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-------------------------------------------------------------------- -- 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;
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