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[/] [System09/] [rev_86/] [rtl/] [VHDL/] [keyboard.vhd] - Blame information for rev 159

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Line No. Rev Author Line
1 19 dilbert57
---------------------------------------------------------------------------------------
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--
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-- Author: John Kent
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-- Date  : April 2, 2004
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-- Interface to John Clayton's PS2 keyboard
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--
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---------------------------------------------------------------------------------------
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--
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-- 7th Februaury 2007 - John Kent
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-- Added Generics for Keyboard Timing
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--
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library ieee;
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   use ieee.std_logic_1164.all;
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   use IEEE.STD_LOGIC_ARITH.ALL;
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   use IEEE.STD_LOGIC_UNSIGNED.ALL;
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   use ieee.numeric_std.all;
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entity keyboard is
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  generic (
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  KBD_Clock_Frequency : integer
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  );
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  port(
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  clk             : in    std_logic;
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  rst             : in    std_logic;
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  cs              : in    std_logic;
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  rw              : in    std_logic;
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  addr            : in    std_logic;
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  data_in         : in    std_logic_vector(7 downto 0);
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  data_out        : out   std_logic_vector(7 downto 0);
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  irq             : out   std_logic;
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  kbd_clk         : inout std_logic;
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  kbd_data        : inout std_logic
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  );
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end keyboard;
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architecture rtl of keyboard is
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constant Clock_Frequency_MHz : integer := KBD_Clock_Frequency / 1000000;
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signal kbd_stat       : std_logic_vector(7 downto 0);
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signal kbd_ctrl       : std_logic_vector(7 downto 6);
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signal kbd_ascii_code : std_logic_vector(7 downto 0);
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signal kbd_tx_data    : std_logic_vector(7 downto 0);
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signal kbd_read       : std_logic;
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signal kbd_write      : std_logic;
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signal kbd_write_ack  : std_logic;
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component ps2_keyboard_interface
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  generic (
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  Frequency_MHz    : integer := Clock_Frequency_MHz
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  );
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  port(
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  clk             : in    std_logic;
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  reset           : in    std_logic;
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  ps2_clk         : inout std_logic;
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  ps2_data        : inout std_logic;
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  rx_extended     : out   std_logic;
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  rx_released     : out   std_logic;
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  rx_shift_key_on : out   std_logic;
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--  rx_scan_code    : out   std_logic_vector(7 downto 0);
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  rx_ascii        : out   std_logic_vector(7 downto 0);
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  rx_data_ready   : out   std_logic;       -- rx_read_o
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  rx_read         : in    std_logic;       -- rx_read_ack_i
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  tx_data         : in    std_logic_vector(7 downto 0);
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  tx_write        : in    std_logic;
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  tx_write_ack    : out   std_logic;
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  tx_error_no_keyboard_ack      : out  std_logic
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  );
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end component;
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begin
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my_ps2_keyboard_interface : ps2_keyboard_interface
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  generic map (
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  Frequency_MHz   => Clock_Frequency_MHz
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  )
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  port map(
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  clk             => clk,
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  reset           => rst,
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  ps2_clk         => kbd_clk,
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  ps2_data        => kbd_data,
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  rx_extended     => kbd_stat(2),
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  rx_released     => kbd_stat(3),
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  rx_shift_key_on => kbd_stat(4),
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  rx_ascii        => kbd_ascii_code,
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  rx_data_ready   => kbd_stat(0),
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  rx_read         => kbd_read,
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  tx_data         => kbd_tx_data,
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  tx_write        => kbd_write,
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  tx_write_ack    => kbd_write_ack,
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  tx_error_no_keyboard_ack      => kbd_stat(5)
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  );
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keyboard_strobe : process( clk, rst, cs, rw, kbd_stat  )
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begin
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        if( rst = '1' ) then
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                kbd_read <= '0';
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        elsif( clk'event and clk='0' ) then
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                if( cs='1' and rw='1' and addr='1' ) then
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                        kbd_read <= '1';
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                elsif( kbd_stat(0)='1' ) then
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                        kbd_read <= '0';
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                else
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                        kbd_read <= kbd_read;
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                end if;
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        end if;
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end process;
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--
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-- read keyboard registers
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--
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keyboard_read : process( addr, kbd_ascii_code, kbd_stat )
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begin
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        if( addr = '1' ) then
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                data_out <= kbd_ascii_code;
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        else
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                data_out <= kbd_stat;
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   end if;
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end process;
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--
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-- Write to keyboard register
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--
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keyboard_write : process( clk, rst, cs, rw, addr, data_in, kbd_tx_data,
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                                                                         kbd_write, kbd_write_ack )
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begin
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        if(rst = '1' ) then
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           kbd_ctrl   <= "00";
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           kbd_tx_data <= "00000000";
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                kbd_write  <= '0';
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        elsif( clk'event and clk='0' ) then
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                if( cs='1' and rw='0' ) then
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                        if( addr='1' ) then
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                                kbd_tx_data  <= data_in;
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                                kbd_ctrl    <= kbd_ctrl;
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                                kbd_write   <= '1';
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                        else
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                                kbd_tx_data  <= kbd_tx_data;
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                                kbd_ctrl    <= data_in(7 downto 6);
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                                kbd_write   <= kbd_write;
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                        end if;
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                elsif( kbd_write_ack='1' ) then
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                        kbd_write <= '0';
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                else
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                        kbd_write <= kbd_write;
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                end if;
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                kbd_stat(1) <= not kbd_write;
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        end if;
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end process;
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keyboard_interrupt : process( kbd_ctrl, kbd_stat )
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begin
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        kbd_stat(6)     <= kbd_ctrl(6);
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        kbd_stat(7) <= kbd_ctrl(7) and kbd_stat(0);
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        irq         <= kbd_stat(7);
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end process;
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end rtl;
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