initiate read operation
wr0 : in std_logic; -- initiate write operation
uds0 : in std_logic; -- upper data strobe
lds0 : in std_logic; -- lower data strobe
earlyOpBegun0 : out std_logic; -- read/write op has begun (async)
opBegun0 : out std_logic; -- read/write op has begun (clocked)
rdPending0 : out std_logic; -- true if read operation(s) are still in the pipeline
done0 : out std_logic; -- read or write operation is done
rdDone0 : out std_logic; -- read operation is done and data is available
hAddr0 : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host to SDRAM
hDIn0 : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host to SDRAM
hDOut0 : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM to host
status0 : out std_logic_vector(3 downto 0); -- diagnostic status of the SDRAM controller FSM
 
-- host-side port 1
rst1 : in std_logic;
rd1 : in std_logic;
wr1 : in std_logic;
uds1 : in std_logic;
lds1 : in std_logic;
earlyOpBegun1 : out std_logic;
opBegun1 : out std_logic;
rdPending1 : out std_logic;
done1 : out std_logic;
rdDone1 : out std_logic;
hAddr1 : in std_logic_vector(HADDR_WIDTH-1 downto 0);
hDIn1 : in std_logic_vector(DATA_WIDTH-1 downto 0);
hDOut1 : out std_logic_vector(DATA_WIDTH-1 downto 0);
status1 : out std_logic_vector(3 downto 0);
 
-- SDRAM controller port
rst : out std_logic;
rd : out std_logic;
wr : out std_logic;
earlyOpBegun : in std_logic;
opBegun : in std_logic;
rdPending : in std_logic;
done : in std_logic;
rdDone : in std_logic;
hAddr : out std_logic_vector(HADDR_WIDTH-1 downto 0);
hDIn : out std_logic_vector(DATA_WIDTH-1 downto 0);
hDOut : in std_logic_vector(DATA_WIDTH-1 downto 0);
status : in std_logic_vector(3 downto 0)
);
end component;
 
end package sdram;
 
 
 
 
--------------------------------------------------------------------
-- Company : XESS Corp.
-- Engineer : Dave Vanden Bout
-- Creation Date : 05/17/2005
-- Copyright : 2005, XESS Corp
-- Tool Versions : WebPACK 6.3.03i
--
-- Description:
-- SDRAM controller
--
-- Revision:
-- 1.5.0
--
-- Additional Comments:
-- 1.5.0:
-- John Kent 2008-03-28
-- added upper and lower data strobes.
-- 1.4.0:
-- Added generic parameter to enable/disable independent active rows in each bank.
-- 1.3.0:
-- Modified to allow independently active rows in each bank.
-- 1.2.0:
-- Modified to allow pipelining of read/write operations.
-- 1.1.0:
-- Initial release.
--
-- License:
-- This code can be freely distributed and modified as long as
-- this header is not removed.
--------------------------------------------------------------------
 
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;
use IEEE.numeric_std.all;
use WORK.common.all;
 
entity sdramCntl is
generic(
FREQ : natural := 100_000; -- operating frequency in KHz
IN_PHASE : boolean := true; -- SDRAM and controller work on same or opposite clock edge
PIPE_EN : boolean := false; -- if true, enable pipelined read operations
MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
DATA_WIDTH : natural := 16; -- host & SDRAM data width
NROWS : natural := 8192; -- number of rows in SDRAM array
NCOLS : natural := 512; -- number of columns in SDRAM array
HADDR_WIDTH : natural := 24; -- host-side address width
SADDR_WIDTH : natural := 13 -- SDRAM-side address width
);
port(
-- host side
clk : in std_logic; -- master clock
lock : in std_logic; -- true if clock is stable
rst : in std_logic; -- reset
rd : in std_logic; -- initiate read operation
wr : in std_logic; -- initiate write operation
uds : in std_logic; -- upper data strobe
lds : in std_logic; -- lower data strobe
earlyOpBegun : out std_logic; -- read/write/self-refresh op has begun (async)
opBegun : out std_logic; -- read/write/self-refresh op has begun (clocked)
rdPending : out std_logic; -- true if read operation(s) are still in the pipeline
done : out std_logic; -- read or write operation is done
rdDone : out std_logic; -- read operation is done and data is available
hAddr : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host to SDRAM
hDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host to SDRAM
hDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM to host
status : out std_logic_vector(3 downto 0); -- diagnostic status of the FSM
 
-- SDRAM side
cke : out std_logic; -- clock-enable to SDRAM
ce_n : out std_logic; -- chip-select to SDRAM
ras_n : out std_logic; -- SDRAM row address strobe
cas_n : out std_logic; -- SDRAM column address strobe
we_n : out std_logic; -- SDRAM write enable
ba : out std_logic_vector(1 downto 0); -- SDRAM bank address
sAddr : out std_logic_vector(SADDR_WIDTH-1 downto 0); -- SDRAM row/column address
sDIn : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM
sDOut : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data to SDRAM
sDOutEn : out std_logic; -- true if data is output to SDRAM on sDOut
dqmh : out std_logic; -- enable upper-byte of SDRAM databus if true
dqml : out std_logic -- enable lower-byte of SDRAM databus if true
);
end sdramCntl;
 
 
 
architecture arch of sdramCntl is
 
constant OUTPUT : std_logic := '1'; -- direction of dataflow w.r.t. this controller
constant INPUT : std_logic := '0';
constant NOP : std_logic := '0'; -- no operation
constant READ : std_logic := '1'; -- read operation
constant WRITE : std_logic := '1'; -- write operation
 
-- SDRAM timing parameters
constant Tinit : natural := 200; -- min initialization interval (us)
constant Tras : natural := 45; -- min interval between active to precharge commands (ns)
constant Trcd : natural := 20; -- min interval between active and R/W commands (ns)
constant Tref : natural := 64_000_000; -- maximum refresh interval (ns)
constant Trfc : natural := 66; -- duration of refresh operation (ns)
constant Trp : natural := 20; -- min precharge command duration (ns)
constant Twr : natural := 15; -- write recovery time (ns)
constant Txsr : natural := 75; -- exit self-refresh time (ns)
 
-- SDRAM timing parameters converted into clock cycles (based on FREQ)
constant NORM : natural := 1_000_000; -- normalize ns * KHz
constant INIT_CYCLES : natural := 1+((Tinit*FREQ)/1000); -- SDRAM power-on initialization interval
constant RAS_CYCLES : natural := 1+((Tras*FREQ)/NORM); -- active-to-precharge interval
constant RCD_CYCLES : natural := 1+((Trcd*FREQ)/NORM); -- active-to-R/W interval
constant REF_CYCLES : natural := 1+(((Tref/NROWS)*FREQ)/NORM); -- interval between row refreshes
constant RFC_CYCLES : natural := 1+((Trfc*FREQ)/NORM); -- refresh operation interval
constant RP_CYCLES : natural := 1+((Trp*FREQ)/NORM); -- precharge operation interval
constant WR_CYCLES : natural := 1+((Twr*FREQ)/NORM); -- write recovery time
constant XSR_CYCLES : natural := 1+((Txsr*FREQ)/NORM); -- exit self-refresh time
constant MODE_CYCLES : natural := 2; -- mode register setup time
constant CAS_CYCLES : natural := 3; -- CAS latency
constant RFSH_OPS : natural := 8; -- number of refresh operations needed to init SDRAM
 
-- timer registers that count down times for various SDRAM operations
signal timer_r, timer_x : natural range 0 to INIT_CYCLES; -- current SDRAM op time
signal rasTimer_r, rasTimer_x : natural range 0 to RAS_CYCLES; -- active-to-precharge time
signal wrTimer_r, wrTimer_x : natural range 0 to WR_CYCLES; -- write-to-precharge time
signal refTimer_r, refTimer_x : natural range 0 to REF_CYCLES; -- time between row refreshes
signal rfshCntr_r, rfshCntr_x : natural range 0 to NROWS; -- counts refreshes that are neede
signal nopCntr_r, nopCntr_x : natural range 0 to MAX_NOP; -- counts consecutive NOP operations
 
signal doSelfRfsh : std_logic; -- active when the NOP counter hits zero and self-refresh can start
 
-- states of the SDRAM controller state machine
type cntlState is (
INITWAIT, -- initialization - waiting for power-on initialization to complete
INITPCHG, -- initialization - initial precharge of SDRAM banks
INITSETMODE, -- initialization - set SDRAM mode
INITRFSH, -- initialization - do initial refreshes
RW, -- read/write/refresh the SDRAM
ACTIVATE, -- open a row of the SDRAM for reading/writing
REFRESHROW, -- refresh a row of the SDRAM
SELFREFRESH -- keep SDRAM in self-refresh mode with CKE low
);
signal state_r, state_x : cntlState; -- state register and next state
 
-- commands that are sent to the SDRAM to make it perform certain operations
-- commands use these SDRAM input pins (ce_n,ras_n,cas_n,we_n,dqmh,dqml)
-- subtype sdramCmd is unsigned(5 downto 0);
-- constant NOP_CMD : sdramCmd := "011100";
-- constant ACTIVE_CMD : sdramCmd := "001100";
-- constant READ_CMD : sdramCmd := "010100";
-- constant WRITE_CMD : sdramCmd := "010000";
-- constant PCHG_CMD : sdramCmd := "001011";
-- constant MODE_CMD : sdramCmd := "000011";
-- constant RFSH_CMD : sdramCmd := "000111";
 
-- commands that are sent to the SDRAM to make it perform certain operations
-- commands use these SDRAM input pins (ce_n,ras_n,cas_n,we_n)
subtype sdramCmd is unsigned(3 downto 0);
constant NOP_CMD : sdramCmd := "0111";
constant ACTIVE_CMD : sdramCmd := "0011";
constant READ_CMD : sdramCmd := "0101";
constant WRITE_CMD : sdramCmd := "0100";
constant PCHG_CMD : sdramCmd := "0010";
constant MODE_CMD : sdramCmd := "0000";
constant RFSH_CMD : sdramCmd := "0001";
 
-- SDRAM mode register
-- the SDRAM is placed in a non-burst mode (burst length = 1) with a 3-cycle CAS
subtype sdramMode is std_logic_vector(12 downto 0);
constant MODE : sdramMode := "000" & "0" & "00" & "011" & "0" & "000";
 
-- the host address is decomposed into these sets of SDRAM address components
constant ROW_LEN : natural := log2(NROWS); -- number of row address bits
constant COL_LEN : natural := log2(NCOLS); -- number of column address bits
signal bank : std_logic_vector(ba'range); -- bank address bits
signal row : std_logic_vector(ROW_LEN - 1 downto 0); -- row address within bank
signal col : std_logic_vector(sAddr'range); -- column address within row
 
-- registers that store the currently active row in each bank of the SDRAM
constant NUM_ACTIVE_ROWS : integer := int_select(MULTIPLE_ACTIVE_ROWS = false, 1, 2**ba'length);
type activeRowType is array(0 to NUM_ACTIVE_ROWS-1) of std_logic_vector(row'range);
signal activeRow_r, activeRow_x : activeRowType;
signal activeFlag_r, activeFlag_x : std_logic_vector(0 to NUM_ACTIVE_ROWS-1); -- indicates that some row in a bank is active
signal bankIndex : natural range 0 to NUM_ACTIVE_ROWS-1; -- bank address bits
signal activeBank_r, activeBank_x : std_logic_vector(ba'range); -- indicates the bank with the active row
signal doActivate : std_logic; -- indicates when a new row in a bank needs to be activated
 
-- there is a command bit embedded within the SDRAM column address
constant CMDBIT_POS : natural := 10; -- position of command bit
constant AUTO_PCHG_ON : std_logic := '1'; -- CMDBIT value to auto-precharge the bank
constant AUTO_PCHG_OFF : std_logic := '0'; -- CMDBIT value to disable auto-precharge
constant ONE_BANK : std_logic := '0'; -- CMDBIT value to select one bank
constant ALL_BANKS : std_logic := '1'; -- CMDBIT value to select all banks
 
-- status signals that indicate when certain operations are in progress
signal wrInProgress : std_logic; -- write operation in progress
signal rdInProgress : std_logic; -- read operation in progress
signal activateInProgress : std_logic; -- row activation is in progress
 
-- these registers track the progress of read and write operations
signal rdPipeline_r, rdPipeline_x : std_logic_vector(CAS_CYCLES+1 downto 0); -- pipeline of read ops in progress
signal wrPipeline_r, wrPipeline_x : std_logic_vector(0 downto 0); -- pipeline of write ops (only need 1 cycle)
 
-- registered outputs to host
signal opBegun_r, opBegun_x : std_logic; -- true when SDRAM read or write operation is started
signal hDOut_r, hDOut_x : std_logic_vector(hDOut'range); -- holds data read from SDRAM and sent to the host
signal hDOutOppPhase_r, hDOutOppPhase_x : std_logic_vector(hDOut'range); -- holds data read from SDRAM on opposite clock edge
 
-- registered outputs to SDRAM
signal cke_r, cke_x : std_logic; -- clock enable
signal cmd_r, cmd_x : sdramCmd; -- SDRAM command bits
signal ba_r, ba_x : std_logic_vector(ba'range); -- SDRAM bank address bits
signal sAddr_r, sAddr_x : std_logic_vector(sAddr'range); -- SDRAM row/column address
signal sData_r, sData_x : std_logic_vector(sDOut'range); -- SDRAM out databus
signal dqmh_r, dqmh_x : std_logic; -- SDRAM upper data mask
signal dqml_r, dqml_x : std_logic; -- SDRAM lower data mask
signal sDataDir_r, sDataDir_x : std_logic; -- SDRAM databus direction control bit
 
begin
 
assign_single_port : process( cmd_r, dqmh_r, dqml_r, cke_r,
ba_r, sAddr_r,
sData_r, sDataDir_r,
hDOut_r, opBegun_r )
begin
-----------------------------------------------------------
-- attach some internal signals to the I/O ports
-----------------------------------------------------------
 
-- attach registered SDRAM control signals to SDRAM input pins
(ce_n, ras_n, cas_n, we_n) <= cmd_r; -- SDRAM operation control bits
dqmh <= dqmh_r;
dqml <= dqml_r;
cke <= cke_r; -- SDRAM clock enable
ba <= ba_r; -- SDRAM bank address
sAddr <= sAddr_r; -- SDRAM address
sDOut <= sData_r; -- SDRAM output data bus
if sDataDir_r = OUTPUT then
sDOutEn <= YES;
else
sDOutEn <= NO; -- output databus enable
end if;
-- attach some port signals
hDOut <= hDOut_r; -- data back to host
opBegun <= opBegun_r; -- true if requested operation has begun
end process;
 
 
-----------------------------------------------------------
-- compute the next state and outputs
-----------------------------------------------------------
 
combinatorial : process(rd, wr, hAddr, hDIn, hDOut_r, sDIn, state_r, opBegun_x,
activeFlag_r, activeRow_r, rdPipeline_r, wrPipeline_r,
hDOutOppPhase_r, nopCntr_r, lock, rfshCntr_r, timer_r, rasTimer_r,
wrTimer_r, refTimer_r, cmd_r, uds, lds, cke_r, activeBank_r, ba_r )
begin
 
-----------------------------------------------------------
-- setup default values for signals
-----------------------------------------------------------
 
opBegun_x <= NO; -- no operations have begun
earlyOpBegun <= opBegun_x;
cke_x <= YES; -- enable SDRAM clock
cmd_x <= NOP_CMD; -- set SDRAM command to no-operation
dqmh_x <= '0';
dqml_x <= '0';
sDataDir_x <= INPUT; -- accept data from the SDRAM
sData_x <= hDIn(sData_x'range); -- output data from host to SDRAM
state_x <= state_r; -- reload these registers and flags
activeFlag_x <= activeFlag_r; -- with their existing values
activeRow_x <= activeRow_r;
activeBank_x <= activeBank_r;
rfshCntr_x <= rfshCntr_r;
 
-----------------------------------------------------------
-- setup default value for the SDRAM address
-----------------------------------------------------------
 
-- extract bank field from host address
ba_x <= hAddr(ba'length + ROW_LEN + COL_LEN - 1 downto ROW_LEN + COL_LEN);
if MULTIPLE_ACTIVE_ROWS = true then
bank <= (others => '0');
bankIndex <= CONV_INTEGER(ba_x);
else
bank <= ba_x;
bankIndex <= 0;
end if;
-- extract row, column fields from host address
row <= hAddr(ROW_LEN + COL_LEN - 1 downto COL_LEN);
-- extend column (if needed) until it is as large as the (SDRAM address bus - 1)
col <= (others => '0'); -- set it to all zeroes
col(COL_LEN-1 downto 0) <= hAddr(COL_LEN-1 downto 0);
-- by default, set SDRAM address to the column address with interspersed
-- command bit set to disable auto-precharge
sAddr_x <= col(col'high downto CMDBIT_POS+1) & AUTO_PCHG_OFF
& col(CMDBIT_POS-1 downto 0);
 
-----------------------------------------------------------
-- manage the read and write operation pipelines
-----------------------------------------------------------
 
-- determine if read operations are in progress by the presence of
-- READ flags in the read pipeline
if rdPipeline_r(rdPipeline_r'high downto 1) /= 0 then
rdInProgress <= YES;
else
rdInProgress <= NO;
end if;
rdPending <= rdInProgress; -- tell the host if read operations are in progress
 
-- enter NOPs into the read and write pipeline shift registers by default
rdPipeline_x <= NOP & rdPipeline_r(rdPipeline_r'high downto 1);
wrPipeline_x(0) <= NOP;
 
-- transfer data from SDRAM to the host data register if a read flag has exited the pipeline
-- (the transfer occurs 1 cycle before we tell the host the read operation is done)
if rdPipeline_r(1) = READ then
hDOutOppPhase_x <= sDIn(hDOut'range); -- gets value on the SDRAM databus on the opposite phase
if IN_PHASE then
-- get the SDRAM data for the host directly from the SDRAM if the controller and SDRAM are in-phase
hDOut_x <= sDIn(hDOut'range);
else
-- otherwise get the SDRAM data that was gathered on the previous opposite clock edge
hDOut_x <= hDOutOppPhase_r(hDOut'range);
end if;
else
-- retain contents of host data registers if no data from the SDRAM has arrived yet
hDOutOppPhase_x <= hDOutOppPhase_r;
hDOut_x <= hDOut_r;
end if;
 
done <= rdPipeline_r(0) or wrPipeline_r(0); -- a read or write operation is done
rdDone <= rdPipeline_r(0); -- SDRAM data available when a READ flag exits the pipeline
 
-----------------------------------------------------------
-- manage row activation
-----------------------------------------------------------
 
-- request a row activation operation if the row of the current address
-- does not match the currently active row in the bank, or if no row
-- in the bank is currently active
if (bank /= activeBank_r) or (row /= activeRow_r(bankIndex)) or (activeFlag_r(bankIndex) = NO) then
doActivate <= YES;
else
doActivate <= NO;
end if;
 
-----------------------------------------------------------
-- manage self-refresh
-----------------------------------------------------------
 
-- enter self-refresh if neither a read or write is requested for MAX_NOP consecutive cycles.
if (rd = YES) or (wr = YES) then
-- any read or write resets NOP counter and exits self-refresh state
nopCntr_x <= 0;
doSelfRfsh <= NO;
elsif nopCntr_r /= MAX_NOP then
-- increment NOP counter whenever there is no read or write operation
nopCntr_x <= nopCntr_r + 1;
doSelfRfsh <= NO;
else
-- start self-refresh when counter hits maximum NOP count and leave counter unchanged
nopCntr_x <= nopCntr_r;
doSelfRfsh <= YES;
end if;
 
-----------------------------------------------------------
-- update the timers
-----------------------------------------------------------
 
-- row activation timer
if rasTimer_r /= 0 then
-- decrement a non-zero timer and set the flag
-- to indicate the row activation is still inprogress
rasTimer_x <= rasTimer_r - 1;
activateInProgress <= YES;
else
-- on timeout, keep the timer at zero and reset the flag
-- to indicate the row activation operation is done
rasTimer_x <= rasTimer_r;
activateInProgress <= NO;
end if;
 
-- write operation timer
if wrTimer_r /= 0 then
-- decrement a non-zero timer and set the flag
-- to indicate the write operation is still inprogress
wrTimer_x <= wrTimer_r - 1;
wrInPRogress <= YES;
else
-- on timeout, keep the timer at zero and reset the flag that
-- indicates a write operation is in progress
wrTimer_x <= wrTimer_r;
wrInPRogress <= NO;
end if;
 
-- refresh timer
if refTimer_r /= 0 then
refTimer_x <= refTimer_r - 1;
else
-- on timeout, reload the timer with the interval between row refreshes
-- and increment the counter for the number of row refreshes that are needed
refTimer_x <= REF_CYCLES;
rfshCntr_x <= rfshCntr_r + 1;
end if;
 
-- main timer for sequencing SDRAM operations
if timer_r /= 0 then
-- decrement the timer and do nothing else since the previous operation has not completed yet.
timer_x <= timer_r - 1;
status <= "0000";
else
-- the previous operation has completed once the timer hits zero
timer_x <= timer_r; -- by default, leave the timer at zero
 
-----------------------------------------------------------
-- compute the next state and outputs
-----------------------------------------------------------
case state_r is
 
-----------------------------------------------------------
-- let clock stabilize and then wait for the SDRAM to initialize
-----------------------------------------------------------
when INITWAIT =>
if lock = YES then
-- wait for SDRAM power-on initialization once the clock is stable
timer_x <= INIT_CYCLES; -- set timer for initialization duration
state_x <= INITPCHG;
else
-- disable SDRAM clock and return to this state if the clock is not stable
-- this insures the clock is stable before enabling the SDRAM
-- it also insures a clean startup if the SDRAM is currently in self-refresh mode
cke_x <= NO;
end if;
status <= "0001";
 
-----------------------------------------------------------
-- precharge all SDRAM banks after power-on initialization
-----------------------------------------------------------
when INITPCHG =>
cmd_x <= PCHG_CMD;
dqmh_x <= '1';
dqml_x <= '1';
sAddr_x(CMDBIT_POS) <= ALL_BANKS; -- precharge all banks
timer_x <= RP_CYCLES; -- set timer for precharge operation duration
rfshCntr_x <= RFSH_OPS; -- set counter for refresh ops needed after precharge
state_x <= INITRFSH;
status <= "0010";
 
-----------------------------------------------------------
-- refresh the SDRAM a number of times after initial precharge
-----------------------------------------------------------
when INITRFSH =>
cmd_x <= RFSH_CMD;
dqmh_x <= '1';
dqml_x <= '1';
timer_x <= RFC_CYCLES; -- set timer to refresh operation duration
rfshCntr_x <= rfshCntr_r - 1; -- decrement refresh operation counter
if rfshCntr_r = 1 then
state_x <= INITSETMODE; -- set the SDRAM mode once all refresh ops are done
end if;
status <= "0011";
 
-----------------------------------------------------------
-- set the mode register of the SDRAM
-----------------------------------------------------------
when INITSETMODE =>
cmd_x <= MODE_CMD;
dqmh_x <= '1';
dqml_x <= '1';
sAddr_x <= MODE; -- output mode register bits on the SDRAM address bits
timer_x <= MODE_CYCLES; -- set timer for mode setting operation duration
state_x <= RW;
status <= "0100";
 
-----------------------------------------------------------
-- process read/write/refresh operations after initialization is done
-----------------------------------------------------------
when RW =>
-----------------------------------------------------------
-- highest priority operation: row refresh
-- do a refresh operation if the refresh counter is non-zero
-----------------------------------------------------------
if rfshCntr_r /= 0 then
-- wait for any row activations, writes or reads to finish before doing a precharge
if (activateInProgress = NO) and (wrInProgress = NO) and (rdInProgress = NO) then
cmd_x <= PCHG_CMD; -- initiate precharge of the SDRAM
dqmh_x <= '1';
dqml_x <= '1';
sAddr_x(CMDBIT_POS) <= ALL_BANKS; -- precharge all banks
timer_x <= RP_CYCLES; -- set timer for this operation
activeFlag_x <= (others => NO); -- all rows are inactive after a precharge operation
state_x <= REFRESHROW; -- refresh the SDRAM after the precharge
end if;
status <= "0101";
-----------------------------------------------------------
-- do a host-initiated read operation
-----------------------------------------------------------
elsif rd = YES then
-- Wait one clock cycle if the bank address has just changed and each bank has its own active row.
-- This gives extra time for the row activation circuitry.
if (ba_x = ba_r) or (MULTIPLE_ACTIVE_ROWS=false) then
-- activate a new row if the current read is outside the active row or bank
if doActivate = YES then
-- activate new row only if all previous activations, writes, reads are done
if (activateInProgress = NO) and (wrInProgress = NO) and (rdInProgress = NO) then
cmd_x <= PCHG_CMD; -- initiate precharge of the SDRAM
dqmh_x <= '1';
dqml_x <= '1';
sAddr_x(CMDBIT_POS) <= ONE_BANK; -- precharge this bank
timer_x <= RP_CYCLES; -- set timer for this operation
activeFlag_x(bankIndex) <= NO; -- rows in this bank are inactive after a precharge operation
state_x <= ACTIVATE; -- activate the new row after the precharge is done
end if;
-- read from the currently active row if no previous read operation
-- is in progress or if pipeline reads are enabled
-- we can always initiate a read even if a write is already in progress
elsif (rdInProgress = NO) or PIPE_EN then
cmd_x <= READ_CMD; -- initiate a read of the SDRAM
-- insert a flag into the pipeline shift register that will exit the end
-- of the shift register when the data from the SDRAM is available
dqmh_x <= not uds;
dqml_x <= not lds;
rdPipeline_x <= READ & rdPipeline_r(rdPipeline_r'high downto 1);
opBegun_x <= YES; -- tell the host the requested operation has begun
end if;
end if;
status <= "0110";
-----------------------------------------------------------
-- do a host-initiated write operation
-----------------------------------------------------------
elsif wr = YES then
-- Wait one clock cycle if the bank address has just changed and each bank has its own active row.
-- This gives extra time for the row activation circuitry.
if (ba_x = ba_r) or (MULTIPLE_ACTIVE_ROWS=false) then
-- activate a new row if the current write is outside the active row or bank
if doActivate = YES then
-- activate new row only if all previous activations, writes, reads are done
if (activateInProgress = NO) and (wrInProgress = NO) and (rdInProgress = NO) then
cmd_x <= PCHG_CMD; -- initiate precharge of the SDRAM
dqmh_x <= '1';
dqml_x <= '1';
sAddr_x(CMDBIT_POS) <= ONE_BANK; -- precharge this bank
timer_x <= RP_CYCLES; -- set timer for this operation
activeFlag_x(bankIndex) <= NO; -- rows in this bank are inactive after a precharge operation
state_x <= ACTIVATE; -- activate the new row after the precharge is done
end if;
-- write to the currently active row if no previous read operations are in progress
elsif rdInProgress = NO then
cmd_x <= WRITE_CMD; -- initiate the write operation
dqmh_x <= not uds;
dqml_x <= not lds;
sDataDir_x <= OUTPUT; -- turn on drivers to send data to SDRAM
-- set timer so precharge doesn't occur too soon after write operation
wrTimer_x <= WR_CYCLES;
-- insert a flag into the 1-bit pipeline shift register that will exit on the
-- next cycle. The write into SDRAM is not actually done by that time, but
-- this doesn't matter to the host
wrPipeline_x(0) <= WRITE;
opBegun_x <= YES; -- tell the host the requested operation has begun
end if;
end if;
status <= "0111";
-----------------------------------------------------------
-- do a host-initiated self-refresh operation
-----------------------------------------------------------
elsif doSelfRfsh = YES then
-- wait until all previous activations, writes, reads are done
if (activateInProgress = NO) and (wrInProgress = NO) and (rdInProgress = NO) then
cmd_x <= PCHG_CMD; -- initiate precharge of the SDRAM
dqmh_x <= '1';
dqml_x <= '1';
sAddr_x(CMDBIT_POS) <= ALL_BANKS; -- precharge all banks
timer_x <= RP_CYCLES; -- set timer for this operation
activeFlag_x <= (others => NO); -- all rows are inactive after a precharge operation
state_x <= SELFREFRESH; -- self-refresh the SDRAM after the precharge
end if;
status <= "1000";
-----------------------------------------------------------
-- no operation
-----------------------------------------------------------
else
state_x <= RW; -- continue to look for SDRAM operations to execute
status <= "1001";
end if;
 
-----------------------------------------------------------
-- activate a row of the SDRAM
-----------------------------------------------------------
when ACTIVATE =>
cmd_x <= ACTIVE_CMD;
dqmh_x <= '0';
dqml_x <= '0';
sAddr_x <= (others => '0'); -- output the address for the row to be activated
sAddr_x(row'range) <= row;
activeBank_x <= bank;
activeRow_x(bankIndex) <= row; -- store the new active SDRAM row address
activeFlag_x(bankIndex) <= YES; -- the SDRAM is now active
rasTimer_x <= RAS_CYCLES; -- minimum time before another precharge can occur
timer_x <= RCD_CYCLES; -- minimum time before a read/write operation can occur
state_x <= RW; -- return to do read/write operation that initiated this activation
status <= "1010";
 
-----------------------------------------------------------
-- refresh a row of the SDRAM
-----------------------------------------------------------
when REFRESHROW =>
cmd_x <= RFSH_CMD;
dqmh_x <= '1';
dqml_x <= '1';
timer_x <= RFC_CYCLES; -- refresh operation interval
rfshCntr_x <= rfshCntr_r - 1; -- decrement the number of needed row refreshes
state_x <= RW; -- process more SDRAM operations after refresh is done
status <= "1011";
 
-----------------------------------------------------------
-- place the SDRAM into self-refresh and keep it there until further notice
-----------------------------------------------------------
when SELFREFRESH =>
if (doSelfRfsh = YES) or (lock = NO) then
-- keep the SDRAM in self-refresh mode as long as requested and until there is a stable clock
cmd_x <= RFSH_CMD; -- output the refresh command; this is only needed on the first clock cycle
dqmh_x <= '1';
dqml_x <= '1';
cke_x <= NO; -- disable the SDRAM clock
else
-- else exit self-refresh mode and start processing read and write operations
cke_x <= YES; -- restart the SDRAM clock
rfshCntr_x <= 0; -- no refreshes are needed immediately after leaving self-refresh
activeFlag_x <= (others => NO); -- self-refresh deactivates all rows
timer_x <= XSR_CYCLES; -- wait this long until read and write operations can resume
state_x <= RW;
end if;
status <= "1100";
 
-----------------------------------------------------------
-- unknown state
-----------------------------------------------------------
when others =>
state_x <= INITWAIT; -- reset state if in erroneous state
status <= "1101";
 
end case;
end if;
end process combinatorial;
 
 
-----------------------------------------------------------
-- update registers on the appropriate clock edge
-----------------------------------------------------------
 
update : process(rst, clk)
begin
 
if rst = YES then
-- asynchronous reset
state_r <= INITWAIT;
activeFlag_r <= (others => NO);
rfshCntr_r <= 0;
timer_r <= 0;
refTimer_r <= REF_CYCLES;
rasTimer_r <= 0;
wrTimer_r <= 0;
nopCntr_r <= 0;
opBegun_r <= NO;
rdPipeline_r <= (others => '0');
wrPipeline_r <= (others => '0');
cke_r <= NO;
cmd_r <= NOP_CMD;
dqmh_r <= '1';
dqml_r <= '1';
ba_r <= (others => '0');
sAddr_r <= (others => '0');
sData_r <= (others => '0');
sDataDir_r <= INPUT;
hDOut_r <= (others => '0');
elsif rising_edge(clk) then
state_r <= state_x;
activeBank_r <= activeBank_x;
activeRow_r <= activeRow_x;
activeFlag_r <= activeFlag_x;
rfshCntr_r <= rfshCntr_x;
timer_r <= timer_x;
refTimer_r <= refTimer_x;
rasTimer_r <= rasTimer_x;
wrTimer_r <= wrTimer_x;
nopCntr_r <= nopCntr_x;
opBegun_r <= opBegun_x;
rdPipeline_r <= rdPipeline_x;
wrPipeline_r <= wrPipeline_x;
cke_r <= cke_x;
cmd_r <= cmd_x;
dqmh_r <= dqmh_x;
dqml_r <= dqml_x;
ba_r <= ba_x;
sAddr_r <= sAddr_x;
sData_r <= sData_x;
sDataDir_r <= sDataDir_x;
hDOut_r <= hDOut_x;
end if;
 
-- the register that gets data from the SDRAM and holds it for the host
-- is clocked on the opposite edge. We don't use this register if IN_PHASE=TRUE.
if rst = YES then
hDOutOppPhase_r <= (others => '0');
elsif falling_edge(clk) then
hDOutOppPhase_r <= hDOutOppPhase_x;
end if;
 
end process update;
 
end arch;
 
 
 
 
--------------------------------------------------------------------
-- Company : XESS Corp.
-- Engineer : Dave Vanden Bout
-- Creation Date : 06/01/2005
-- Copyright : 2005, XESS Corp
-- Tool Versions : WebPACK 6.3.03i
--
-- Description:
-- Dual-port front-end for SDRAM controller. Supports two
-- independent I/O ports to the SDRAM.
--
-- Revision:
-- 1.2.0:
-- added upper and lower data strobe
-- John Kent - 2008-03-23
--
-- 1.0.0
-- Dave Vanden Bout - 2005-01-06
--
-- Additional Comments:
--
-- License:
-- This code can be freely distributed and modified as long as
-- this header is not removed.
--------------------------------------------------------------------
 
library IEEE, UNISIM;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;
use IEEE.numeric_std.all;
use WORK.common.all;
 
entity dualport is
generic(
PIPE_EN : boolean := false; -- enable pipelined read operations
PORT_TIME_SLOTS : std_logic_vector(15 downto 0) := "1111000011110000";
DATA_WIDTH : natural := 16; -- host & SDRAM data width
HADDR_WIDTH : natural := 23 -- host-side address width
);
port(
clk : in std_logic; -- master clock
 
-- host-side port 0
rst0 : in std_logic; -- reset
rd0 : in std_logic; -- initiate read operation
wr0 : in std_logic; -- initiate write operation
uds0 : in std_logic; -- upper data strobe
lds0 : in std_logic; -- lower data strobe
earlyOpBegun0 : out std_logic; -- read/write op has begun (async)
opBegun0 : out std_logic; -- read/write op has begun (clocked)
rdPending0 : out std_logic; -- true if read operation(s) are still in the pipeline
done0 : out std_logic; -- read or write operation is done
rdDone0 : out std_logic; -- read operation is done and data is available
hAddr0 : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host to SDRAM
hDIn0 : in std_logic_vector(DATA_WIDTH-1 downto 0); -- data from host to SDRAM
hDOut0 : out std_logic_vector(DATA_WIDTH-1 downto 0); -- data from SDRAM to host
status0 : out std_logic_vector(3 downto 0); -- diagnostic status of the SDRAM controller FSM
 
-- host-side port 1
rst1 : in std_logic;
rd1 : in std_logic;
wr1 : in std_logic;
uds1 : in std_logic; -- upper data strobe
lds1 : in std_logic; -- lower data strobe
earlyOpBegun1 : out std_logic;
opBegun1 : out std_logic;
rdPending1 : out std_logic;
done1 : out std_logic;
rdDone1 : out std_logic;
hAddr1 : in std_logic_vector(HADDR_WIDTH-1 downto 0);
hDIn1 : in std_logic_vector(DATA_WIDTH-1 downto 0);
hDOut1 : out std_logic_vector(DATA_WIDTH-1 downto 0);
status1 : out std_logic_vector(3 downto 0);
 
-- SDRAM controller port
rst : out std_logic;
rd : out std_logic;
wr : out std_logic;
uds : out std_logic; -- upper data strobe
lds : out std_logic; -- lower data strobe
earlyOpBegun : in std_logic;
opBegun : in std_logic;
rdPending : in std_logic;
done : in std_logic;
rdDone : in std_logic;
hAddr : out std_logic_vector(HADDR_WIDTH-1 downto 0);
hDIn : out std_logic_vector(DATA_WIDTH-1 downto 0);
hDOut : in std_logic_vector(DATA_WIDTH-1 downto 0);
status : in std_logic_vector(3 downto 0)
);
end dualport;
 
 
 
architecture arch of dualport is
-- The door signal controls whether the read/write signal from the active port
-- is allowed through to the read/write inputs of the SDRAM controller.
type doorState is (OPENED, CLOSED);
signal door_r, door_x : doorState;
 
-- The port signal indicates which port is connected to the SDRAM controller.
type portState is (PORT0, PORT1);
signal port_r, port_x : portState;
 
signal switch : std_logic; -- indicates that the active port should be switched
signal inProgress : std_logic; -- the active port has a read/write op in-progress
signal rd_i : std_logic; -- read signal to the SDRAM controller (internal copy)
signal wr_i : std_logic; -- write signal to the SDRAM controller (internal copy)
signal earlyOpBegun0_i, earlyOpBegun1_i : std_logic; -- (internal copies)
signal slot_r, slot_x : std_logic_vector(PORT_TIME_SLOTS'range); -- time-slot allocation shift-register
begin
 
assign_dual_ports : process( port_r, hAddr0, hAddr1, hDIn0, hDIn1, uds0, uds1, lds0, lds1,
hDout, status, rst0, rst1, rd0, rd1, wr0, wr1, door_r,
earlyOpBegun, earlyOpBegun0_i, earlyOpBegun1_i,
rdPending, Done, rdDone, rd_i, wr_i, slot_r )
begin
----------------------------------------------------------------------------
-- multiplex the SDRAM controller port signals to/from the dual host-side ports
----------------------------------------------------------------------------
 
-- send the SDRAM controller the address and data from the currently active port
if port_r = PORT0 then
hAddr <= hAddr0;
hDIn <= hDIn0;
uds <= uds0;
lds <= lds0;
-- send the SDRAM controller status to the active port and give the inactive port an inactive status code
status0 <= status;
status1 <= "1111";
-- apply the read and write signals from the active port to the SDRAM controller only if the door is open.
if door_r = OPENED then
rd_i <= rd0;
wr_i <= wr0;
else
rd_i <= NO;
wr_i <= NO;
end if;
earlyOpBegun0_i <= earlyOpBegun;
earlyOpBegun1_i <= NO;
rdPending0 <= rdPending;
rdPending1 <= NO;
done0 <= done;
done1 <= NO;
rdDone0 <= rdDone;
rdDone1 <= NO;
else
hAddr <= hAddr1;
hDIn <= hDIn1;
uds <= uds1;
lds <= lds1;
-- send the SDRAM controller status to the active port and give the inactive port an inactive status code
status0 <= "1111";
status1 <= status;
-- apply the read and write signals from the active port to the SDRAM controller only if the door is open.
if door_r = OPENED then
rd_i <= rd1;
wr_i <= wr1;
else
rd_i <= NO;
wr_i <= NO;
end if;
earlyOpBegun0_i <= NO;
earlyOpBegun1_i <= earlyOpBegun;
rdPending0 <= NO;
rdPending1 <= rdPending;
done0 <= NO;
done1 <= done;
rdDone0 <= NO;
rdDone1 <= rdDone;
end if;
 
-- both ports get the data from the SDRAM but only the active port will use it
hDOut0 <= hDOut;
hDOut1 <= hDOut;
 
 
-- either port can reset the SDRAM controller
rst <= rst0 or rst1;
 
rd <= rd_i;
wr <= wr_i;
 
----------------------------------------------------------------------------
-- Indicate when the active port needs to be switched. A switch occurs if
-- a read or write operation is requested on the port that is not currently active and:
-- 1) no R/W operation is being performed on the active port or
-- 2) a R/W operation is in progress on the active port, but the time-slot allocation
-- register is giving precedence to the inactive port. (The R/W operation on the
-- active port will be completed before the switch is made.)
-- This rule keeps the active port from hogging all the bandwidth.
----------------------------------------------------------------------------
 
if port_r = PORT0 then
if (((rd0 = NO) and (wr0 = NO)) or (slot_r(0) = '1')) then
switch <= (rd1 or wr1);
else
switch <= NO;
end if;
else
if (((rd1 = NO) and (wr1 = NO)) or (slot_r(0) = '0')) then
switch <= (rd0 or wr0);
else
switch <= NO;
end if;
end if;
-- send the status signals for various SDRAM controller operations back to the active port
earlyOpBegun0 <= earlyOpBegun0_i;
earlyOpBegun1 <= earlyOpBegun1_i;
 
----------------------------------------------------------------------------
-- Indicate when an operation on the active port is in-progress and
-- can't be interrupted by a switch to the other port. (Only read operations
-- are looked at since write operations always complete in one cycle once they
-- are initiated.)
----------------------------------------------------------------------------
inProgress <= rdPending or (rd_i and earlyOpBegun);
 
----------------------------------------------------------------------------
-- Update the time-slot allocation shift-register. The port with priority is indicated by the
-- least-significant bit of the register. The register is rotated right if:
-- 1) the current R/W operation has started, and
-- 2) both ports are requesting R/W operations (indicating contention), and
-- 3) the currently active port matches the port that currently has priority.
-- Under these conditions, the current time slot port allocation has been used so
-- the shift register is rotated right to bring the next port time-slot allocation
-- bit into play.
----------------------------------------------------------------------------
if (earlyOpBegun = YES) and
( ((rd0 = YES) or (wr0 = YES)) and ((rd1 = YES) or (wr1 = YES)) ) and
( ((port_r = PORT0) and (slot_r(0) = '0')) or ((port_r = PORT1) and (slot_r(0) = '1')) ) then
slot_x <= slot_r(0) & slot_r(slot_r'high downto 1);
else
slot_x <= slot_r;
end if;
 
end process;
 
----------------------------------------------------------------------------
-- Determine which port will be active on the next cycle. The active port is switched if:
-- 1) the currently active port has finished its current R/W operation, and
-- 2) there are no pending operations in progress, and
-- 3) the port switch indicator is active.
----------------------------------------------------------------------------
port_process : process(port_r, inProgress, switch, done)
begin
port_x <= port_r; -- by default, the active port is not changed
case port_r is
when PORT0 =>
if (inProgress = NO) and (switch = YES) and (PIPE_EN or (done = YES)) then
port_x <= PORT1;
end if;
when PORT1 =>
if (inProgress = NO) and (switch = YES) and (PIPE_EN or (done = YES)) then
port_x <= PORT0;
end if;
when others =>
port_x <= port_r;
end case;
end process port_process;
 
-----------------------------------------------------------
-- Determine if the door is open for the active port to initiate new R/W operations to
-- the SDRAM controller. If the door is open and R/W operations are in progress but
-- a switch to the other port is indicated, then the door is closed to prevent any
-- further R/W operations from the active port. The door is re-opened once all
-- in-progress operations are completed, at which time the switch to the other port
-- is also completed so it can issue its own R/W commands.
-----------------------------------------------------------
door_process : process(door_r, inProgress, switch)
begin
door_x <= door_r; -- by default, the door remains as it is
case door_r is
when OPENED =>
if (inProgress = YES) and (switch = YES) then
door_x <= CLOSED;
end if;
when CLOSED =>
if inProgress = NO then
door_x <= OPENED;
end if;
when others =>
door_x <= door_r;
end case;
end process door_process;
 
-----------------------------------------------------------
-- update registers on the appropriate clock edge
-----------------------------------------------------------
update : process(rst0, rst1, clk)
begin
if (rst0 = YES) or (rst1 = YES) then
-- asynchronous reset
door_r <= CLOSED;
port_r <= PORT0;
slot_r <= PORT_TIME_SLOTS;
opBegun0 <= NO;
opBegun1 <= NO;
elsif rising_edge(clk) then
door_r <= door_x;
port_r <= port_x;
slot_r <= slot_x;
-- opBegun signals are cycle-delayed versions of earlyOpBegun signals.
-- We can't use the actual opBegun signal from the SDRAM controller
-- because it would be turned off if the active port was switched on the
-- cycle immediately after earlyOpBegun went active.
opBegun0 <= earlyOpBegun0_i;
opBegun1 <= earlyOpBegun1_i;
end if;
end process update;
 
end arch;
/trunk/rtl/System09_Xess_XSA-3S1000/XSA-3S1000.ucf
160,14 → 160,14
#
# Status LED
#
#net S<0> loc=M6 | IOSTANDARD = LVCMOS33 ; # FPGA_D7, LED_D
#net S<1> loc=M11 | IOSTANDARD = LVCMOS33 ; # FPGA_D0, LED_C
#net S<2> loc=N6 | IOSTANDARD = LVCMOS33 ; # FPGA_D6, LED_E
#net S<3> loc=R7 | IOSTANDARD = LVCMOS33 ; # FPGA_D5, LED_G
#net S<4> loc=P10 | IOSTANDARD = LVCMOS33 ; # FPGA_D2, LED_B
#net S<5> loc=T7 | IOSTANDARD = LVCMOS33 ; # FPGA_D4, LED_F
#net S<6> loc=R10 | IOSTANDARD = LVCMOS33 ; # FPGA_D3, LED_A
#net S<7> loc=N11 | IOSTANDARD = LVCMOS33 ; # FPGA_D1, LED_DP
net S<0> loc=M6 | IOSTANDARD = LVCMOS33 ; # FPGA_D7, LED_D
net S<1> loc=M11 | IOSTANDARD = LVCMOS33 ; # FPGA_D0, LED_C
net S<2> loc=N6 | IOSTANDARD = LVCMOS33 ; # FPGA_D6, LED_E
net S<3> loc=R7 | IOSTANDARD = LVCMOS33 ; # FPGA_D5, LED_G
net S<4> loc=P10 | IOSTANDARD = LVCMOS33 ; # FPGA_D2, LED_B
net S<5> loc=T7 | IOSTANDARD = LVCMOS33 ; # FPGA_D4, LED_F
net S<6> loc=R10 | IOSTANDARD = LVCMOS33 ; # FPGA_D3, LED_A
net S<7> loc=N11 | IOSTANDARD = LVCMOS33 ; # FPGA_D1, LED_DP
#
# Parallel Port
#
/trunk/rtl/System09_Xess_XSA-3S1000/System09_Xess_XSA-3S1000.vhd
138,7 → 138,8
 
entity system09 is
port(
CLKA : in Std_Logic; -- 100MHz Clock input
CLKA : in Std_Logic; -- 100MHz Clock input
-- CLKB : in Std_Logic; -- 50MHz Clock input
SW2_N : in Std_logic; -- Master Reset input (active low)
SW3_N : in Std_logic; -- Non Maskable Interrupt input (active low)
 
160,7 → 161,7
RS232_RTS : out Std_Logic;
 
-- Status 7 segment LED
-- S : out std_logic_vector(7 downto 0);
S : out std_logic_vector(7 downto 0);
 
-- SDRAM side
SDRAM_clkfb : in std_logic; -- feedback SDRAM clock after PCB delays
188,12 → 189,12
ide_cs1_n : out std_logic;
 
-- Ethernet $E140 - $E17F
ether_cs_n : out std_logic;
ether_cs_n : out std_logic;
ether_aen : out std_logic; -- Ethernet address enable not
ether_bhe_n : out std_logic; -- Ethernet bus high enable
ether_clk : in std_logic; -- Ethernet clock
ether_rdy : in std_logic; -- Ethernet ready
ether_irq : in std_logic; -- Ethernet irq - Shared with BAR6
ether_irq : in std_logic; -- Ethernet irq - Shared with BAR6
 
-- Slot 1 $E180 - $E1BF
slot1_cs_n : out std_logic;
202,6 → 203,20
-- Slot 2 $E1C0 - $E1FF
slot2_cs_n : out std_logic;
-- slot2_irq : in std_logic;
 
-- CPU Debug Interface signals
-- cpu_reset_o : out Std_Logic;
-- cpu_clk_o : out Std_Logic;
-- cpu_rw_o : out std_logic;
-- cpu_vma_o : out std_logic;
-- cpu_halt_o : out std_logic;
-- cpu_hold_o : out std_logic;
-- cpu_firq_o : out std_logic;
-- cpu_irq_o : out std_logic;
-- cpu_nmi_o : out std_logic;
-- cpu_addr_o : out std_logic_vector(15 downto 0);
-- cpu_data_in_o : out std_logic_vector(7 downto 0);
-- cpu_data_out_o : out std_logic_vector(7 downto 0);
-- Disable Flash
FLASH_CE_N : out std_logic
215,21 → 230,36
 
-----------------------------------------------------------------------------
-- constants
-----------------------------------------------------------------------------
constant SYS_Clock_Frequency : integer := 50000000; -- FPGA System Clock
constant PIX_Clock_Frequency : integer := 25000000; -- VGA Pixel Clock
constant CPU_Clock_Frequency : integer := 25000000; -- CPU Clock
constant BAUD_Rate : integer := 57600; -- Baud Rate
constant ACIA_Clock_Frequency : integer := BAUD_Rate * 16;
-----------------------------------------------------------------------------
 
-- SDRAM
constant MEM_CLK_FREQ : natural := 100_000; -- operating frequency of Memory in KHz
constant SYS_CLK_DIV : real := 2.0; -- divisor for FREQ (can only be 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 8.0 or 16.0)
constant PIPE_EN : boolean := false; -- if true, enable pipelined read operations
constant MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
constant MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
constant DATA_WIDTH : natural := 16; -- host & SDRAM data width
constant NROWS : natural := 8192; -- number of rows in SDRAM array
constant NCOLS : natural := 512; -- number of columns in SDRAM array
constant HADDR_WIDTH : natural := 24; -- host-side address width
constant SADDR_WIDTH : natural := 13; -- SDRAM-side address width
 
constant SYS_CLK_FREQ : natural := ((MEM_CLK_FREQ*2)/integer(SYS_CLK_DIV*2.0))*1000; -- FPGA System Clock
constant CPU_CLK_FREQ : natural := 25_000_000; -- CPU Clock (Hz)
constant CPU_CLK_DIV : natural := (SYS_CLK_FREQ/CPU_CLK_FREQ);
constant VGA_CLK_FREQ : natural := 25_000_000; -- VGA Pixel Clock
constant VGA_CLK_DIV : natural := ((MEM_CLK_FREQ*1000)/VGA_CLK_FREQ);
constant BAUD_RATE : integer := 57600; -- Baud Rate
constant ACIA_CLK_FREQ : integer := BAUD_RATE * 16;
 
constant TRESET : natural := 300; -- min initialization interval (us)
constant RST_CYCLES : natural := 1+(TRESET*(MEM_CLK_FREQ/1_000)); -- SDRAM power-on initialization interval
 
type hold_state_type is ( hold_release_state, hold_request_state );
 
-----------------------------------------------------------------------------
-- Signals
-----------------------------------------------------------------------------
signal rst_n : Std_logic; -- Master Reset input (active low)
signal nmi_n : Std_logic; -- Non Maskable Interrupt input (active low)
 
-- BOOT ROM
signal rom_cs : Std_logic;
signal rom_data_out : Std_Logic_Vector(7 downto 0);
257,7 → 287,10
-- RAM
signal ram_cs : std_logic; -- memory chip select
signal ram_data_out : std_logic_vector(7 downto 0);
signal ram_rd_req : std_logic; -- ram read request (asynch set on ram read, cleared falling CPU clock edge)
signal ram_wr_req : std_logic; -- ram write request (set on rising CPU clock edge, asynch clear on acknowledge)
signal ram_hold : std_logic; -- hold off slow accesses
signal ram_release : std_logic; -- Release ram hold
 
-- CPU Interface signals
signal cpu_reset : Std_Logic;
314,46 → 347,36
signal slot1_cs : std_logic; -- Expansion slot 1
signal slot2_cs : std_logic; -- Expansion slot 2
 
signal rst_i : std_logic; -- internal reset signal
signal clk_i : std_logic; -- internal master clock signal
signal lock : std_logic; -- SDRAM clock DLL lock indicator
 
-- SDRAM
 
constant FREQ : natural := 100_000; -- operating frequency in KHz
constant CLK_DIV : real := 2.0; -- divisor for FREQ (can only be 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 8.0 or 16.0)
constant PIPE_EN : boolean := false; -- if true, enable pipelined read operations
constant MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
constant MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
constant DATA_WIDTH : natural := 16; -- host & SDRAM data width
constant NROWS : natural := 8192; -- number of rows in SDRAM array
constant NCOLS : natural := 512; -- number of columns in SDRAM array
constant HADDR_WIDTH : natural := 24; -- host-side address width
constant SADDR_WIDTH : natural := 13; -- SDRAM-side address width
 
signal rst_i : std_logic; -- internal reset signal
signal clk_i : std_logic; -- internal master clock signal
signal lock : std_logic; -- SDRAM clock DLL lock indicator
 
-- signals that go through the SDRAM host-side interface
signal opBegun : std_logic; -- SDRAM operation started indicator
signal earlyBegun : std_logic; -- SDRAM operation started indicator
signal ramDone : std_logic; -- SDRAM operation complete indicator
signal rdDone : std_logic; -- SDRAM read operation complete indicator
signal wrDone : std_logic; -- SDRAM write operation complete indicator
signal hAddr : std_logic_vector(HADDR_WIDTH-1 downto 0); -- host address bus
signal hDIn : std_logic_vector(DATA_WIDTH-1 downto 0); -- host-side data to SDRAM
signal hDOut : std_logic_vector(DATA_WIDTH-1 downto 0); -- host-side data from SDRAM
signal hRd : std_logic; -- host-side read control signal
signal hWr : std_logic; -- host-side write control signal
signal rdPending : std_logic; -- read operation pending in SDRAM pipeline
type ram_rd_type is (rd_state0, rd_state1, rd_state2, rd_state3);
type ram_wr_type is (wr_state0, wr_state1, wr_state2, wr_state3, wr_state4);
signal ram_rd_state : ram_rd_type;
signal ram_wr_state : ram_wr_type;
signal opBegun : std_logic; -- SDRAM operation started indicator
signal earlyBegun : std_logic; -- SDRAM operation started indicator
signal ramDone : std_logic; -- SDRAM operation complete indicator
signal rdDone : std_logic; -- SDRAM read operation complete indicator
signal wrDone : std_logic; -- SDRAM write operation complete indicator
signal hAddr : std_logic_vector(HADDR_WIDTH-1 downto 0); -- host address bus
signal hDIn : std_logic_vector(DATA_WIDTH-1 downto 0); -- host-side data to SDRAM
signal hDOut : std_logic_vector(DATA_WIDTH-1 downto 0); -- host-side data from SDRAM
signal hRd : std_logic; -- host-side read control signal
signal hWr : std_logic; -- host-side write control signal
signal hUds : std_logic; -- host-side upper data strobe
signal hLds : std_logic; -- host-side lower data strobe
signal rdPending : std_logic; -- read operation pending in SDRAM pipeline
type ram_type is (ram_state_0,
ram_state_rd1, ram_state_rd2,
ram_state_wr1,
ram_state_3 );
signal ram_state : ram_type;
 
 
-- signal BaudCount : std_logic_vector(5 downto 0);
signal CountL : std_logic_vector(23 downto 0);
signal clk_count : std_logic_vector(0 downto 0);
signal Clk25 : std_logic;
signal pix_clk : std_logic;
-- signal BaudCount : std_logic_vector(5 downto 0);
signal CountL : std_logic_vector(23 downto 0);
signal clk_count : natural range 0 to CPU_CLK_DIV;
signal Clk25 : std_logic;
signal vga_clk : std_logic;
 
-----------------------------------------------------------------
--
366,7 → 389,7
clk: in std_logic;
rst: in std_logic;
vma: out std_logic;
addr: out std_logic_vector(15 downto 0);
addr: out std_logic_vector(15 downto 0);
rw: out std_logic; -- Asynchronous memory interface
data_out: out std_logic_vector(7 downto 0);
data_in: in std_logic_vector(7 downto 0);
449,12 → 472,12
 
component ACIA_Clock
generic (
SYS_CLK_FREQ : integer := SYS_Clock_Frequency;
ACIA_CLK_FREQ : integer := ACIA_Clock_Frequency
SYS_CLK_FREQ : integer := SYS_CLK_FREQ;
ACIA_CLK_FREQ : integer := ACIA_CLK_FREQ
);
port (
clk : in Std_Logic; -- System Clock Input
acia_clk : out Std_logic -- ACIA Clock output
ACIA_clk : out Std_logic -- ACIA Clock output
);
end component;
 
467,7 → 490,7
 
component keyboard
generic(
KBD_CLK_FREQ : integer := CPU_Clock_Frequency
KBD_CLK_FREQ : integer := CPU_CLK_FREQ
);
port(
clk : in std_logic;
490,18 → 513,18
----------------------------------------
component vdu8
generic(
VDU_CLOCK_FREQUENCY : integer := CPU_Clock_Frequency; -- HZ
VGA_CLOCK_FREQUENCY : integer := PIX_Clock_Frequency; -- HZ
VDU_CLK_FREQ : integer := CPU_CLK_FREQ; -- HZ
VGA_CLK_FREQ : integer := VGA_CLK_FREQ; -- HZ
VGA_HOR_CHARS : integer := 80; -- CHARACTERS
VGA_VER_CHARS : integer := 25; -- CHARACTERS
VGA_PIXELS_PER_CHAR : integer := 8; -- PIXELS
VGA_LINES_PER_CHAR : integer := 16; -- LINES
VGA_PIX_PER_CHAR : integer := 8; -- PIXELS
VGA_LIN_PER_CHAR : integer := 16; -- LINES
VGA_HOR_BACK_PORCH : integer := 40; -- PIXELS
VGA_HOR_SYNC : integer := 96; -- PIXELS
VGA_HOR_FRONT_PORCH : integer := 24; -- PIXELS
VGA_VER_BACK_PORCH : integer := 13; -- LINES
VGA_VER_SYNC : integer := 1; -- LINES
VGA_VER_FRONT_PORCH : integer := 36 -- LINES
VGA_VER_SYNC : integer := 2; -- LINES
VGA_VER_FRONT_PORCH : integer := 35 -- LINES
);
port(
-- control register interface
581,11 → 604,12
data_out : out std_logic_vector(7 downto 0)
);
end component;
 
 
component XSASDRAMCntl
generic(
FREQ : natural := FREQ; -- operating frequency in KHz
CLK_DIV : real := CLK_DIV; -- divisor for FREQ (can only be 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 8.0 or 16.0)
FREQ : natural := MEM_CLK_FREQ;-- operating frequency in KHz
CLK_DIV : real := SYS_CLK_DIV; -- divisor for FREQ (can only be 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 8.0 or 16.0)
PIPE_EN : boolean := PIPE_EN; -- if true, enable pipelined read operations
MAX_NOP : natural := MAX_NOP; -- number of NOPs before entering self-refresh
MULTIPLE_ACTIVE_ROWS : boolean := MULTIPLE_ACTIVE_ROWS; -- if true, allow an active row in each bank
605,6 → 629,8
rst : in std_logic; -- reset
rd : in std_logic; -- initiate read operation
wr : in std_logic; -- initiate write operation
uds : in std_logic; -- upper data strobe
lds : in std_logic; -- lower data strobe
earlyOpBegun : out std_logic; -- read/write/self-refresh op begun (async)
opBegun : out std_logic; -- read/write/self-refresh op begun (clocked)
rdPending : out std_logic; -- read operation(s) are still in the pipeline
630,7 → 656,7
dqml : out std_logic -- low databits I/O mask
);
end component;
 
 
--
-- Clock buffer
--
650,7 → 676,7
clk => cpu_clk,
rst => cpu_reset,
vma => cpu_vma,
addr => cpu_addr(15 downto 0),
addr => cpu_addr(15 downto 0),
rw => cpu_rw,
data_out => cpu_data_out,
data_in => cpu_data_in,
687,10 → 713,9
cs => acia_cs,
rw => cpu_rw,
addr => cpu_addr(0),
data_in => cpu_data_out,
data_out => acia_data_out,
data_in => cpu_data_out,
data_out => acia_data_out,
irq => acia_irq,
 
RxC => acia_clk,
TxC => acia_clk,
RxD => rxd,
703,8 → 728,8
 
my_ACIA_Clock : ACIA_Clock
generic map(
SYS_CLK_FREQ => SYS_Clock_Frequency,
ACIA_CLK_FREQ => ACIA_Clock_Frequency
SYS_CLK_FREQ => SYS_CLK_FREQ,
ACIA_CLK_FREQ => ACIA_CLK_FREQ
)
port map(
clk => Clk_i,
718,7 → 743,7
----------------------------------------
my_keyboard : keyboard
generic map (
KBD_CLK_FREQ => CPU_Clock_frequency
KBD_CLK_FREQ => CPU_CLK_FREQ
)
port map(
clk => cpu_clk,
740,18 → 765,18
----------------------------------------
my_vdu : vdu8
generic map(
VDU_CLOCK_FREQUENCY => CPU_Clock_Frequency, -- HZ
VGA_CLOCK_FREQUENCY => PIX_Clock_Frequency, -- HZ
VDU_CLK_FREQ => CPU_CLK_FREQ, -- HZ
VGA_CLK_FREQ => VGA_CLK_FREQ, -- HZ
VGA_HOR_CHARS => 80, -- CHARACTERS
VGA_VER_CHARS => 25, -- CHARACTERS
VGA_PIXELS_PER_CHAR => 8, -- PIXELS
VGA_LINES_PER_CHAR => 16, -- LINES
VGA_PIX_PER_CHAR => 8, -- PIXELS
VGA_LIN_PER_CHAR => 16, -- LINES
VGA_HOR_BACK_PORCH => 40, -- PIXELS
VGA_HOR_SYNC => 96, -- PIXELS
VGA_HOR_FRONT_PORCH => 24, -- PIXELS
VGA_VER_BACK_PORCH => 13, -- LINES
VGA_VER_SYNC => 1, -- LINES
VGA_VER_FRONT_PORCH => 36 -- LINES
VGA_VER_SYNC => 2, -- LINES
VGA_VER_FRONT_PORCH => 35 -- LINES
)
port map(
 
765,7 → 790,7
vdu_data_out => vdu_data_out,
 
-- vga port connections
vga_clk => pix_clk, -- 25 MHz VDU pixel clock
vga_clk => vga_clk, -- 25 MHz VDU pixel clock
vga_red_o => vga_red_o,
vga_green_o => vga_green_o,
vga_blue_o => vga_blue_o,
817,7 → 842,7
data_in => cpu_data_out,
data_out => dat_addr(7 downto 0)
);
 
 
------------------------------------------------------------------------
-- Instantiate the SDRAM controller that connects to the memory tester
-- module and interfaces to the external SDRAM chip.
824,10 → 849,12
------------------------------------------------------------------------
u1 : xsaSDRAMCntl
generic map(
FREQ => FREQ,
PIPE_EN => PIPE_EN,
FREQ => MEM_CLK_FREQ,
CLK_DIV => SYS_CLK_DIV,
PIPE_EN => PIPE_EN,
MAX_NOP => MAX_NOP,
MULTIPLE_ACTIVE_ROWS => MULTIPLE_ACTIVE_ROWS,
DATA_WIDTH => DATA_WIDTH,
MULTIPLE_ACTIVE_ROWS => MULTIPLE_ACTIVE_ROWS,
NROWS => NROWS,
NCOLS => NCOLS,
HADDR_WIDTH => HADDR_WIDTH,
843,6 → 870,8
rst => rst_i, -- reset
rd => hRd, -- host-side SDRAM read control from memory tester
wr => hWr, -- host-side SDRAM write control from memory tester
uds => hUds, -- host-side SDRAM upper data strobe
lds => hLds, -- host-side SDRAM lower data strobe
rdPending => rdPending,-- read operation to SDRAM is in progress
opBegun => opBegun, -- indicates memory read/write has begun
earlyOpBegun => earlyBegun, -- early indicator that memory operation has begun
866,17 → 895,17
dqmh => SDRAM_dqmh, -- SDRAM DQMH
dqml => SDRAM_dqml -- SDRAM DQML
);
 
 
cpu_clk_buffer : BUFG port map(
i => Clk25,
o => cpu_clk
);
 
pix_clk_buffer : BUFG port map(
vga_clk_buffer : BUFG port map(
i => Clk25,
o => pix_clk
o => vga_clk
);
----------------------------------------------------------------------
--
-- Process to decode memory map
883,8 → 912,7
--
----------------------------------------------------------------------
 
mem_decode: process( cpu_clk,
cpu_addr, cpu_rw, cpu_vma,
mem_decode: process( cpu_addr, cpu_rw, cpu_vma,
dat_addr,
rom_data_out,
flex_data_out,
1057,7 → 1085,8
-- ISA bus little endian
-- Not sure about IDE interface
--
peripheral_bus: process( clk_i, cpu_reset, cpu_rw, cpu_addr, cpu_data_out )
peripheral_bus: process( clk_i, cpu_reset, cpu_rw, cpu_addr, cpu_data_out,
pb_cs, pb_wreg, pb_rreg )
begin
pb_wru <= pb_cs and (not cpu_rw) and (not cpu_addr(0));
pb_wrl <= pb_cs and (not cpu_rw) and cpu_addr(0) ;
1128,13 → 1157,13
--
-- Hold Peripheral bus accesses for a few cycles
--
peripheral_bus_hold: process( cpu_clk, cpu_reset, pb_rdu, pb_wrl, ether_rdy )
peripheral_bus_hold: process( cpu_clk, cpu_reset, pb_rdu, pb_wrl ) --, ether_rdy )
begin
if cpu_reset = '1' then
pb_release <= '0';
pb_count <= "0000";
pb_hold_state <= hold_release_state;
elsif cpu_clk'event and cpu_clk='1' then
elsif rising_edge(cpu_clk) then
--
-- The perpheral bus hold signal should be generated on
-- 16 bit bus read which will be on even byte reads or
1153,10 → 1182,10
 
when hold_request_state =>
if pb_count = "0000" then
if ether_rdy = '1' then
-- if ether_rdy = '1' then
pb_release <= '1';
pb_hold_state <= hold_release_state;
end if;
-- end if;
else
pb_count <= pb_count - "0001";
end if;
1179,10 → 1208,9
--
-- Interrupts and other bus control signals
--
interrupts : process( lock, rst_n, nmi_n,
pb_cs, pb_hold, pb_release,
ram_cs, ram_hold,
ether_irq,
interrupts : process( SW3_N,
pb_cs, pb_hold, pb_release, ram_hold,
-- ether_irq,
acia_irq,
keyboard_irq,
trap_irq,
1189,13 → 1217,13
timer_irq
)
begin
cpu_reset <= (not rst_n) or (not lock); -- CPU reset is active high
pb_hold <= pb_cs and (not pb_release);
cpu_irq <= acia_irq or keyboard_irq;
cpu_nmi <= trap_irq or not( nmi_n );
cpu_firq <= timer_irq;
cpu_halt <= '0';
cpu_hold <= pb_hold or ram_hold;
pb_hold <= pb_cs and (not pb_release);
cpu_irq <= acia_irq or keyboard_irq;
cpu_nmi <= trap_irq or not( SW3_N );
cpu_firq <= timer_irq;
cpu_halt <= '0';
cpu_hold <= pb_hold or ram_hold;
FLASH_CE_N <= '1';
end process;
 
 
1202,11 → 1230,11
--
-- Flash 7 segment LEDS
--
my_led_flasher: process( Clk_i, rst_n, CountL )
my_led_flasher: process( clk_i, rst_i, CountL )
begin
if rst_n = '0' then
if rst_i = '1' then
CountL <= "000000000000000000000000";
elsif(Clk_i'event and Clk_i = '1') then
elsif rising_edge(clk_i) then
CountL <= CountL + 1;
end if;
-- S(7 downto 0) <= CountL(23 downto 16);
1213,28 → 1241,34
end process;
 
--
-- Generate a 25 MHz Clock from 50 MHz
-- Generate CPU & Pixel Clock from Memory Clock
--
my_prescaler : process( Clk_i, clk_count )
my_prescaler : process( clk_i, clk_count )
begin
if Clk_i'event and Clk_i = '1' then
clk_count(0) <= not clk_count(0);
end if;
Clk25 <= clk_count(0);
if rising_edge( clk_i ) then
 
if clk_count = 0 then
clk_count <= CPU_CLK_DIV-1;
else
clk_count <= clk_count - 1;
end if;
 
if clk_count = 0 then
clk25 <= '0';
elsif clk_count = (CPU_CLK_DIV/2) then
clk25 <= '1';
end if;
 
end if;
end process;
 
--
-- Push buttons
-- Reset button and reset timer
--
my_switch_assignments : process( SW2_N, SW3_N, rst_n )
my_switch_assignments : process( rst_i, SW2_N, lock )
begin
rst_n <= SW2_N;
rst_i <= not rst_n;
nmi_n <= SW3_N;
--
-- Disable Flash memory
--
FLASH_CE_N <= '1';
rst_i <= not SW2_N;
cpu_reset <= rst_i or (not lock);
end process;
 
--
1283,125 → 1317,164
VGA_blue(1) <= vga_blue_o;
VGA_blue(2) <= vga_blue_o;
end process;
 
 
--
-- SDRAM assignments
-- SDRAM read write control
--
my_sdram_assignments : process( cpu_clk, clk_i, cpu_reset,
opBegun, rdDone, wrDone,
ram_rd_state, ram_wr_state,
cpu_addr, dat_addr,
cpu_data_out, hDout,
ram_cs, cpu_rw, ram_hold )
my_sdram_rw : process( clk_i, cpu_reset,
opBegun, ramDone,
ram_state,
ram_rd_req, ram_wr_req )
begin
if( cpu_reset = '1' ) then
hWr <= '0';
hRd <= '0';
wrDone <= '0';
ram_wr_state <= wr_state0;
ram_rd_state <= rd_state0;
hRd <= '0';
hWr <= '0';
ram_hold <= '0';
ram_state <= ram_state_0;
 
elsif( clk_i'event and clk_i='0' ) then
elsif( falling_edge(clk_i) ) then
--
-- read state machine
-- ram state machine
--
case ram_rd_state is
case ram_state is
 
when rd_state0 =>
if (ram_hold = '1') and (cpu_rw = '1') then
hRd <= '1';
ram_rd_state <= rd_state1;
when ram_state_0 =>
if ram_rd_req = '1' then
ram_hold <= '1';
hRd <= '1';
ram_state <= ram_state_rd1;
elsif ram_wr_req = '1' then
ram_hold <= '1';
hWr <= '1';
ram_state <= ram_state_wr1;
end if;
 
when rd_state1 =>
when ram_state_rd1 =>
if opBegun = '1' then
ram_rd_state <= rd_state2;
hRd <= '0';
ram_state <= ram_state_rd2;
end if;
 
when rd_state2 =>
if rdDone = '1' then
hRd <= '0';
ram_rd_state <= rd_state3;
when ram_state_rd2 =>
if ramDone = '1' then
ram_hold <= '0';
ram_state <= ram_state_3;
end if;
 
when rd_state3 =>
if rdDone = '0' then
ram_rd_state <= rd_state0;
when ram_state_wr1 =>
if opBegun = '1' then
ram_hold <= '0';
hWr <= '0';
ram_state <= ram_state_3;
end if;
 
when others =>
hRd <= '0';
ram_rd_state <= rd_state0;
end case;
 
--
-- Write state machine
--
case ram_wr_state is
 
when wr_state0 =>
if (ram_hold = '1') and (cpu_rw = '0') then
hWr <= '1';
wrDone <= '0';
ram_wr_state <= wr_state1;
when ram_state_3 =>
if ram_release = '1' then
ram_state <= ram_state_0;
end if;
 
when wr_state1 =>
if opBegun = '1' then
hWr <= '0';
wrDone <= '0';
ram_wr_state <= wr_state2;
end if;
 
when wr_state2 =>
hWr <= '0';
wrDone <= '0';
ram_wr_state <= wr_state3;
 
when wr_state3 =>
hWr <= '0';
wrDone <= '1';
ram_wr_state <= wr_state4;
 
when wr_state4 =>
hWr <= '0';
wrDone <= '0';
ram_wr_state <= wr_state0;
 
when others =>
hWr <= '0';
wrDone <= '0';
ram_wr_state <= wr_state0;
 
hRd <= '0';
hWr <= '0';
ram_hold <= '0';
ram_state <= ram_state_0;
end case;
 
end if;
--
-- Strobe host RD and WR signals high on RAM select
-- Return low when cycle has started
--
if( cpu_reset = '1' ) then
ram_hold <= '0';
elsif( cpu_clk'event and cpu_clk='1' ) then
--
-- Hold is intitiated when the RAM is selected
-- and released when access cycle is complete
--
if (ram_hold = '0') and (ram_cs = '1') then
ram_hold <= '1';
elsif (ram_hold = '1') and ((rdDone = '1') or (wrDone = '1')) then
ram_hold <= '0';
end if;
end if;
end process;
 
--
-- SDRAM Address and data bus assignments
--
my_sdram_addr_data : process( cpu_addr, dat_addr,
cpu_data_out, hDout )
begin
hAddr(23 downto 19) <= "00000";
hAddr(18 downto 11) <= dat_addr;
hAddr(10 downto 0) <= cpu_addr(11 downto 1);
hUds <= not cpu_addr(0);
hLds <= cpu_addr(0);
if cpu_addr(0) = '0' then
hDin( 7 downto 0) <= (others=>'0');
hDin(15 downto 8) <= cpu_data_out;
ram_data_out <= hDout(15 downto 8);
else
hDin( 7 downto 0) <= cpu_data_out;
hDin(15 downto 8) <= (others=>'0');
ram_data_out <= hDout( 7 downto 0);
end if;
end process;
 
--
-- Hold RAM until falling CPU clock edge
--
ram_bus_hold: process( cpu_clk, cpu_reset, ram_hold )
begin
if ram_hold = '1' then
ram_release <= '0';
elsif falling_edge(cpu_clk) then
ram_release <= '1';
end if;
end process;
 
--
-- CPU read data request on rising CPU clock edge
--
ram_read_request: process( hRd, cpu_clk, ram_cs, cpu_rw, ram_release )
begin
if hRd = '1' then
ram_rd_req <= '0';
elsif rising_edge(cpu_clk) then
if (ram_cs = '1') and (cpu_rw = '1') and (ram_release = '1') then
ram_rd_req <= '1';
end if;
end if;
end process;
 
--
-- CPU write data to RAM valid on rising CPU clock edge
--
ram_write_request: process( hWr, cpu_clk, ram_cs, cpu_rw, ram_release )
begin
if hWr = '1' then
ram_wr_req <= '0';
elsif rising_edge(cpu_clk) then
if (ram_cs = '1') and (cpu_rw = '0') and (ram_release = '1') then
ram_wr_req <= '1';
end if;
end if;
end process;
 
 
 
hAddr(23 downto 20) <= "0000";
hAddr(19 downto 12) <= dat_addr;
hAddr(11 downto 0) <= cpu_addr(11 downto 0);
hDin(7 downto 0) <= cpu_data_out;
hDin(15 downto 8) <= (others => '0');
ram_data_out <= hDout(7 downto 0);
status_leds : process( rst_i, cpu_reset, lock )
begin
S(0) <= rst_i;
S(1) <= cpu_reset;
S(2) <= lock;
S(3) <= countL(23);
S(7 downto 4) <= "0000";
end process;
 
--debug_proc : process( cpu_reset, cpu_clk, cpu_rw, cpu_vma,
-- cpu_halt, cpu_hold,
-- cpu_firq, cpu_irq, cpu_nmi,
-- cpu_addr, cpu_data_out, cpu_data_in )
--begin
-- cpu_reset_o <= cpu_reset;
-- cpu_clk_o <= cpu_clk;
-- cpu_rw_o <= cpu_rw;
-- cpu_vma_o <= cpu_vma;
-- cpu_halt_o <= cpu_halt;
-- cpu_hold_o <= cpu_hold;
-- cpu_firq_o <= cpu_firq;
-- cpu_irq_o <= cpu_irq;
-- cpu_nmi_o <= cpu_nmi;
-- cpu_addr_o <= cpu_addr;
-- cpu_data_out_o <= cpu_data_out;
-- cpu_data_in_o <= cpu_data_in;
--end process;
 
end process;
 
end rtl; --===================== End of architecture =======================--
 

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