--===========================================================================----
|
--===========================================================================----
|
--
|
--
|
-- S Y N T H E Z I A B L E System09 - SOC.
|
-- S Y N T H E Z I A B L E System09 - SOC.
|
--
|
--
|
-- www.OpenCores.Org - February 2007
|
-- www.OpenCores.Org - February 2007
|
-- This core adheres to the GNU public license
|
-- This core adheres to the GNU public license
|
--
|
--
|
-- File name : System09_Xess_XSA-3S1000.vhd
|
-- File name : System09_Xess_XSA-3S1000.vhd
|
--
|
--
|
-- Purpose : Top level file for 6809 compatible system on a chip
|
-- Purpose : Top level file for 6809 compatible system on a chip
|
-- Designed with Xilinx XC3S1000 Spartan 3 FPGA.
|
-- Designed with Xilinx XC3S1000 Spartan 3 FPGA.
|
-- Implemented With XESS XSA-3S1000 FPGA board.
|
-- Implemented With XESS XSA-3S1000 FPGA board.
|
-- *** Note ***
|
-- *** Note ***
|
-- This configuration can run Flex9 however it only has
|
-- This configuration can run Flex9 however it only has
|
-- 32k bytes of user memory and the VDU is monochrome
|
-- 32k bytes of user memory and the VDU is monochrome
|
-- The design needs to be updated to use the SDRAM on
|
-- The design needs to be updated to use the SDRAM on
|
-- the XSA-3S1000 board.
|
-- the XSA-3S1000 board.
|
-- This configuration also lacks a DAT so cannot use
|
-- This configuration also lacks a DAT so cannot use
|
-- the RAM Disk features of SYS09BUG.
|
-- the RAM Disk features of SYS09BUG.
|
--
|
--
|
-- Dependencies : ieee.Std_Logic_1164
|
-- Dependencies : ieee.Std_Logic_1164
|
-- ieee.std_logic_unsigned
|
-- ieee.std_logic_unsigned
|
-- ieee.std_logic_arith
|
-- ieee.std_logic_arith
|
-- ieee.numeric_std
|
-- ieee.numeric_std
|
-- unisim.vcomponents
|
-- unisim.vcomponents
|
--
|
--
|
-- Uses : mon_rom (sys09bug_rom4k_b16.vhd) Sys09Bug Monitor ROM
|
-- Uses : mon_rom (sys09bug_rom4k_b16.vhd) Sys09Bug Monitor ROM
|
-- cpu09 (cpu09.vhd) CPU core
|
-- cpu09 (cpu09.vhd) CPU core
|
-- ACIA_6850 (ACIA_6850.vhd) ACIA / UART
|
-- ACIA_6850 (ACIA_6850.vhd) ACIA / UART
|
-- (ACIA_RX.vhd)
|
-- (ACIA_RX.vhd)
|
-- (ACIA_TX.vhd)
|
-- (ACIA_TX.vhd)
|
-- ACIA_Clock (ACIA_Clock.vhd) ACIA clock.
|
-- ACIA_Clock (ACIA_Clock.vhd) ACIA clock.
|
-- keyboard (keyboard.vhd) PS/2 Keyboard interface
|
-- keyboard (keyboard.vhd) PS/2 Keyboard interface
|
-- (ps2_keyboard.vhd)
|
-- (ps2_keyboard.vhd)
|
-- (keymap_rom_slice.vhd) Key map table
|
-- (keymap_rom_slice.vhd) Key map table
|
-- vdu8_mono (vdu8_mono.vhd) Monochrome VDU
|
-- vdu8_mono (vdu8_mono.vhd) Monochrome VDU
|
-- (char_rom2k_b16.vhd)
|
-- (char_rom2k_b16.vhd)
|
-- (ram2k_b16.vhd)
|
-- (ram2k_b16.vhd)
|
-- timer (timer.vhd) Interrupt timer
|
-- timer (timer.vhd) Interrupt timer
|
-- trap (trap.vhd) Bus condition trap logic
|
-- trap (trap.vhd) Bus condition trap logic
|
-- flex_ram (flex9_ram8k_b16.vhd) Flex operating system
|
-- flex_ram (flex9_ram8k_b16.vhd) Flex operating system
|
-- ram_32K (ram32k_b16.vhd) 32 KBytes of Block RAM
|
-- ram_32K (ram32k_b16.vhd) 32 KBytes of Block RAM
|
--
|
--
|
--
|
--
|
-- Author : John E. Kent
|
-- Author : John E. Kent
|
-- dilbert57@opencores.org
|
-- dilbert57@opencores.org
|
--
|
--
|
-- Memory Map :
|
-- Memory Map :
|
--
|
--
|
-- $0000 - User program RAM (32K Bytes)
|
-- $0000 - User program RAM (32K Bytes)
|
-- $C000 - Flex Operating System memory (8K Bytes)
|
-- $C000 - Flex Operating System memory (8K Bytes)
|
-- $E000 - ACIA (SWTPc)
|
-- $E000 - ACIA (SWTPc)
|
-- $E010 - Reserved for FD1771 FDC (SWTPc)
|
-- $E010 - Reserved for FD1771 FDC (SWTPc)
|
-- $E020 - Keyboard
|
-- $E020 - Keyboard
|
-- $E030 - VDU
|
-- $E030 - VDU
|
-- $E040 - IDE / Compact Flash interface
|
-- $E040 - IDE / Compact Flash interface
|
-- $E050 - Timer
|
-- $E050 - Timer
|
-- $E060 - Bus trap
|
-- $E060 - Bus trap
|
-- $E070 - Reserced for Parallel I/O (B5-X300)
|
-- $E070 - Reserced for Parallel I/O (B5-X300)
|
-- $E080 - Reserved for 6821 PIA (?) (SWTPc)
|
-- $E080 - Reserved for 6821 PIA (?) (SWTPc)
|
-- $E090 - Reserved for 6840 PTM (?) (SWTPc)
|
-- $E090 - Reserved for 6840 PTM (?) (SWTPc)
|
-- $F000 - Sys09Bug monitor Program (4K Bytes)
|
-- $F000 - Sys09Bug monitor Program (4K Bytes)
|
--
|
--
|
--===========================================================================----
|
--===========================================================================----
|
--
|
--
|
-- Revision History:
|
-- Revision History:
|
--===========================================================================--
|
--===========================================================================--
|
-- Version 0.1 - 20 March 2003
|
-- Version 0.1 - 20 March 2003
|
-- Version 0.2 - 30 March 2003
|
-- Version 0.2 - 30 March 2003
|
-- Version 0.3 - 29 April 2003
|
-- Version 0.3 - 29 April 2003
|
-- Version 0.4 - 29 June 2003
|
-- Version 0.4 - 29 June 2003
|
--
|
--
|
-- Version 0.5 - 19 July 2003
|
-- Version 0.5 - 19 July 2003
|
-- prints out "Hello World"
|
-- prints out "Hello World"
|
--
|
--
|
-- Version 0.6 - 5 September 2003
|
-- Version 0.6 - 5 September 2003
|
-- Runs SBUG
|
-- Runs SBUG
|
--
|
--
|
-- Version 1.0- 6 Sep 2003 - John Kent
|
-- Version 1.0- 6 Sep 2003 - John Kent
|
-- Inverted SysClk
|
-- Inverted SysClk
|
-- Initial release to Open Cores
|
-- Initial release to Open Cores
|
--
|
--
|
-- Version 1.1 - 17 Jan 2004 - John Kent
|
-- Version 1.1 - 17 Jan 2004 - John Kent
|
-- Updated miniUart.
|
-- Updated miniUart.
|
--
|
--
|
-- Version 1.2 - 25 Jan 2004 - John Kent
|
-- Version 1.2 - 25 Jan 2004 - John Kent
|
-- removed signals "test_alu" and "test_cc"
|
-- removed signals "test_alu" and "test_cc"
|
-- Trap hardware re-instated.
|
-- Trap hardware re-instated.
|
--
|
--
|
-- Version 1.3 - 11 Feb 2004 - John Kent
|
-- Version 1.3 - 11 Feb 2004 - John Kent
|
-- Designed forked off to produce System09_VDU
|
-- Designed forked off to produce System09_VDU
|
-- Added VDU component
|
-- Added VDU component
|
-- VDU runs at 25MHz and divides the clock by 2 for the CPU
|
-- VDU runs at 25MHz and divides the clock by 2 for the CPU
|
-- UART Runs at 57.6 Kbps
|
-- UART Runs at 57.6 Kbps
|
--
|
--
|
-- Version 2.0 - 2 September 2004 - John Kent
|
-- Version 2.0 - 2 September 2004 - John Kent
|
-- ported to Digilent Xilinx Spartan3 starter board
|
-- ported to Digilent Xilinx Spartan3 starter board
|
-- removed Compact Flash and Trap Logic.
|
-- removed Compact Flash and Trap Logic.
|
-- Replaced SBUG with KBug9s
|
-- Replaced SBUG with KBug9s
|
--
|
--
|
-- Version 3.0 - 29th August 2006 - John Kent
|
-- Version 3.0 - 29th August 2006 - John Kent
|
-- Adapted to XSA-3S1000 board.
|
-- Adapted to XSA-3S1000 board.
|
-- Removed DAT and miniUART.
|
-- Removed DAT and miniUART.
|
-- Used 32KBytes of Block RAM.
|
-- Used 32KBytes of Block RAM.
|
--
|
--
|
-- Version 3.1 - 15th January 2007 - John Kent
|
-- Version 3.1 - 15th January 2007 - John Kent
|
-- Modified vdu8 interface
|
-- Modified vdu8 interface
|
-- Added a clock divider
|
-- Added a clock divider
|
--
|
--
|
-- Version 3.2 - 25th February 2007 - John Kent
|
-- Version 3.2 - 25th February 2007 - John Kent
|
-- reinstated ACIA_6850 and ACIA_Clock
|
-- reinstated ACIA_6850 and ACIA_Clock
|
-- Updated VDU8 & Keyboard with generic parameters
|
-- Updated VDU8 & Keyboard with generic parameters
|
-- Defined Constants for clock speed calculations
|
-- Defined Constants for clock speed calculations
|
--
|
--
|
-- Version 3.3 - 1st July 2007 - John Kent
|
-- Version 3.3 - 1st July 2007 - John Kent
|
-- Made VDU mono to save on one RAMB16
|
-- Made VDU mono to save on one RAMB16
|
-- Used distributed memory for Key Map ROM to save one RAMB16
|
-- Used distributed memory for Key Map ROM to save one RAMB16
|
-- Added Flex RAM at $C000 to $DFFF using 4 spare RAMB16s
|
-- Added Flex RAM at $C000 to $DFFF using 4 spare RAMB16s
|
-- Added timer and trap logic
|
-- Added timer and trap logic
|
-- Added IDE Interface for Compact Flash
|
-- Added IDE Interface for Compact Flash
|
-- Replaced KBug9s and stack with Sys09Bug.
|
-- Replaced KBug9s and stack with Sys09Bug.
|
--
|
--
|
-- Version 4.0 - 1st February 2008 - John kent
|
-- Version 4.0 - 1st February 2008 - John kent
|
-- Replaced Block RAM with SDRAM Interface
|
-- Replaced Block RAM with SDRAM Interface
|
-- Modified Hold timing for SDRAM
|
-- Modified Hold timing for SDRAM
|
-- Added CF and Ethernet interface
|
-- Added CF and Ethernet interface
|
-- via the 16 bit peripheral bus at $E100
|
-- via the 16 bit peripheral bus at $E100
|
--
|
--
|
--===========================================================================--
|
--===========================================================================--
|
library ieee;
|
library ieee;
|
use ieee.std_logic_1164.all;
|
use ieee.std_logic_1164.all;
|
use IEEE.STD_LOGIC_ARITH.ALL;
|
use IEEE.STD_LOGIC_ARITH.ALL;
|
use IEEE.STD_LOGIC_UNSIGNED.ALL;
|
use IEEE.STD_LOGIC_UNSIGNED.ALL;
|
use ieee.numeric_std.all;
|
use ieee.numeric_std.all;
|
library work;
|
library work;
|
use work.common.all;
|
use work.common.all;
|
use WORK.xsasdram.all;
|
use WORK.xsasdram.all;
|
library unisim;
|
library unisim;
|
use unisim.vcomponents.all;
|
use unisim.vcomponents.all;
|
|
|
entity my_system09 is
|
entity my_system09 is
|
port(
|
port(
|
CLKA : in Std_Logic; -- 100MHz Clock input
|
CLKA : in Std_Logic; -- 100MHz Clock input
|
SW2_N : in Std_logic; -- Master Reset input (active low)
|
SW2_N : in Std_logic; -- Master Reset input (active low)
|
SW3_N : in Std_logic; -- Non Maskable Interrupt input (active low)
|
SW3_N : in Std_logic; -- Non Maskable Interrupt input (active low)
|
|
|
-- PS/2 Keyboard
|
-- PS/2 Keyboard
|
ps2_clk : inout Std_logic;
|
ps2_clk : inout Std_logic;
|
ps2_dat : inout Std_Logic;
|
ps2_dat : inout Std_Logic;
|
|
|
-- CRTC output signals
|
-- CRTC output signals
|
vga_vsync_n : out Std_Logic;
|
vga_vsync_n : out Std_Logic;
|
vga_hsync_n : out Std_Logic;
|
vga_hsync_n : out Std_Logic;
|
vga_blue : out std_logic_vector(2 downto 0);
|
vga_blue : out std_logic_vector(2 downto 0);
|
vga_green : out std_logic_vector(2 downto 0);
|
vga_green : out std_logic_vector(2 downto 0);
|
vga_red : out std_logic_vector(2 downto 0);
|
vga_red : out std_logic_vector(2 downto 0);
|
|
|
-- RS232 Port
|
-- RS232 Port
|
RS232_RXD : in Std_Logic;
|
RS232_RXD : in Std_Logic;
|
RS232_TXD : out Std_Logic;
|
RS232_TXD : out Std_Logic;
|
RS232_CTS : in Std_Logic;
|
RS232_CTS : in Std_Logic;
|
RS232_RTS : out Std_Logic;
|
RS232_RTS : out Std_Logic;
|
|
|
-- Status 7 segment LED
|
-- Status 7 segment LED
|
-- S : out std_logic_vector(7 downto 0);
|
-- S : out std_logic_vector(7 downto 0);
|
|
|
-- SDRAM side
|
-- SDRAM side
|
SDRAM_clkfb : in std_logic; -- feedback SDRAM clock after PCB delays
|
SDRAM_clkfb : in std_logic; -- feedback SDRAM clock after PCB delays
|
SDRAM_clkout : out std_logic; -- clock to SDRAM
|
SDRAM_clkout : out std_logic; -- clock to SDRAM
|
SDRAM_CKE : out std_logic; -- clock-enable to SDRAM
|
SDRAM_CKE : out std_logic; -- clock-enable to SDRAM
|
SDRAM_CS_N : out std_logic; -- chip-select to SDRAM
|
SDRAM_CS_N : out std_logic; -- chip-select to SDRAM
|
SDRAM_RAS_N : out std_logic; -- SDRAM row address strobe
|
SDRAM_RAS_N : out std_logic; -- SDRAM row address strobe
|
SDRAM_CAS_N : out std_logic; -- SDRAM column address strobe
|
SDRAM_CAS_N : out std_logic; -- SDRAM column address strobe
|
SDRAM_WE_N : out std_logic; -- SDRAM write enable
|
SDRAM_WE_N : out std_logic; -- SDRAM write enable
|
SDRAM_BA : out std_logic_vector(1 downto 0); -- SDRAM bank address
|
SDRAM_BA : out std_logic_vector(1 downto 0); -- SDRAM bank address
|
SDRAM_A : out std_logic_vector(12 downto 0); -- SDRAM row/column address
|
SDRAM_A : out std_logic_vector(12 downto 0); -- SDRAM row/column address
|
SDRAM_D : inout std_logic_vector(15 downto 0); -- data from SDRAM
|
SDRAM_D : inout std_logic_vector(15 downto 0); -- data from SDRAM
|
SDRAM_DQMH : out std_logic; -- enable upper-byte of SDRAM databus if true
|
SDRAM_DQMH : out std_logic; -- enable upper-byte of SDRAM databus if true
|
SDRAM_DQML : out std_logic; -- enable lower-byte of SDRAM databus if true
|
SDRAM_DQML : out std_logic; -- enable lower-byte of SDRAM databus if true
|
|
|
-- Peripheral I/O bus $E100 - $E1FF
|
-- Peripheral I/O bus $E100 - $E1FF
|
PB_RD_N : out std_logic;
|
PB_RD_N : out std_logic;
|
PB_WR_N : out std_logic;
|
PB_WR_N : out std_logic;
|
PB_A : out std_logic_vector(4 downto 0);
|
PB_A : out std_logic_vector(4 downto 0);
|
PB_D : inout std_logic_vector(15 downto 0);
|
PB_D : inout std_logic_vector(15 downto 0);
|
|
|
-- IDE Compact Flash $E100 - $E13F
|
-- IDE Compact Flash $E100 - $E13F
|
ide_dmack_n : out std_logic;
|
ide_dmack_n : out std_logic;
|
ide_cs0_n : out std_logic;
|
ide_cs0_n : out std_logic;
|
ide_cs1_n : out std_logic;
|
ide_cs1_n : out std_logic;
|
|
|
-- Ethernet $E140 - $E17F
|
-- 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_aen : out std_logic; -- Ethernet address enable not
|
ether_bhe_n : out std_logic; -- Ethernet bus high enable
|
ether_bhe_n : out std_logic; -- Ethernet bus high enable
|
ether_clk : in std_logic; -- Ethernet clock
|
ether_clk : in std_logic; -- Ethernet clock
|
ether_rdy : in std_logic; -- Ethernet ready
|
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
|
-- Slot 1 $E180 - $E1BF
|
slot1_cs_n : out std_logic;
|
slot1_cs_n : out std_logic;
|
-- slot1_irq : in std_logic;
|
-- slot1_irq : in std_logic;
|
|
|
-- Slot 2 $E1C0 - $E1FF
|
-- Slot 2 $E1C0 - $E1FF
|
slot2_cs_n : out std_logic;
|
slot2_cs_n : out std_logic;
|
-- slot2_irq : in std_logic;
|
-- slot2_irq : in std_logic;
|
|
|
-- Disable Flash
|
-- Disable Flash
|
FLASH_CE_N : out std_logic
|
FLASH_CE_N : out std_logic
|
);
|
);
|
end My_System09;
|
end My_System09;
|
|
|
-------------------------------------------------------------------------------
|
-------------------------------------------------------------------------------
|
-- Architecture for System09
|
-- Architecture for System09
|
-------------------------------------------------------------------------------
|
-------------------------------------------------------------------------------
|
architecture rtl of my_system09 is
|
architecture rtl of my_system09 is
|
|
|
-----------------------------------------------------------------------------
|
-----------------------------------------------------------------------------
|
-- constants
|
-- constants
|
-----------------------------------------------------------------------------
|
-----------------------------------------------------------------------------
|
constant SYS_Clock_Frequency : integer := 50000000; -- FPGA System Clock
|
constant SYS_Clock_Frequency : integer := 50000000; -- FPGA System Clock
|
constant PIX_Clock_Frequency : integer := 25000000; -- VGA Pixel Clock
|
constant PIX_Clock_Frequency : integer := 25000000; -- VGA Pixel Clock
|
constant CPU_Clock_Frequency : integer := 25000000; -- CPU Clock
|
constant CPU_Clock_Frequency : integer := 25000000; -- CPU Clock
|
constant BAUD_Rate : integer := 57600; -- Baud Rate
|
constant BAUD_Rate : integer := 57600; -- Baud Rate
|
constant ACIA_Clock_Frequency : integer := BAUD_Rate * 16;
|
constant ACIA_Clock_Frequency : integer := BAUD_Rate * 16;
|
|
|
type hold_state_type is ( hold_release_state, hold_request_state );
|
type hold_state_type is ( hold_release_state, hold_request_state );
|
|
|
-----------------------------------------------------------------------------
|
-----------------------------------------------------------------------------
|
-- Signals
|
-- Signals
|
-----------------------------------------------------------------------------
|
-----------------------------------------------------------------------------
|
signal rst_n : Std_logic; -- Master Reset input (active low)
|
signal rst_n : Std_logic; -- Master Reset input (active low)
|
signal nmi_n : Std_logic; -- Non Maskable Interrupt input (active low)
|
signal nmi_n : Std_logic; -- Non Maskable Interrupt input (active low)
|
|
|
-- BOOT ROM
|
-- BOOT ROM
|
signal rom_cs : Std_logic;
|
signal rom_cs : Std_logic;
|
signal rom_data_out : Std_Logic_Vector(7 downto 0);
|
signal rom_data_out : Std_Logic_Vector(7 downto 0);
|
|
|
-- Flex Memory & Monitor Stack
|
-- Flex Memory & Monitor Stack
|
signal flex_cs : Std_logic;
|
signal flex_cs : Std_logic;
|
signal flex_data_out : Std_Logic_Vector(7 downto 0);
|
signal flex_data_out : Std_Logic_Vector(7 downto 0);
|
|
|
-- ACIA/UART Interface signals
|
-- ACIA/UART Interface signals
|
signal acia_data_out : Std_Logic_Vector(7 downto 0);
|
signal acia_data_out : Std_Logic_Vector(7 downto 0);
|
signal acia_cs : Std_Logic;
|
signal acia_cs : Std_Logic;
|
signal acia_irq : Std_Logic;
|
signal acia_irq : Std_Logic;
|
signal acia_clk : Std_Logic;
|
signal acia_clk : Std_Logic;
|
signal rxd : Std_Logic;
|
signal rxd : Std_Logic;
|
signal txd : Std_Logic;
|
signal txd : Std_Logic;
|
signal DCD_n : Std_Logic;
|
signal DCD_n : Std_Logic;
|
signal RTS_n : Std_Logic;
|
signal RTS_n : Std_Logic;
|
signal CTS_n : Std_Logic;
|
signal CTS_n : Std_Logic;
|
|
|
-- keyboard port
|
-- keyboard port
|
signal keyboard_data_out : std_logic_vector(7 downto 0);
|
signal keyboard_data_out : std_logic_vector(7 downto 0);
|
signal keyboard_cs : std_logic;
|
signal keyboard_cs : std_logic;
|
signal keyboard_irq : std_logic;
|
signal keyboard_irq : std_logic;
|
|
|
-- RAM
|
-- RAM
|
signal ram_cs : std_logic; -- memory chip select
|
signal ram_cs : std_logic; -- memory chip select
|
signal ram_data_out : std_logic_vector(7 downto 0);
|
signal ram_data_out : std_logic_vector(7 downto 0);
|
signal ram_hold : std_logic; -- hold off slow accesses
|
signal ram_hold : std_logic; -- hold off slow accesses
|
|
|
-- CPU Interface signals
|
-- CPU Interface signals
|
signal cpu_reset : Std_Logic;
|
signal cpu_reset : Std_Logic;
|
signal cpu_clk : Std_Logic;
|
signal cpu_clk : Std_Logic;
|
signal cpu_rw : std_logic;
|
signal cpu_rw : std_logic;
|
signal cpu_vma : std_logic;
|
signal cpu_vma : std_logic;
|
signal cpu_halt : std_logic;
|
signal cpu_halt : std_logic;
|
signal cpu_hold : std_logic;
|
signal cpu_hold : std_logic;
|
signal cpu_firq : std_logic;
|
signal cpu_firq : std_logic;
|
signal cpu_irq : std_logic;
|
signal cpu_irq : std_logic;
|
signal cpu_nmi : std_logic;
|
signal cpu_nmi : std_logic;
|
signal cpu_addr : std_logic_vector(15 downto 0);
|
signal cpu_addr : std_logic_vector(15 downto 0);
|
signal cpu_data_in : std_logic_vector(7 downto 0);
|
signal cpu_data_in : std_logic_vector(7 downto 0);
|
signal cpu_data_out : std_logic_vector(7 downto 0);
|
signal cpu_data_out : std_logic_vector(7 downto 0);
|
|
|
-- Dynamic Address Translation
|
-- Dynamic Address Translation
|
signal dat_cs : std_logic;
|
signal dat_cs : std_logic;
|
signal dat_addr : std_logic_vector(7 downto 0);
|
signal dat_addr : std_logic_vector(7 downto 0);
|
|
|
-- Video Display Unit
|
-- Video Display Unit
|
signal vdu_cs : std_logic;
|
signal vdu_cs : std_logic;
|
signal vdu_data_out : std_logic_vector(7 downto 0);
|
signal vdu_data_out : std_logic_vector(7 downto 0);
|
signal vga_red_o : std_logic;
|
signal vga_red_o : std_logic;
|
signal vga_green_o : std_logic;
|
signal vga_green_o : std_logic;
|
signal vga_blue_o : std_logic;
|
signal vga_blue_o : std_logic;
|
|
|
-- timer
|
-- timer
|
signal timer_data_out : std_logic_vector(7 downto 0);
|
signal timer_data_out : std_logic_vector(7 downto 0);
|
signal timer_cs : std_logic;
|
signal timer_cs : std_logic;
|
signal timer_irq : std_logic;
|
signal timer_irq : std_logic;
|
|
|
-- trap
|
-- trap
|
signal trap_cs : std_logic;
|
signal trap_cs : std_logic;
|
signal trap_data_out : std_logic_vector(7 downto 0);
|
signal trap_data_out : std_logic_vector(7 downto 0);
|
signal trap_irq : std_logic;
|
signal trap_irq : std_logic;
|
|
|
-- Peripheral Bus port
|
-- Peripheral Bus port
|
signal pb_data_out : std_logic_vector(7 downto 0);
|
signal pb_data_out : std_logic_vector(7 downto 0);
|
signal pb_cs : std_logic; -- peripheral bus chip select
|
signal pb_cs : std_logic; -- peripheral bus chip select
|
signal pb_wru : std_logic; -- upper byte write strobe
|
signal pb_wru : std_logic; -- upper byte write strobe
|
signal pb_wrl : std_logic; -- lower byte write strobe
|
signal pb_wrl : std_logic; -- lower byte write strobe
|
signal pb_rdu : std_logic; -- upper byte read strobe
|
signal pb_rdu : std_logic; -- upper byte read strobe
|
signal pb_rdl : std_logic; -- lower byte read strobe
|
signal pb_rdl : std_logic; -- lower byte read strobe
|
signal pb_hold : std_logic; -- hold peripheral bus access
|
signal pb_hold : std_logic; -- hold peripheral bus access
|
signal pb_release : std_logic; -- release hold of peripheral bus
|
signal pb_release : std_logic; -- release hold of peripheral bus
|
signal pb_count : std_logic_vector(3 downto 0); -- hold counter
|
signal pb_count : std_logic_vector(3 downto 0); -- hold counter
|
signal pb_hold_state : hold_state_type;
|
signal pb_hold_state : hold_state_type;
|
signal pb_wreg : std_logic_vector(7 downto 0); -- lower byte write register
|
signal pb_wreg : std_logic_vector(7 downto 0); -- lower byte write register
|
signal pb_rreg : std_logic_vector(7 downto 0); -- lower byte read register
|
signal pb_rreg : std_logic_vector(7 downto 0); -- lower byte read register
|
|
|
-- Peripheral chip selects on Peripheral Bus
|
-- Peripheral chip selects on Peripheral Bus
|
signal ide_cs : std_logic; -- IDE CF interface
|
signal ide_cs : std_logic; -- IDE CF interface
|
signal ether_cs : std_logic; -- Ethernet interface
|
signal ether_cs : std_logic; -- Ethernet interface
|
signal slot1_cs : std_logic; -- Expansion slot 1
|
signal slot1_cs : std_logic; -- Expansion slot 1
|
signal slot2_cs : std_logic; -- Expansion slot 2
|
signal slot2_cs : std_logic; -- Expansion slot 2
|
|
|
|
|
-- SDRAM
|
-- SDRAM
|
|
|
constant FREQ : natural := 100_000; -- operating frequency in KHz
|
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 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 PIPE_EN : boolean := false; -- if true, enable pipelined read operations
|
constant MAX_NOP : natural := 10000; -- number of NOPs before entering self-refresh
|
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 MULTIPLE_ACTIVE_ROWS : boolean := false; -- if true, allow an active row in each bank
|
constant DATA_WIDTH : natural := 16; -- host & SDRAM data width
|
constant DATA_WIDTH : natural := 16; -- host & SDRAM data width
|
constant NROWS : natural := 8192; -- number of rows in SDRAM array
|
constant NROWS : natural := 8192; -- number of rows in SDRAM array
|
constant NCOLS : natural := 512; -- number of columns in SDRAM array
|
constant NCOLS : natural := 512; -- number of columns in SDRAM array
|
constant HADDR_WIDTH : natural := 24; -- host-side address width
|
constant HADDR_WIDTH : natural := 24; -- host-side address width
|
constant SADDR_WIDTH : natural := 13; -- SDRAM-side address width
|
constant SADDR_WIDTH : natural := 13; -- SDRAM-side address width
|
|
|
signal rst_i : std_logic; -- internal reset signal
|
signal rst_i : std_logic; -- internal reset signal
|
signal clk_i : std_logic; -- internal master clock signal
|
signal clk_i : std_logic; -- internal master clock signal
|
signal lock : std_logic; -- SDRAM clock DLL lock indicator
|
signal lock : std_logic; -- SDRAM clock DLL lock indicator
|
|
|
-- signals that go through the SDRAM host-side interface
|
-- signals that go through the SDRAM host-side interface
|
signal opBegun : std_logic; -- SDRAM operation started indicator
|
signal opBegun : std_logic; -- SDRAM operation started indicator
|
signal earlyBegun : std_logic; -- SDRAM operation started indicator
|
signal earlyBegun : std_logic; -- SDRAM operation started indicator
|
signal ramDone : std_logic; -- SDRAM operation complete indicator
|
signal ramDone : std_logic; -- SDRAM operation complete indicator
|
signal rdDone : std_logic; -- SDRAM read operation complete indicator
|
signal rdDone : std_logic; -- SDRAM read operation complete indicator
|
signal wrDone : std_logic; -- SDRAM write 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 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 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 hDOut : std_logic_vector(DATA_WIDTH-1 downto 0); -- host-side data from SDRAM
|
signal hRd : std_logic; -- host-side read control signal
|
signal hRd : std_logic; -- host-side read control signal
|
signal hWr : std_logic; -- host-side write control signal
|
signal hWr : std_logic; -- host-side write control signal
|
signal rdPending : std_logic; -- read operation pending in SDRAM pipeline
|
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_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);
|
type ram_wr_type is (wr_state0, wr_state1, wr_state2, wr_state3, wr_state4);
|
signal ram_rd_state : ram_rd_type;
|
signal ram_rd_state : ram_rd_type;
|
signal ram_wr_state : ram_wr_type;
|
signal ram_wr_state : ram_wr_type;
|
|
|
-- signal BaudCount : std_logic_vector(5 downto 0);
|
-- signal BaudCount : std_logic_vector(5 downto 0);
|
signal CountL : std_logic_vector(23 downto 0);
|
signal CountL : std_logic_vector(23 downto 0);
|
signal clk_count : std_logic_vector(0 downto 0);
|
signal clk_count : std_logic_vector(0 downto 0);
|
signal Clk25 : std_logic;
|
signal Clk25 : std_logic;
|
signal pix_clk : std_logic;
|
signal pix_clk : std_logic;
|
|
|
-----------------------------------------------------------------
|
-----------------------------------------------------------------
|
--
|
--
|
-- CPU09 CPU core
|
-- CPU09 CPU core
|
--
|
--
|
-----------------------------------------------------------------
|
-----------------------------------------------------------------
|
|
|
component cpu09
|
component cpu09
|
port (
|
port (
|
clk: in std_logic;
|
clk: in std_logic;
|
rst: in std_logic;
|
rst: in std_logic;
|
rw: out std_logic; -- Asynchronous memory interface
|
rw: out std_logic; -- Asynchronous memory interface
|
vma: out std_logic;
|
vma: out std_logic;
|
address: out std_logic_vector(15 downto 0);
|
address: out std_logic_vector(15 downto 0);
|
data_in: in std_logic_vector(7 downto 0);
|
data_in: in std_logic_vector(7 downto 0);
|
data_out: out std_logic_vector(7 downto 0);
|
data_out: out std_logic_vector(7 downto 0);
|
halt: in std_logic;
|
halt: in std_logic;
|
hold: in std_logic;
|
hold: in std_logic;
|
irq: in std_logic;
|
irq: in std_logic;
|
nmi: in std_logic;
|
nmi: in std_logic;
|
firq: in std_logic
|
firq: in std_logic
|
);
|
);
|
end component;
|
end component;
|
|
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- 4K Block RAM Monitor ROM
|
-- 4K Block RAM Monitor ROM
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
component mon_rom
|
component mon_rom
|
Port (
|
Port (
|
clk : in std_logic;
|
clk : in std_logic;
|
rst : in std_logic;
|
rst : in std_logic;
|
cs : in std_logic;
|
cs : in std_logic;
|
rw : in std_logic;
|
rw : in std_logic;
|
addr : in std_logic_vector (11 downto 0);
|
addr : in std_logic_vector (11 downto 0);
|
rdata : out std_logic_vector (7 downto 0);
|
rdata : out std_logic_vector (7 downto 0);
|
wdata : in std_logic_vector (7 downto 0)
|
wdata : in std_logic_vector (7 downto 0)
|
);
|
);
|
end component;
|
end component;
|
|
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- 8KBytes Block RAM for FLEX9
|
-- 8KBytes Block RAM for FLEX9
|
-- $C000 - $DFFF
|
-- $C000 - $DFFF
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
component flex_ram
|
component flex_ram
|
Port (
|
Port (
|
clk : in std_logic;
|
clk : in std_logic;
|
rst : in std_logic;
|
rst : in std_logic;
|
cs : in std_logic;
|
cs : in std_logic;
|
rw : in std_logic;
|
rw : in std_logic;
|
addr : in std_logic_vector (12 downto 0);
|
addr : in std_logic_vector (12 downto 0);
|
rdata : out std_logic_vector (7 downto 0);
|
rdata : out std_logic_vector (7 downto 0);
|
wdata : in std_logic_vector (7 downto 0)
|
wdata : in std_logic_vector (7 downto 0)
|
);
|
);
|
end component;
|
end component;
|
|
|
-----------------------------------------------------------------
|
-----------------------------------------------------------------
|
--
|
--
|
-- 6850 Compatible ACIA / UART
|
-- 6850 Compatible ACIA / UART
|
--
|
--
|
-----------------------------------------------------------------
|
-----------------------------------------------------------------
|
|
|
component ACIA_6850
|
component ACIA_6850
|
port (
|
port (
|
clk : in Std_Logic; -- System Clock
|
clk : in Std_Logic; -- System Clock
|
rst : in Std_Logic; -- Reset input (active high)
|
rst : in Std_Logic; -- Reset input (active high)
|
cs : in Std_Logic; -- miniUART Chip Select
|
cs : in Std_Logic; -- miniUART Chip Select
|
rw : in Std_Logic; -- Read / Not Write
|
rw : in Std_Logic; -- Read / Not Write
|
irq : out Std_Logic; -- Interrupt
|
irq : out Std_Logic; -- Interrupt
|
Addr : in Std_Logic; -- Register Select
|
Addr : in Std_Logic; -- Register Select
|
DataIn : in Std_Logic_Vector(7 downto 0); -- Data Bus In
|
DataIn : in Std_Logic_Vector(7 downto 0); -- Data Bus In
|
DataOut : out Std_Logic_Vector(7 downto 0); -- Data Bus Out
|
DataOut : out Std_Logic_Vector(7 downto 0); -- Data Bus Out
|
RxC : in Std_Logic; -- Receive Baud Clock
|
RxC : in Std_Logic; -- Receive Baud Clock
|
TxC : in Std_Logic; -- Transmit Baud Clock
|
TxC : in Std_Logic; -- Transmit Baud Clock
|
RxD : in Std_Logic; -- Receive Data
|
RxD : in Std_Logic; -- Receive Data
|
TxD : out Std_Logic; -- Transmit Data
|
TxD : out Std_Logic; -- Transmit Data
|
DCD_n : in Std_Logic; -- Data Carrier Detect
|
DCD_n : in Std_Logic; -- Data Carrier Detect
|
CTS_n : in Std_Logic; -- Clear To Send
|
CTS_n : in Std_Logic; -- Clear To Send
|
RTS_n : out Std_Logic ); -- Request To send
|
RTS_n : out Std_Logic ); -- Request To send
|
end component;
|
end component;
|
|
|
|
|
-----------------------------------------------------------------
|
-----------------------------------------------------------------
|
--
|
--
|
-- ACIA Clock divider
|
-- ACIA Clock divider
|
--
|
--
|
-----------------------------------------------------------------
|
-----------------------------------------------------------------
|
|
|
component ACIA_Clock
|
component ACIA_Clock
|
generic (
|
generic (
|
SYS_Clock_Frequency : integer := SYS_Clock_Frequency;
|
SYS_Clock_Frequency : integer := SYS_Clock_Frequency;
|
ACIA_Clock_Frequency : integer := ACIA_Clock_Frequency
|
ACIA_Clock_Frequency : integer := ACIA_Clock_Frequency
|
);
|
);
|
port (
|
port (
|
clk : in Std_Logic; -- System Clock Input
|
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;
|
end component;
|
|
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- PS/2 Keyboard
|
-- PS/2 Keyboard
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
|
|
component keyboard
|
component keyboard
|
generic(
|
generic(
|
KBD_Clock_Frequency : integer := CPU_Clock_Frequency
|
KBD_Clock_Frequency : integer := CPU_Clock_Frequency
|
);
|
);
|
port(
|
port(
|
clk : in std_logic;
|
clk : in std_logic;
|
rst : in std_logic;
|
rst : in std_logic;
|
cs : in std_logic;
|
cs : in std_logic;
|
rw : in std_logic;
|
rw : in std_logic;
|
addr : in std_logic;
|
addr : in std_logic;
|
data_in : in std_logic_vector(7 downto 0);
|
data_in : in std_logic_vector(7 downto 0);
|
data_out : out std_logic_vector(7 downto 0);
|
data_out : out std_logic_vector(7 downto 0);
|
irq : out std_logic;
|
irq : out std_logic;
|
kbd_clk : inout std_logic;
|
kbd_clk : inout std_logic;
|
kbd_data : inout std_logic
|
kbd_data : inout std_logic
|
);
|
);
|
end component;
|
end component;
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- Video Display Unit.
|
-- Video Display Unit.
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
component vdu8
|
component vdu8
|
generic(
|
generic(
|
VDU_CLOCK_FREQUENCY : integer := CPU_Clock_Frequency; -- HZ
|
VDU_CLOCK_FREQUENCY : integer := CPU_Clock_Frequency; -- HZ
|
VGA_CLOCK_FREQUENCY : integer := PIX_Clock_Frequency; -- HZ
|
VGA_CLOCK_FREQUENCY : integer := PIX_Clock_Frequency; -- HZ
|
VGA_HOR_CHARS : integer := 80; -- CHARACTERS
|
VGA_HOR_CHARS : integer := 80; -- CHARACTERS
|
VGA_VER_CHARS : integer := 25; -- CHARACTERS
|
VGA_VER_CHARS : integer := 25; -- CHARACTERS
|
VGA_PIXELS_PER_CHAR : integer := 8; -- PIXELS
|
VGA_PIXELS_PER_CHAR : integer := 8; -- PIXELS
|
VGA_LINES_PER_CHAR : integer := 16; -- LINES
|
VGA_LINES_PER_CHAR : integer := 16; -- LINES
|
VGA_HOR_BACK_PORCH : integer := 40; -- PIXELS
|
VGA_HOR_BACK_PORCH : integer := 40; -- PIXELS
|
VGA_HOR_SYNC : integer := 96; -- PIXELS
|
VGA_HOR_SYNC : integer := 96; -- PIXELS
|
VGA_HOR_FRONT_PORCH : integer := 24; -- PIXELS
|
VGA_HOR_FRONT_PORCH : integer := 24; -- PIXELS
|
VGA_VER_BACK_PORCH : integer := 13; -- LINES
|
VGA_VER_BACK_PORCH : integer := 13; -- LINES
|
VGA_VER_SYNC : integer := 1; -- LINES
|
VGA_VER_SYNC : integer := 1; -- LINES
|
VGA_VER_FRONT_PORCH : integer := 36 -- LINES
|
VGA_VER_FRONT_PORCH : integer := 36 -- LINES
|
);
|
);
|
port(
|
port(
|
-- control register interface
|
-- control register interface
|
vdu_clk : in std_logic; -- CPU Clock - 25MHz
|
vdu_clk : in std_logic; -- CPU Clock - 25MHz
|
vdu_rst : in std_logic;
|
vdu_rst : in std_logic;
|
vdu_cs : in std_logic;
|
vdu_cs : in std_logic;
|
vdu_rw : in std_logic;
|
vdu_rw : in std_logic;
|
vdu_addr : in std_logic_vector(2 downto 0);
|
vdu_addr : in std_logic_vector(2 downto 0);
|
vdu_data_in : in std_logic_vector(7 downto 0);
|
vdu_data_in : in std_logic_vector(7 downto 0);
|
vdu_data_out : out std_logic_vector(7 downto 0);
|
vdu_data_out : out std_logic_vector(7 downto 0);
|
|
|
-- vga port connections
|
-- vga port connections
|
vga_clk : in std_logic; -- VGA Pixel Clock - 25 MHz
|
vga_clk : in std_logic; -- VGA Pixel Clock - 25 MHz
|
vga_red_o : out std_logic;
|
vga_red_o : out std_logic;
|
vga_green_o : out std_logic;
|
vga_green_o : out std_logic;
|
vga_blue_o : out std_logic;
|
vga_blue_o : out std_logic;
|
vga_hsync_o : out std_logic;
|
vga_hsync_o : out std_logic;
|
vga_vsync_o : out std_logic
|
vga_vsync_o : out std_logic
|
);
|
);
|
end component;
|
end component;
|
|
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- Timer module
|
-- Timer module
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
|
|
component timer
|
component timer
|
port (
|
port (
|
clk : in std_logic;
|
clk : in std_logic;
|
rst : in std_logic;
|
rst : in std_logic;
|
cs : in std_logic;
|
cs : in std_logic;
|
rw : in std_logic;
|
rw : in std_logic;
|
addr : in std_logic;
|
addr : in std_logic;
|
data_in : in std_logic_vector(7 downto 0);
|
data_in : in std_logic_vector(7 downto 0);
|
data_out : out std_logic_vector(7 downto 0);
|
data_out : out std_logic_vector(7 downto 0);
|
irq : out std_logic
|
irq : out std_logic
|
);
|
);
|
end component;
|
end component;
|
|
|
------------------------------------------------------------
|
------------------------------------------------------------
|
--
|
--
|
-- Bus Trap logic
|
-- Bus Trap logic
|
--
|
--
|
------------------------------------------------------------
|
------------------------------------------------------------
|
|
|
component trap
|
component trap
|
port (
|
port (
|
clk : in std_logic;
|
clk : in std_logic;
|
rst : in std_logic;
|
rst : in std_logic;
|
cs : in std_logic;
|
cs : in std_logic;
|
rw : in std_logic;
|
rw : in std_logic;
|
vma : in std_logic;
|
vma : in std_logic;
|
addr : in std_logic_vector(15 downto 0);
|
addr : in std_logic_vector(15 downto 0);
|
data_in : in std_logic_vector(7 downto 0);
|
data_in : in std_logic_vector(7 downto 0);
|
data_out : out std_logic_vector(7 downto 0);
|
data_out : out std_logic_vector(7 downto 0);
|
irq : out std_logic
|
irq : out std_logic
|
);
|
);
|
end component;
|
end component;
|
|
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- Dynamic Address Translation Registers
|
-- Dynamic Address Translation Registers
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
component dat_ram
|
component dat_ram
|
port (
|
port (
|
clk : in std_logic;
|
clk : in std_logic;
|
rst : in std_logic;
|
rst : in std_logic;
|
cs : in std_logic;
|
cs : in std_logic;
|
rw : in std_logic;
|
rw : in std_logic;
|
addr_lo : in std_logic_vector(3 downto 0);
|
addr_lo : in std_logic_vector(3 downto 0);
|
addr_hi : in std_logic_vector(3 downto 0);
|
addr_hi : in std_logic_vector(3 downto 0);
|
data_in : in std_logic_vector(7 downto 0);
|
data_in : in std_logic_vector(7 downto 0);
|
data_out : out std_logic_vector(7 downto 0)
|
data_out : out std_logic_vector(7 downto 0)
|
);
|
);
|
end component;
|
end component;
|
|
|
component XSASDRAMCntl
|
component XSASDRAMCntl
|
generic(
|
generic(
|
FREQ : natural := FREQ; -- operating frequency in KHz
|
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)
|
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)
|
PIPE_EN : boolean := PIPE_EN; -- if true, enable pipelined read operations
|
PIPE_EN : boolean := PIPE_EN; -- if true, enable pipelined read operations
|
MAX_NOP : natural := MAX_NOP; -- number of NOPs before entering self-refresh
|
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
|
MULTIPLE_ACTIVE_ROWS : boolean := MULTIPLE_ACTIVE_ROWS; -- if true, allow an active row in each bank
|
DATA_WIDTH : natural := DATA_WIDTH; -- host & SDRAM data width
|
DATA_WIDTH : natural := DATA_WIDTH; -- host & SDRAM data width
|
NROWS : natural := NROWS; -- number of rows in SDRAM array
|
NROWS : natural := NROWS; -- number of rows in SDRAM array
|
NCOLS : natural := NCOLS; -- number of columns in SDRAM array
|
NCOLS : natural := NCOLS; -- number of columns in SDRAM array
|
HADDR_WIDTH : natural := HADDR_WIDTH; -- host-side address width
|
HADDR_WIDTH : natural := HADDR_WIDTH; -- host-side address width
|
SADDR_WIDTH : natural := SADDR_WIDTH -- SDRAM-side address width
|
SADDR_WIDTH : natural := SADDR_WIDTH -- SDRAM-side address width
|
);
|
);
|
port(
|
port(
|
-- host side
|
-- host side
|
clk : in std_logic; -- master clock
|
clk : in std_logic; -- master clock
|
bufclk : out std_logic; -- buffered 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)
|
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
|
clk2x : out std_logic; -- double-speed host clock
|
lock : out std_logic; -- true when host clock is locked to master clock
|
lock : out std_logic; -- true when host clock is locked to master clock
|
rst : in std_logic; -- reset
|
rst : in std_logic; -- reset
|
rd : in std_logic; -- initiate read operation
|
rd : in std_logic; -- initiate read operation
|
wr : in std_logic; -- initiate write operation
|
wr : in std_logic; -- initiate write operation
|
earlyOpBegun : out std_logic; -- read/write/self-refresh op begun (async)
|
earlyOpBegun : out std_logic; -- read/write/self-refresh op begun (async)
|
opBegun : out std_logic; -- read/write/self-refresh op begun (clocked)
|
opBegun : out std_logic; -- read/write/self-refresh op begun (clocked)
|
rdPending : out std_logic; -- read operation(s) are still in the pipeline
|
rdPending : out std_logic; -- read operation(s) are still in the pipeline
|
done : out std_logic; -- read or write operation is done
|
done : out std_logic; -- read or write operation is done
|
rdDone : out std_logic; -- read done and data is available
|
rdDone : out std_logic; -- read done and data is available
|
hAddr : in std_logic_vector(HADDR_WIDTH-1 downto 0); -- address from host
|
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
|
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
|
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
|
status : out std_logic_vector(3 downto 0); -- diagnostic status of the FSM
|
|
|
-- SDRAM side
|
-- SDRAM side
|
sclkfb : in std_logic; -- clock from SDRAM after PCB delays
|
sclkfb : in std_logic; -- clock from SDRAM after PCB delays
|
sclk : out std_logic; -- SDRAM clock sync'ed to master clock
|
sclk : out std_logic; -- SDRAM clock sync'ed to master clock
|
cke : out std_logic; -- clock-enable to SDRAM
|
cke : out std_logic; -- clock-enable to SDRAM
|
cs_n : out std_logic; -- chip-select to SDRAM
|
cs_n : out std_logic; -- chip-select to SDRAM
|
ras_n : out std_logic; -- SDRAM row address strobe
|
ras_n : out std_logic; -- SDRAM row address strobe
|
cas_n : out std_logic; -- SDRAM column address strobe
|
cas_n : out std_logic; -- SDRAM column address strobe
|
we_n : out std_logic; -- SDRAM write enable
|
we_n : out std_logic; -- SDRAM write enable
|
ba : out std_logic_vector(1 downto 0); -- SDRAM bank address bits
|
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
|
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
|
sData : inout std_logic_vector(DATA_WIDTH-1 downto 0); -- SDRAM in/out databus
|
dqmh : out std_logic; -- high databits I/O mask
|
dqmh : out std_logic; -- high databits I/O mask
|
dqml : out std_logic -- low databits I/O mask
|
dqml : out std_logic -- low databits I/O mask
|
);
|
);
|
end component;
|
end component;
|
|
|
--
|
--
|
-- Clock buffer
|
-- Clock buffer
|
--
|
--
|
component BUFG
|
component BUFG
|
Port (
|
Port (
|
i: in std_logic;
|
i: in std_logic;
|
o: out std_logic
|
o: out std_logic
|
);
|
);
|
end component;
|
end component;
|
|
|
begin
|
begin
|
-----------------------------------------------------------------------------
|
-----------------------------------------------------------------------------
|
-- Instantiation of internal components
|
-- Instantiation of internal components
|
-----------------------------------------------------------------------------
|
-----------------------------------------------------------------------------
|
|
|
my_cpu : cpu09 port map (
|
my_cpu : cpu09 port map (
|
clk => cpu_clk,
|
clk => cpu_clk,
|
rst => cpu_reset,
|
rst => cpu_reset,
|
rw => cpu_rw,
|
rw => cpu_rw,
|
vma => cpu_vma,
|
vma => cpu_vma,
|
address => cpu_addr(15 downto 0),
|
address => cpu_addr(15 downto 0),
|
data_in => cpu_data_in,
|
data_in => cpu_data_in,
|
data_out => cpu_data_out,
|
data_out => cpu_data_out,
|
halt => cpu_halt,
|
halt => cpu_halt,
|
hold => cpu_hold,
|
hold => cpu_hold,
|
irq => cpu_irq,
|
irq => cpu_irq,
|
nmi => cpu_nmi,
|
nmi => cpu_nmi,
|
firq => cpu_firq
|
firq => cpu_firq
|
);
|
);
|
|
|
my_rom : mon_rom port map (
|
my_rom : mon_rom port map (
|
clk => cpu_clk,
|
clk => cpu_clk,
|
rst => cpu_reset,
|
rst => cpu_reset,
|
cs => rom_cs,
|
cs => rom_cs,
|
rw => '1',
|
rw => '1',
|
addr => cpu_addr(11 downto 0),
|
addr => cpu_addr(11 downto 0),
|
wdata => cpu_data_out,
|
wdata => cpu_data_out,
|
rdata => rom_data_out
|
rdata => rom_data_out
|
);
|
);
|
|
|
my_flex : flex_ram port map (
|
my_flex : flex_ram port map (
|
clk => cpu_clk,
|
clk => cpu_clk,
|
rst => cpu_reset,
|
rst => cpu_reset,
|
cs => flex_cs,
|
cs => flex_cs,
|
rw => cpu_rw,
|
rw => cpu_rw,
|
addr => cpu_addr(12 downto 0),
|
addr => cpu_addr(12 downto 0),
|
rdata => flex_data_out,
|
rdata => flex_data_out,
|
wdata => cpu_data_out
|
wdata => cpu_data_out
|
);
|
);
|
|
|
my_acia : ACIA_6850 port map (
|
my_acia : ACIA_6850 port map (
|
clk => cpu_clk,
|
clk => cpu_clk,
|
rst => cpu_reset,
|
rst => cpu_reset,
|
cs => acia_cs,
|
cs => acia_cs,
|
rw => cpu_rw,
|
rw => cpu_rw,
|
irq => acia_irq,
|
irq => acia_irq,
|
Addr => cpu_addr(0),
|
Addr => cpu_addr(0),
|
Datain => cpu_data_out,
|
Datain => cpu_data_out,
|
DataOut => acia_data_out,
|
DataOut => acia_data_out,
|
RxC => acia_clk,
|
RxC => acia_clk,
|
TxC => acia_clk,
|
TxC => acia_clk,
|
RxD => rxd,
|
RxD => rxd,
|
TxD => txd,
|
TxD => txd,
|
DCD_n => dcd_n,
|
DCD_n => dcd_n,
|
CTS_n => cts_n,
|
CTS_n => cts_n,
|
RTS_n => rts_n
|
RTS_n => rts_n
|
);
|
);
|
|
|
|
|
my_ACIA_Clock : ACIA_Clock
|
my_ACIA_Clock : ACIA_Clock
|
generic map(
|
generic map(
|
SYS_Clock_Frequency => SYS_Clock_Frequency,
|
SYS_Clock_Frequency => SYS_Clock_Frequency,
|
ACIA_Clock_Frequency => ACIA_Clock_Frequency
|
ACIA_Clock_Frequency => ACIA_Clock_Frequency
|
)
|
)
|
port map(
|
port map(
|
clk => Clk_i,
|
clk => Clk_i,
|
acia_clk => acia_clk
|
acia_clk => acia_clk
|
);
|
);
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- PS/2 Keyboard Interface
|
-- PS/2 Keyboard Interface
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
my_keyboard : keyboard
|
my_keyboard : keyboard
|
generic map (
|
generic map (
|
KBD_Clock_Frequency => CPU_Clock_frequency
|
KBD_Clock_Frequency => CPU_Clock_frequency
|
)
|
)
|
port map(
|
port map(
|
clk => cpu_clk,
|
clk => cpu_clk,
|
rst => cpu_reset,
|
rst => cpu_reset,
|
cs => keyboard_cs,
|
cs => keyboard_cs,
|
rw => cpu_rw,
|
rw => cpu_rw,
|
addr => cpu_addr(0),
|
addr => cpu_addr(0),
|
data_in => cpu_data_out(7 downto 0),
|
data_in => cpu_data_out(7 downto 0),
|
data_out => keyboard_data_out(7 downto 0),
|
data_out => keyboard_data_out(7 downto 0),
|
irq => keyboard_irq,
|
irq => keyboard_irq,
|
kbd_clk => ps2_clk,
|
kbd_clk => ps2_clk,
|
kbd_data => ps2_dat
|
kbd_data => ps2_dat
|
);
|
);
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- Video Display Unit instantiation
|
-- Video Display Unit instantiation
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
my_vdu : vdu8
|
my_vdu : vdu8
|
generic map(
|
generic map(
|
VDU_CLOCK_FREQUENCY => CPU_Clock_Frequency, -- HZ
|
VDU_CLOCK_FREQUENCY => CPU_Clock_Frequency, -- HZ
|
VGA_CLOCK_FREQUENCY => PIX_Clock_Frequency, -- HZ
|
VGA_CLOCK_FREQUENCY => PIX_Clock_Frequency, -- HZ
|
VGA_HOR_CHARS => 80, -- CHARACTERS
|
VGA_HOR_CHARS => 80, -- CHARACTERS
|
VGA_VER_CHARS => 25, -- CHARACTERS
|
VGA_VER_CHARS => 25, -- CHARACTERS
|
VGA_PIXELS_PER_CHAR => 8, -- PIXELS
|
VGA_PIXELS_PER_CHAR => 8, -- PIXELS
|
VGA_LINES_PER_CHAR => 16, -- LINES
|
VGA_LINES_PER_CHAR => 16, -- LINES
|
VGA_HOR_BACK_PORCH => 40, -- PIXELS
|
VGA_HOR_BACK_PORCH => 40, -- PIXELS
|
VGA_HOR_SYNC => 96, -- PIXELS
|
VGA_HOR_SYNC => 96, -- PIXELS
|
VGA_HOR_FRONT_PORCH => 24, -- PIXELS
|
VGA_HOR_FRONT_PORCH => 24, -- PIXELS
|
VGA_VER_BACK_PORCH => 13, -- LINES
|
VGA_VER_BACK_PORCH => 13, -- LINES
|
VGA_VER_SYNC => 1, -- LINES
|
VGA_VER_SYNC => 1, -- LINES
|
VGA_VER_FRONT_PORCH => 36 -- LINES
|
VGA_VER_FRONT_PORCH => 36 -- LINES
|
)
|
)
|
port map(
|
port map(
|
|
|
-- Control Registers
|
-- Control Registers
|
vdu_clk => cpu_clk, -- 12.5 MHz System Clock in
|
vdu_clk => cpu_clk, -- 12.5 MHz System Clock in
|
vdu_rst => cpu_reset,
|
vdu_rst => cpu_reset,
|
vdu_cs => vdu_cs,
|
vdu_cs => vdu_cs,
|
vdu_rw => cpu_rw,
|
vdu_rw => cpu_rw,
|
vdu_addr => cpu_addr(2 downto 0),
|
vdu_addr => cpu_addr(2 downto 0),
|
vdu_data_in => cpu_data_out,
|
vdu_data_in => cpu_data_out,
|
vdu_data_out => vdu_data_out,
|
vdu_data_out => vdu_data_out,
|
|
|
-- vga port connections
|
-- vga port connections
|
vga_clk => pix_clk, -- 25 MHz VDU pixel clock
|
vga_clk => pix_clk, -- 25 MHz VDU pixel clock
|
vga_red_o => vga_red_o,
|
vga_red_o => vga_red_o,
|
vga_green_o => vga_green_o,
|
vga_green_o => vga_green_o,
|
vga_blue_o => vga_blue_o,
|
vga_blue_o => vga_blue_o,
|
vga_hsync_o => vga_hsync_n,
|
vga_hsync_o => vga_hsync_n,
|
vga_vsync_o => vga_vsync_n
|
vga_vsync_o => vga_vsync_n
|
);
|
);
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- Timer Module
|
-- Timer Module
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
my_timer : timer port map (
|
my_timer : timer port map (
|
clk => cpu_clk,
|
clk => cpu_clk,
|
rst => cpu_reset,
|
rst => cpu_reset,
|
cs => timer_cs,
|
cs => timer_cs,
|
rw => cpu_rw,
|
rw => cpu_rw,
|
addr => cpu_addr(0),
|
addr => cpu_addr(0),
|
data_in => cpu_data_out,
|
data_in => cpu_data_out,
|
data_out => timer_data_out,
|
data_out => timer_data_out,
|
irq => timer_irq
|
irq => timer_irq
|
);
|
);
|
|
|
----------------------------------------
|
----------------------------------------
|
--
|
--
|
-- Bus Trap Interrupt logic
|
-- Bus Trap Interrupt logic
|
--
|
--
|
----------------------------------------
|
----------------------------------------
|
my_trap : trap port map (
|
my_trap : trap port map (
|
clk => cpu_clk,
|
clk => cpu_clk,
|
rst => cpu_reset,
|
rst => cpu_reset,
|
cs => trap_cs,
|
cs => trap_cs,
|
rw => cpu_rw,
|
rw => cpu_rw,
|
vma => cpu_vma,
|
vma => cpu_vma,
|
addr => cpu_addr,
|
addr => cpu_addr,
|
data_in => cpu_data_out,
|
data_in => cpu_data_out,
|
data_out => trap_data_out,
|
data_out => trap_data_out,
|
irq => trap_irq
|
irq => trap_irq
|
);
|
);
|
|
|
|
|
my_dat : dat_ram port map (
|
my_dat : dat_ram port map (
|
clk => cpu_clk,
|
clk => cpu_clk,
|
rst => cpu_reset,
|
rst => cpu_reset,
|
cs => dat_cs,
|
cs => dat_cs,
|
rw => cpu_rw,
|
rw => cpu_rw,
|
addr_hi => cpu_addr(15 downto 12),
|
addr_hi => cpu_addr(15 downto 12),
|
addr_lo => cpu_addr(3 downto 0),
|
addr_lo => cpu_addr(3 downto 0),
|
data_in => cpu_data_out,
|
data_in => cpu_data_out,
|
data_out => dat_addr(7 downto 0)
|
data_out => dat_addr(7 downto 0)
|
);
|
);
|
|
|
------------------------------------------------------------------------
|
------------------------------------------------------------------------
|
-- Instantiate the SDRAM controller that connects to the memory tester
|
-- Instantiate the SDRAM controller that connects to the memory tester
|
-- module and interfaces to the external SDRAM chip.
|
-- module and interfaces to the external SDRAM chip.
|
------------------------------------------------------------------------
|
------------------------------------------------------------------------
|
u1 : xsaSDRAMCntl
|
u1 : xsaSDRAMCntl
|
generic map(
|
generic map(
|
FREQ => FREQ,
|
FREQ => FREQ,
|
PIPE_EN => PIPE_EN,
|
PIPE_EN => PIPE_EN,
|
DATA_WIDTH => DATA_WIDTH,
|
DATA_WIDTH => DATA_WIDTH,
|
MULTIPLE_ACTIVE_ROWS => MULTIPLE_ACTIVE_ROWS,
|
MULTIPLE_ACTIVE_ROWS => MULTIPLE_ACTIVE_ROWS,
|
NROWS => NROWS,
|
NROWS => NROWS,
|
NCOLS => NCOLS,
|
NCOLS => NCOLS,
|
HADDR_WIDTH => HADDR_WIDTH,
|
HADDR_WIDTH => HADDR_WIDTH,
|
SADDR_WIDTH => SADDR_WIDTH
|
SADDR_WIDTH => SADDR_WIDTH
|
)
|
)
|
port map(
|
port map(
|
-- Host Side
|
-- Host Side
|
clk => CLKA, -- master clock from external clock source (unbuffered)
|
clk => CLKA, -- master clock from external clock source (unbuffered)
|
bufclk => open, -- buffered master clock output
|
bufclk => open, -- buffered master clock output
|
clk1x => clk_i, -- synchronized master clock (accounts for delays to external SDRAM)
|
clk1x => clk_i, -- synchronized master clock (accounts for delays to external SDRAM)
|
clk2x => open, -- synchronized doubled master clock
|
clk2x => open, -- synchronized doubled master clock
|
lock => lock, -- DLL lock indicator
|
lock => lock, -- DLL lock indicator
|
rst => rst_i, -- reset
|
rst => rst_i, -- reset
|
rd => hRd, -- host-side SDRAM read control from memory tester
|
rd => hRd, -- host-side SDRAM read control from memory tester
|
wr => hWr, -- host-side SDRAM write control from memory tester
|
wr => hWr, -- host-side SDRAM write control from memory tester
|
rdPending => rdPending,-- read operation to SDRAM is in progress
|
rdPending => rdPending,-- read operation to SDRAM is in progress
|
opBegun => opBegun, -- indicates memory read/write has begun
|
opBegun => opBegun, -- indicates memory read/write has begun
|
earlyOpBegun => earlyBegun, -- early indicator that memory operation has begun
|
earlyOpBegun => earlyBegun, -- early indicator that memory operation has begun
|
rdDone => rdDone, -- indicates SDRAM memory read operation is done
|
rdDone => rdDone, -- indicates SDRAM memory read operation is done
|
done => ramDone, -- indicates SDRAM memory read or write operation is done
|
done => ramDone, -- indicates SDRAM memory read or write operation is done
|
hAddr => hAddr, -- host-side address from memory tester to SDRAM
|
hAddr => hAddr, -- host-side address from memory tester to SDRAM
|
hDIn => hDIn, -- test data pattern from memory tester to SDRAM
|
hDIn => hDIn, -- test data pattern from memory tester to SDRAM
|
hDOut => hDOut, -- SDRAM data output to memory tester
|
hDOut => hDOut, -- SDRAM data output to memory tester
|
status => open, -- SDRAM controller state (for diagnostics)
|
status => open, -- SDRAM controller state (for diagnostics)
|
-- SDRAM Side
|
-- SDRAM Side
|
sclkfb => SDRAM_clkfb, -- clock feedback with added external PCB delays
|
sclkfb => SDRAM_clkfb, -- clock feedback with added external PCB delays
|
sclk => SDRAM_clkout, -- synchronized clock to external SDRAM
|
sclk => SDRAM_clkout, -- synchronized clock to external SDRAM
|
cke => SDRAM_cke, -- SDRAM clock enable
|
cke => SDRAM_cke, -- SDRAM clock enable
|
cs_n => SDRAM_cs_n, -- SDRAM chip-select
|
cs_n => SDRAM_cs_n, -- SDRAM chip-select
|
ras_n => SDRAM_ras_n, -- SDRAM RAS
|
ras_n => SDRAM_ras_n, -- SDRAM RAS
|
cas_n => SDRAM_cas_n, -- SDRAM CAS
|
cas_n => SDRAM_cas_n, -- SDRAM CAS
|
we_n => SDRAM_we_n, -- SDRAM write-enable
|
we_n => SDRAM_we_n, -- SDRAM write-enable
|
ba => SDRAM_ba, -- SDRAM bank address
|
ba => SDRAM_ba, -- SDRAM bank address
|
sAddr => SDRAM_A, -- SDRAM address
|
sAddr => SDRAM_A, -- SDRAM address
|
sData => SDRAM_D, -- SDRAM databus
|
sData => SDRAM_D, -- SDRAM databus
|
dqmh => SDRAM_dqmh, -- SDRAM DQMH
|
dqmh => SDRAM_dqmh, -- SDRAM DQMH
|
dqml => SDRAM_dqml -- SDRAM DQML
|
dqml => SDRAM_dqml -- SDRAM DQML
|
);
|
);
|
|
|
cpu_clk_buffer : BUFG port map(
|
cpu_clk_buffer : BUFG port map(
|
i => Clk25,
|
i => Clk25,
|
o => cpu_clk
|
o => cpu_clk
|
);
|
);
|
|
|
pix_clk_buffer : BUFG port map(
|
pix_clk_buffer : BUFG port map(
|
i => Clk25,
|
i => Clk25,
|
o => pix_clk
|
o => pix_clk
|
);
|
);
|
|
|
----------------------------------------------------------------------
|
----------------------------------------------------------------------
|
--
|
--
|
-- Process to decode memory map
|
-- Process to decode memory map
|
--
|
--
|
----------------------------------------------------------------------
|
----------------------------------------------------------------------
|
|
|
mem_decode: process( cpu_clk,
|
mem_decode: process( cpu_clk,
|
cpu_addr, cpu_rw, cpu_vma,
|
cpu_addr, cpu_rw, cpu_vma,
|
dat_addr,
|
dat_addr,
|
rom_data_out,
|
rom_data_out,
|
flex_data_out,
|
flex_data_out,
|
acia_data_out,
|
acia_data_out,
|
keyboard_data_out,
|
keyboard_data_out,
|
vdu_data_out,
|
vdu_data_out,
|
pb_data_out,
|
pb_data_out,
|
timer_data_out,
|
timer_data_out,
|
trap_data_out,
|
trap_data_out,
|
ram_data_out
|
ram_data_out
|
)
|
)
|
begin
|
begin
|
cpu_data_in <= (others=>'0');
|
cpu_data_in <= (others=>'0');
|
dat_cs <= '0';
|
dat_cs <= '0';
|
rom_cs <= '0';
|
rom_cs <= '0';
|
flex_cs <= '0';
|
flex_cs <= '0';
|
acia_cs <= '0';
|
acia_cs <= '0';
|
keyboard_cs <= '0';
|
keyboard_cs <= '0';
|
vdu_cs <= '0';
|
vdu_cs <= '0';
|
timer_cs <= '0';
|
timer_cs <= '0';
|
trap_cs <= '0';
|
trap_cs <= '0';
|
pb_cs <= '0';
|
pb_cs <= '0';
|
ide_cs <= '0';
|
ide_cs <= '0';
|
ether_cs <= '0';
|
ether_cs <= '0';
|
slot1_cs <= '0';
|
slot1_cs <= '0';
|
slot2_cs <= '0';
|
slot2_cs <= '0';
|
ram_cs <= '0';
|
ram_cs <= '0';
|
if cpu_addr( 15 downto 8 ) = "11111111" then
|
if cpu_addr( 15 downto 8 ) = "11111111" then
|
cpu_data_in <= rom_data_out;
|
cpu_data_in <= rom_data_out;
|
dat_cs <= cpu_vma; -- write DAT
|
dat_cs <= cpu_vma; -- write DAT
|
rom_cs <= cpu_vma; -- read ROM
|
rom_cs <= cpu_vma; -- read ROM
|
--
|
--
|
-- Sys09Bug Monitor ROM $F000 - $FFFF
|
-- Sys09Bug Monitor ROM $F000 - $FFFF
|
--
|
--
|
elsif dat_addr(3 downto 0) = "1111" then -- $XF000 - $XFFFF
|
elsif dat_addr(3 downto 0) = "1111" then -- $XF000 - $XFFFF
|
cpu_data_in <= rom_data_out;
|
cpu_data_in <= rom_data_out;
|
rom_cs <= cpu_vma;
|
rom_cs <= cpu_vma;
|
|
|
--
|
--
|
-- IO Devices $E000 - $E7FF
|
-- IO Devices $E000 - $E7FF
|
--
|
--
|
elsif dat_addr(3 downto 0) = "1110" then -- $XE000 - $XEFFF
|
elsif dat_addr(3 downto 0) = "1110" then -- $XE000 - $XEFFF
|
case cpu_addr(11 downto 8) is
|
case cpu_addr(11 downto 8) is
|
--
|
--
|
-- SWTPC peripherals from $E000 to $E0FF
|
-- SWTPC peripherals from $E000 to $E0FF
|
--
|
--
|
when "0000" =>
|
when "0000" =>
|
case cpu_addr(7 downto 4) is
|
case cpu_addr(7 downto 4) is
|
--
|
--
|
-- Console Port ACIA $E000 - $E00F
|
-- Console Port ACIA $E000 - $E00F
|
--
|
--
|
when "0000" => -- $E000
|
when "0000" => -- $E000
|
cpu_data_in <= acia_data_out;
|
cpu_data_in <= acia_data_out;
|
acia_cs <= cpu_vma;
|
acia_cs <= cpu_vma;
|
|
|
--
|
--
|
-- Reserved
|
-- Reserved
|
-- Floppy Disk Controller port $E010 - $E01F
|
-- Floppy Disk Controller port $E010 - $E01F
|
--
|
--
|
|
|
--
|
--
|
-- Keyboard port $E020 - $E02F
|
-- Keyboard port $E020 - $E02F
|
--
|
--
|
when "0010" => -- $E020
|
when "0010" => -- $E020
|
cpu_data_in <= keyboard_data_out;
|
cpu_data_in <= keyboard_data_out;
|
keyboard_cs <= cpu_vma;
|
keyboard_cs <= cpu_vma;
|
|
|
--
|
--
|
-- VDU port $E030 - $E03F
|
-- VDU port $E030 - $E03F
|
--
|
--
|
when "0011" => -- $E030
|
when "0011" => -- $E030
|
cpu_data_in <= vdu_data_out;
|
cpu_data_in <= vdu_data_out;
|
vdu_cs <= cpu_vma;
|
vdu_cs <= cpu_vma;
|
|
|
--
|
--
|
-- Reserved SWTPc MP-T Timer $E040 - $E04F
|
-- Reserved SWTPc MP-T Timer $E040 - $E04F
|
--
|
--
|
when "0100" => -- $E040
|
when "0100" => -- $E040
|
cpu_data_in <= (others=> '0');
|
cpu_data_in <= (others=> '0');
|
|
|
--
|
--
|
-- Timer $E050 - $E05F
|
-- Timer $E050 - $E05F
|
--
|
--
|
when "0101" => -- $E050
|
when "0101" => -- $E050
|
cpu_data_in <= timer_data_out;
|
cpu_data_in <= timer_data_out;
|
timer_cs <= cpu_vma;
|
timer_cs <= cpu_vma;
|
|
|
--
|
--
|
-- Bus Trap Logic $E060 - $E06F
|
-- Bus Trap Logic $E060 - $E06F
|
--
|
--
|
when "0110" => -- $E060
|
when "0110" => -- $E060
|
cpu_data_in <= trap_data_out;
|
cpu_data_in <= trap_data_out;
|
trap_cs <= cpu_vma;
|
trap_cs <= cpu_vma;
|
|
|
--
|
--
|
-- Reserved SWTPc MP-ID PIA Timer/Printer Port $E080 - $E08F
|
-- Reserved SWTPc MP-ID PIA Timer/Printer Port $E080 - $E08F
|
--
|
--
|
|
|
--
|
--
|
-- Reserved SWTPc MP-ID PTM 6840 Timer Port $E090 - $E09F
|
-- Reserved SWTPc MP-ID PTM 6840 Timer Port $E090 - $E09F
|
--
|
--
|
|
|
--
|
--
|
-- Remaining 6 slots reserved for non SWTPc Peripherals
|
-- Remaining 6 slots reserved for non SWTPc Peripherals
|
--
|
--
|
when others => -- $E0A0 to $E0FF
|
when others => -- $E0A0 to $E0FF
|
null;
|
null;
|
end case;
|
end case;
|
--
|
--
|
-- XST-3.0 Peripheral Bus goes here
|
-- XST-3.0 Peripheral Bus goes here
|
-- $E100 to $E1FF
|
-- $E100 to $E1FF
|
-- Four devices
|
-- Four devices
|
-- IDE, Ethernet, Slot1, Slot2
|
-- IDE, Ethernet, Slot1, Slot2
|
--
|
--
|
when "0001" =>
|
when "0001" =>
|
cpu_data_in <= pb_data_out;
|
cpu_data_in <= pb_data_out;
|
pb_cs <= cpu_vma;
|
pb_cs <= cpu_vma;
|
case cpu_addr(7 downto 6) is
|
case cpu_addr(7 downto 6) is
|
--
|
--
|
-- IDE Interface $E100 to $E13F
|
-- IDE Interface $E100 to $E13F
|
--
|
--
|
when "00" =>
|
when "00" =>
|
ide_cs <= cpu_vma;
|
ide_cs <= cpu_vma;
|
--
|
--
|
-- Ethernet Interface $E140 to $E17F
|
-- Ethernet Interface $E140 to $E17F
|
--
|
--
|
when "01" =>
|
when "01" =>
|
ether_cs <= cpu_vma;
|
ether_cs <= cpu_vma;
|
--
|
--
|
-- Slot 1 Interface $E180 to $E1BF
|
-- Slot 1 Interface $E180 to $E1BF
|
--
|
--
|
when "10" =>
|
when "10" =>
|
slot1_cs <= cpu_vma;
|
slot1_cs <= cpu_vma;
|
--
|
--
|
-- Slot 2 Interface $E1C0 to $E1FF
|
-- Slot 2 Interface $E1C0 to $E1FF
|
--
|
--
|
when "11" =>
|
when "11" =>
|
slot2_cs <= cpu_vma;
|
slot2_cs <= cpu_vma;
|
--
|
--
|
-- Nothing else
|
-- Nothing else
|
--
|
--
|
when others =>
|
when others =>
|
null;
|
null;
|
end case;
|
end case;
|
--
|
--
|
-- $E200 to $EFFF reserved for future use
|
-- $E200 to $EFFF reserved for future use
|
--
|
--
|
when others =>
|
when others =>
|
null;
|
null;
|
end case;
|
end case;
|
--
|
--
|
-- Flex RAM $0C000 - $0DFFF
|
-- Flex RAM $0C000 - $0DFFF
|
--
|
--
|
elsif dat_addr(7 downto 1) = "0000110" then -- $0C000 - $0DFFF
|
elsif dat_addr(7 downto 1) = "0000110" then -- $0C000 - $0DFFF
|
cpu_data_in <= flex_data_out;
|
cpu_data_in <= flex_data_out;
|
flex_cs <= cpu_vma;
|
flex_cs <= cpu_vma;
|
--
|
--
|
-- Everything else is RAM
|
-- Everything else is RAM
|
--
|
--
|
else
|
else
|
cpu_data_in <= ram_data_out;
|
cpu_data_in <= ram_data_out;
|
ram_cs <= cpu_vma;
|
ram_cs <= cpu_vma;
|
end if;
|
end if;
|
end process;
|
end process;
|
|
|
|
|
--
|
--
|
-- 16-bit Peripheral Bus
|
-- 16-bit Peripheral Bus
|
-- 6809 Big endian
|
-- 6809 Big endian
|
-- ISA bus little endian
|
-- ISA bus little endian
|
-- Not sure about IDE interface
|
-- 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 )
|
begin
|
begin
|
pb_wru <= pb_cs and (not cpu_rw) and (not cpu_addr(0));
|
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) ;
|
pb_wrl <= pb_cs and (not cpu_rw) and cpu_addr(0) ;
|
pb_rdu <= pb_cs and cpu_rw and (not cpu_addr(0));
|
pb_rdu <= pb_cs and cpu_rw and (not cpu_addr(0));
|
pb_rdl <= pb_cs and cpu_rw and cpu_addr(0) ;
|
pb_rdl <= pb_cs and cpu_rw and cpu_addr(0) ;
|
pb_a <= cpu_addr(5 downto 1);
|
pb_a <= cpu_addr(5 downto 1);
|
|
|
--
|
--
|
-- Register upper byte from CPU on first CPU write
|
-- Register upper byte from CPU on first CPU write
|
-- and lower byte from the peripheral bus on first CPU read
|
-- and lower byte from the peripheral bus on first CPU read
|
--
|
--
|
if cpu_reset = '1' then
|
if cpu_reset = '1' then
|
pb_wreg <= (others => '0');
|
pb_wreg <= (others => '0');
|
pb_rreg <= (others => '0');
|
pb_rreg <= (others => '0');
|
elsif clk_i'event and clk_i ='1' then
|
elsif clk_i'event and clk_i ='1' then
|
if pb_wru = '1' then
|
if pb_wru = '1' then
|
pb_wreg <= cpu_data_out;
|
pb_wreg <= cpu_data_out;
|
end if;
|
end if;
|
if pb_rdu = '1' then
|
if pb_rdu = '1' then
|
pb_rreg <= pb_d(7 downto 0);
|
pb_rreg <= pb_d(7 downto 0);
|
end if;
|
end if;
|
end if;
|
end if;
|
--
|
--
|
-- Peripheral bus read and write strobes are
|
-- Peripheral bus read and write strobes are
|
-- Syncronized with the 50 MHz clock
|
-- Syncronized with the 50 MHz clock
|
-- and are asserted until the peripheral bus hold is released
|
-- and are asserted until the peripheral bus hold is released
|
--
|
--
|
if cpu_reset = '1' then
|
if cpu_reset = '1' then
|
pb_wr_n <= '1';
|
pb_wr_n <= '1';
|
pb_rd_n <= '1';
|
pb_rd_n <= '1';
|
elsif clk_i'event and clk_i ='1' then
|
elsif clk_i'event and clk_i ='1' then
|
if pb_hold = '1' then
|
if pb_hold = '1' then
|
pb_wr_n <= not pb_wrl;
|
pb_wr_n <= not pb_wrl;
|
pb_rd_n <= not pb_rdu;
|
pb_rd_n <= not pb_rdu;
|
else
|
else
|
pb_wr_n <= '1';
|
pb_wr_n <= '1';
|
pb_rd_n <= '1';
|
pb_rd_n <= '1';
|
end if;
|
end if;
|
end if;
|
end if;
|
--
|
--
|
-- The peripheral bus will be an output
|
-- The peripheral bus will be an output
|
-- the registered even byte on data(15 downto 8)
|
-- the registered even byte on data(15 downto 8)
|
-- and the CPU odd bytes on data(7 downto 0)
|
-- and the CPU odd bytes on data(7 downto 0)
|
-- on odd byte writes
|
-- on odd byte writes
|
--
|
--
|
if pb_wrl = '1' then
|
if pb_wrl = '1' then
|
pb_d <= pb_wreg & cpu_data_out;
|
pb_d <= pb_wreg & cpu_data_out;
|
else
|
else
|
pb_d <= (others => 'Z');
|
pb_d <= (others => 'Z');
|
end if;
|
end if;
|
|
|
--
|
--
|
-- On even byte reads,
|
-- On even byte reads,
|
-- the CPU reads the low (even) byte of the peripheral bus
|
-- the CPU reads the low (even) byte of the peripheral bus
|
-- On odd byte reads,
|
-- On odd byte reads,
|
-- the CPU reads the registered (odd byte) input from the peripheral bus
|
-- the CPU reads the registered (odd byte) input from the peripheral bus
|
--
|
--
|
if pb_rdu = '1' then
|
if pb_rdu = '1' then
|
pb_data_out <= pb_d(15 downto 8);
|
pb_data_out <= pb_d(15 downto 8);
|
elsif pb_rdl = '1' then
|
elsif pb_rdl = '1' then
|
pb_data_out <= pb_rreg;
|
pb_data_out <= pb_rreg;
|
else
|
else
|
pb_data_out <= (others => '0');
|
pb_data_out <= (others => '0');
|
end if;
|
end if;
|
|
|
end process;
|
end process;
|
|
|
--
|
--
|
-- Hold Peripheral bus accesses for a few cycles
|
-- 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
|
begin
|
if cpu_reset = '1' then
|
if cpu_reset = '1' then
|
pb_release <= '0';
|
pb_release <= '0';
|
pb_count <= "0000";
|
pb_count <= "0000";
|
pb_hold_state <= hold_release_state;
|
pb_hold_state <= hold_release_state;
|
elsif cpu_clk'event and cpu_clk='1' then
|
elsif cpu_clk'event and cpu_clk='1' then
|
--
|
--
|
-- The perpheral bus hold signal should be generated on
|
-- The perpheral bus hold signal should be generated on
|
-- 16 bit bus read which will be on even byte reads or
|
-- 16 bit bus read which will be on even byte reads or
|
-- 16 bit bus write which will be on odd byte writes.
|
-- 16 bit bus write which will be on odd byte writes.
|
--
|
--
|
case pb_hold_state is
|
case pb_hold_state is
|
when hold_release_state =>
|
when hold_release_state =>
|
pb_release <= '0';
|
pb_release <= '0';
|
if (pb_rdu = '1') or (pb_wrl = '1') then
|
if (pb_rdu = '1') or (pb_wrl = '1') then
|
pb_count <= "0100";
|
pb_count <= "0100";
|
pb_hold_state <= hold_request_state;
|
pb_hold_state <= hold_request_state;
|
elsif (pb_rdl = '1') or (pb_wru = '1') then
|
elsif (pb_rdl = '1') or (pb_wru = '1') then
|
pb_release <= '1';
|
pb_release <= '1';
|
pb_hold_state <= hold_release_state;
|
pb_hold_state <= hold_release_state;
|
end if;
|
end if;
|
|
|
when hold_request_state =>
|
when hold_request_state =>
|
if pb_count = "0000" then
|
if pb_count = "0000" then
|
if ether_rdy = '1' then
|
if ether_rdy = '1' then
|
pb_release <= '1';
|
pb_release <= '1';
|
pb_hold_state <= hold_release_state;
|
pb_hold_state <= hold_release_state;
|
end if;
|
end if;
|
else
|
else
|
pb_count <= pb_count - "0001";
|
pb_count <= pb_count - "0001";
|
end if;
|
end if;
|
when others =>
|
when others =>
|
null;
|
null;
|
end case;
|
end case;
|
end if;
|
end if;
|
end process;
|
end process;
|
|
|
--
|
--
|
-- Compact Flash Control
|
-- Compact Flash Control
|
--
|
--
|
compact_flash: process( ide_cs, cpu_addr )
|
compact_flash: process( ide_cs, cpu_addr )
|
begin
|
begin
|
ide_cs0_n <= not( ide_cs ) or cpu_addr(4);
|
ide_cs0_n <= not( ide_cs ) or cpu_addr(4);
|
ide_cs1_n <= not( ide_cs and cpu_addr(4));
|
ide_cs1_n <= not( ide_cs and cpu_addr(4));
|
ide_dmack_n <= '1';
|
ide_dmack_n <= '1';
|
end process;
|
end process;
|
|
|
--
|
--
|
-- Interrupts and other bus control signals
|
-- Interrupts and other bus control signals
|
--
|
--
|
interrupts : process( lock, rst_n, nmi_n,
|
interrupts : process( lock, rst_n, nmi_n,
|
pb_cs, pb_hold, pb_release,
|
pb_cs, pb_hold, pb_release,
|
ram_cs, ram_hold,
|
ram_cs, ram_hold,
|
ether_irq,
|
ether_irq,
|
acia_irq,
|
acia_irq,
|
keyboard_irq,
|
keyboard_irq,
|
trap_irq,
|
trap_irq,
|
timer_irq
|
timer_irq
|
)
|
)
|
begin
|
begin
|
cpu_reset <= (not rst_n) or (not lock); -- CPU reset is active high
|
cpu_reset <= (not rst_n) or (not lock); -- CPU reset is active high
|
pb_hold <= pb_cs and (not pb_release);
|
pb_hold <= pb_cs and (not pb_release);
|
cpu_irq <= acia_irq or keyboard_irq;
|
cpu_irq <= acia_irq or keyboard_irq;
|
cpu_nmi <= trap_irq or not( nmi_n );
|
cpu_nmi <= trap_irq or not( nmi_n );
|
cpu_firq <= timer_irq;
|
cpu_firq <= timer_irq;
|
cpu_halt <= '0';
|
cpu_halt <= '0';
|
cpu_hold <= pb_hold or ram_hold;
|
cpu_hold <= pb_hold or ram_hold;
|
end process;
|
end process;
|
|
|
|
|
--
|
--
|
-- Flash 7 segment LEDS
|
-- Flash 7 segment LEDS
|
--
|
--
|
my_led_flasher: process( Clk_i, rst_n, CountL )
|
my_led_flasher: process( Clk_i, rst_n, CountL )
|
begin
|
begin
|
if rst_n = '0' then
|
if rst_n = '0' then
|
CountL <= "000000000000000000000000";
|
CountL <= "000000000000000000000000";
|
elsif(Clk_i'event and Clk_i = '1') then
|
elsif(Clk_i'event and Clk_i = '1') then
|
CountL <= CountL + 1;
|
CountL <= CountL + 1;
|
end if;
|
end if;
|
-- S(7 downto 0) <= CountL(23 downto 16);
|
-- S(7 downto 0) <= CountL(23 downto 16);
|
end process;
|
end process;
|
|
|
--
|
--
|
-- Generate a 25 MHz Clock from 50 MHz
|
-- Generate a 25 MHz Clock from 50 MHz
|
--
|
--
|
my_prescaler : process( Clk_i, clk_count )
|
my_prescaler : process( Clk_i, clk_count )
|
begin
|
begin
|
if Clk_i'event and Clk_i = '1' then
|
if Clk_i'event and Clk_i = '1' then
|
clk_count(0) <= not clk_count(0);
|
clk_count(0) <= not clk_count(0);
|
end if;
|
end if;
|
Clk25 <= clk_count(0);
|
Clk25 <= clk_count(0);
|
end process;
|
end process;
|
|
|
--
|
--
|
-- Push buttons
|
-- Push buttons
|
--
|
--
|
my_switch_assignments : process( SW2_N, SW3_N, rst_n )
|
my_switch_assignments : process( SW2_N, SW3_N, rst_n )
|
begin
|
begin
|
rst_n <= SW2_N;
|
rst_n <= SW2_N;
|
rst_i <= not rst_n;
|
rst_i <= not rst_n;
|
nmi_n <= SW3_N;
|
nmi_n <= SW3_N;
|
--
|
--
|
-- Disable Flash memory
|
-- Disable Flash memory
|
--
|
--
|
FLASH_CE_N <= '1';
|
FLASH_CE_N <= '1';
|
end process;
|
end process;
|
|
|
--
|
--
|
-- RS232 signals:
|
-- RS232 signals:
|
--
|
--
|
my_acia_assignments : process( RS232_RXD, RS232_CTS, txd, rts_n )
|
my_acia_assignments : process( RS232_RXD, RS232_CTS, txd, rts_n )
|
begin
|
begin
|
rxd <= RS232_RXD;
|
rxd <= RS232_RXD;
|
cts_n <= RS232_CTS;
|
cts_n <= RS232_CTS;
|
dcd_n <= '0';
|
dcd_n <= '0';
|
RS232_TXD <= txd;
|
RS232_TXD <= txd;
|
RS232_RTS <= rts_n;
|
RS232_RTS <= rts_n;
|
end process;
|
end process;
|
|
|
--
|
--
|
-- Pin assignments for ethernet controller
|
-- Pin assignments for ethernet controller
|
--
|
--
|
my_ethernet_assignments : process( clk_i, cpu_reset, ether_cs )
|
my_ethernet_assignments : process( clk_i, cpu_reset, ether_cs )
|
begin
|
begin
|
ether_cs_n <= not ether_cs;
|
ether_cs_n <= not ether_cs;
|
ether_aen <= not ether_cs; -- Ethernet address enable not
|
ether_aen <= not ether_cs; -- Ethernet address enable not
|
ether_bhe_n <= '1'; -- Ethernet bus high enable - 8 bit access only
|
ether_bhe_n <= '1'; -- Ethernet bus high enable - 8 bit access only
|
end process;
|
end process;
|
|
|
--
|
--
|
-- I/O expansion slot assignments
|
-- I/O expansion slot assignments
|
--
|
--
|
my_slot_assignments : process( slot1_cs, slot2_cs)
|
my_slot_assignments : process( slot1_cs, slot2_cs)
|
begin
|
begin
|
slot1_cs_n <= not slot1_cs;
|
slot1_cs_n <= not slot1_cs;
|
slot2_cs_n <= not slot2_cs;
|
slot2_cs_n <= not slot2_cs;
|
end process;
|
end process;
|
|
|
--
|
--
|
-- VGA ouputs
|
-- VGA ouputs
|
--
|
--
|
my_vga_assignments : process( vga_red_o, vga_green_o, vga_blue_o )
|
my_vga_assignments : process( vga_red_o, vga_green_o, vga_blue_o )
|
begin
|
begin
|
VGA_red(0) <= vga_red_o;
|
VGA_red(0) <= vga_red_o;
|
VGA_red(1) <= vga_red_o;
|
VGA_red(1) <= vga_red_o;
|
VGA_red(2) <= vga_red_o;
|
VGA_red(2) <= vga_red_o;
|
VGA_green(0) <= vga_green_o;
|
VGA_green(0) <= vga_green_o;
|
VGA_green(1) <= vga_green_o;
|
VGA_green(1) <= vga_green_o;
|
VGA_green(2) <= vga_green_o;
|
VGA_green(2) <= vga_green_o;
|
VGA_blue(0) <= vga_blue_o;
|
VGA_blue(0) <= vga_blue_o;
|
VGA_blue(1) <= vga_blue_o;
|
VGA_blue(1) <= vga_blue_o;
|
VGA_blue(2) <= vga_blue_o;
|
VGA_blue(2) <= vga_blue_o;
|
end process;
|
end process;
|
|
|
--
|
--
|
-- SDRAM assignments
|
-- SDRAM assignments
|
--
|
--
|
my_sdram_assignments : process( cpu_clk, clk_i, cpu_reset,
|
my_sdram_assignments : process( cpu_clk, clk_i, cpu_reset,
|
opBegun, rdDone, wrDone,
|
opBegun, rdDone, wrDone,
|
ram_rd_state, ram_wr_state,
|
ram_rd_state, ram_wr_state,
|
cpu_addr, dat_addr,
|
cpu_addr, dat_addr,
|
cpu_data_out, hDout,
|
cpu_data_out, hDout,
|
ram_cs, cpu_rw, ram_hold )
|
ram_cs, cpu_rw, ram_hold )
|
begin
|
begin
|
if( cpu_reset = '1' ) then
|
if( cpu_reset = '1' ) then
|
hWr <= '0';
|
hWr <= '0';
|
hRd <= '0';
|
hRd <= '0';
|
wrDone <= '0';
|
wrDone <= '0';
|
ram_wr_state <= wr_state0;
|
ram_wr_state <= wr_state0;
|
ram_rd_state <= rd_state0;
|
ram_rd_state <= rd_state0;
|
|
|
elsif( clk_i'event and clk_i='0' ) then
|
elsif( clk_i'event and clk_i='0' ) then
|
--
|
--
|
-- read state machine
|
-- read state machine
|
--
|
--
|
case ram_rd_state is
|
case ram_rd_state is
|
|
|
when rd_state0 =>
|
when rd_state0 =>
|
if (ram_hold = '1') and (cpu_rw = '1') then
|
if (ram_hold = '1') and (cpu_rw = '1') then
|
hRd <= '1';
|
hRd <= '1';
|
ram_rd_state <= rd_state1;
|
ram_rd_state <= rd_state1;
|
end if;
|
end if;
|
|
|
when rd_state1 =>
|
when rd_state1 =>
|
if opBegun = '1' then
|
if opBegun = '1' then
|
ram_rd_state <= rd_state2;
|
ram_rd_state <= rd_state2;
|
end if;
|
end if;
|
|
|
when rd_state2 =>
|
when rd_state2 =>
|
if rdDone = '1' then
|
if rdDone = '1' then
|
hRd <= '0';
|
hRd <= '0';
|
ram_rd_state <= rd_state3;
|
ram_rd_state <= rd_state3;
|
end if;
|
end if;
|
|
|
when rd_state3 =>
|
when rd_state3 =>
|
if rdDone = '0' then
|
if rdDone = '0' then
|
ram_rd_state <= rd_state0;
|
ram_rd_state <= rd_state0;
|
end if;
|
end if;
|
|
|
when others =>
|
when others =>
|
hRd <= '0';
|
hRd <= '0';
|
ram_rd_state <= rd_state0;
|
ram_rd_state <= rd_state0;
|
end case;
|
end case;
|
|
|
--
|
--
|
-- Write state machine
|
-- Write state machine
|
--
|
--
|
case ram_wr_state is
|
case ram_wr_state is
|
|
|
when wr_state0 =>
|
when wr_state0 =>
|
if (ram_hold = '1') and (cpu_rw = '0') then
|
if (ram_hold = '1') and (cpu_rw = '0') then
|
hWr <= '1';
|
hWr <= '1';
|
wrDone <= '0';
|
wrDone <= '0';
|
ram_wr_state <= wr_state1;
|
ram_wr_state <= wr_state1;
|
end if;
|
end if;
|
|
|
when wr_state1 =>
|
when wr_state1 =>
|
if opBegun = '1' then
|
if opBegun = '1' then
|
hWr <= '0';
|
hWr <= '0';
|
wrDone <= '0';
|
wrDone <= '0';
|
ram_wr_state <= wr_state2;
|
ram_wr_state <= wr_state2;
|
end if;
|
end if;
|
|
|
when wr_state2 =>
|
when wr_state2 =>
|
hWr <= '0';
|
hWr <= '0';
|
wrDone <= '0';
|
wrDone <= '0';
|
ram_wr_state <= wr_state3;
|
ram_wr_state <= wr_state3;
|
|
|
when wr_state3 =>
|
when wr_state3 =>
|
hWr <= '0';
|
hWr <= '0';
|
wrDone <= '1';
|
wrDone <= '1';
|
ram_wr_state <= wr_state4;
|
ram_wr_state <= wr_state4;
|
|
|
when wr_state4 =>
|
when wr_state4 =>
|
hWr <= '0';
|
hWr <= '0';
|
wrDone <= '0';
|
wrDone <= '0';
|
ram_wr_state <= wr_state0;
|
ram_wr_state <= wr_state0;
|
|
|
when others =>
|
when others =>
|
hWr <= '0';
|
hWr <= '0';
|
wrDone <= '0';
|
wrDone <= '0';
|
ram_wr_state <= wr_state0;
|
ram_wr_state <= wr_state0;
|
|
|
end case;
|
end case;
|
|
|
end if;
|
end if;
|
--
|
--
|
-- Strobe host RD and WR signals high on RAM select
|
-- Strobe host RD and WR signals high on RAM select
|
-- Return low when cycle has started
|
-- Return low when cycle has started
|
--
|
--
|
if( cpu_reset = '1' ) then
|
if( cpu_reset = '1' ) then
|
ram_hold <= '0';
|
ram_hold <= '0';
|
elsif( cpu_clk'event and cpu_clk='1' ) then
|
elsif( cpu_clk'event and cpu_clk='1' ) then
|
--
|
--
|
-- Hold is intitiated when the RAM is selected
|
-- Hold is intitiated when the RAM is selected
|
-- and released when access cycle is complete
|
-- and released when access cycle is complete
|
--
|
--
|
if (ram_hold = '0') and (ram_cs = '1') then
|
if (ram_hold = '0') and (ram_cs = '1') then
|
ram_hold <= '1';
|
ram_hold <= '1';
|
elsif (ram_hold = '1') and ((rdDone = '1') or (wrDone = '1')) then
|
elsif (ram_hold = '1') and ((rdDone = '1') or (wrDone = '1')) then
|
ram_hold <= '0';
|
ram_hold <= '0';
|
end if;
|
end if;
|
end if;
|
end if;
|
|
|
hAddr(23 downto 20) <= "0000";
|
hAddr(23 downto 20) <= "0000";
|
hAddr(19 downto 12) <= dat_addr;
|
hAddr(19 downto 12) <= dat_addr;
|
hAddr(11 downto 0) <= cpu_addr(11 downto 0);
|
hAddr(11 downto 0) <= cpu_addr(11 downto 0);
|
hDin(7 downto 0) <= cpu_data_out;
|
hDin(7 downto 0) <= cpu_data_out;
|
hDin(15 downto 8) <= (others => '0');
|
hDin(15 downto 8) <= (others => '0');
|
ram_data_out <= hDout(7 downto 0);
|
ram_data_out <= hDout(7 downto 0);
|
|
|
end process;
|
end process;
|
|
|
end rtl; --===================== End of architecture =======================--
|
end rtl; --===================== End of architecture =======================--
|
|
|
|
|
