|
-- -----------------------------------------------------------------------
|
|
--
|
|
-- Turbo Chameleon
|
|
--
|
|
-- Multi purpose FPGA expansion for the Commodore 64 computer
|
|
--
|
|
-- -----------------------------------------------------------------------
|
|
-- Copyright 2005-2012 by Peter Wendrich (pwsoft@syntiac.com)
|
|
-- All Rights Reserved.
|
|
--
|
|
-- Allowed to be used in your own projects that are targeted for the
|
|
-- Turbo Chameleon 64 cartridge.
|
|
--
|
|
-- http://www.syntiac.com/chameleon.html
|
|
-- -----------------------------------------------------------------------
|
|
--
|
|
-- Chameleon docking station
|
|
--
|
|
-- -----------------------------------------------------------------------
|
|
-- clk - system clock
|
|
-- docking_station - must be high when docking-station is available.
|
|
-- This can be determined by the state of the phi2 pin.
|
|
-- dotclock_n - Connect to the dotclock_n pin.
|
|
-- io_ef_n - Connect to the io_ef_n pin.
|
|
-- rom_hl_n - Connect to the rom_hl_n pin.
|
|
-- irq_q - IRQ pin output (open drain output, 0 is drive low, 1 is input)
|
|
-- joystick* - Joystick outputs (fire2, fire1, right, left, down, up) low active
|
|
-- keys - State of the keyboard (low is pressed)
|
|
-- restore_key_n - State of the restore key (low is pressed)
|
|
--
|
|
-- amiga_power_led - Control input for the POWER LED on the Amiga keyboard.
|
|
-- amiga_drive_led - Control input for the DRIVE LED on the Amiga keyboard.
|
|
-- amiga_reset_n - Low when the Amiga keyboard does a reset.
|
|
-- amiga_trigger - One clock high when the Amiga keyboard has send a new scancode.
|
|
-- amiga_scancode - Value of the last received scancode from the Amiga keyboard.
|
|
-- -----------------------------------------------------------------------
|
|
|
|
library IEEE;
|
|
use IEEE.STD_LOGIC_1164.ALL;
|
|
use IEEE.numeric_std.all;
|
|
|
|
-- -----------------------------------------------------------------------
|
|
|
|
entity chameleon_docking_station is
|
|
port (
|
|
clk : in std_logic;
|
|
docking_station : in std_logic;
|
|
|
|
dotclock_n : in std_logic;
|
|
io_ef_n : in std_logic;
|
|
rom_lh_n : in std_logic;
|
|
irq_q : out std_logic;
|
|
|
|
joystick1 : out unsigned(5 downto 0);
|
|
joystick2 : out unsigned(5 downto 0);
|
|
joystick3 : out unsigned(5 downto 0);
|
|
joystick4 : out unsigned(5 downto 0);
|
|
-- 0 = col0, row0
|
|
-- 1 = col1, row0
|
|
-- 8 = col0, row1
|
|
-- 63 = col7, row7
|
|
keys : out unsigned(63 downto 0);
|
|
restore_key_n : out std_logic;
|
|
|
|
-- Amiga keyboard
|
|
amiga_power_led : in std_logic;
|
|
amiga_drive_led : in std_logic;
|
|
amiga_reset_n : out std_logic;
|
|
amiga_trigger : out std_logic;
|
|
amiga_scancode : out unsigned(7 downto 0)
|
|
);
|
|
end entity;
|
|
|
|
-- -----------------------------------------------------------------------
|
|
|
|
architecture rtl of chameleon_docking_station is
|
|
constant shift_reg_bits : integer := 13*8;
|
|
-- We put the out-of-sync detection just before the actual sync-pulse.
|
|
-- Gives it the biggest chance of catching a sync-problem.
|
|
constant out_of_sync_pos : integer := 102;
|
|
signal shift_reg : unsigned(shift_reg_bits-1 downto 0);
|
|
signal bit_cnt : unsigned(7 downto 0) := (others => '0');
|
|
signal once : std_logic := '0';
|
|
|
|
signal key_reg : unsigned(63 downto 0) := (others => '1');
|
|
signal restore_n_reg : std_logic := '1';
|
|
signal joystick1_reg : unsigned(5 downto 0) := (others => '0');
|
|
signal joystick2_reg : unsigned(5 downto 0) := (others => '0');
|
|
signal joystick3_reg : unsigned(5 downto 0) := (others => '0');
|
|
signal joystick4_reg : unsigned(5 downto 0) := (others => '0');
|
|
signal dotclock_n_reg : std_logic := '0';
|
|
signal dotclock_n_dly : std_logic := '0';
|
|
signal io_ef_n_reg : std_logic := '0';
|
|
signal rom_lh_n_reg : std_logic := '1';
|
|
signal irq_q_reg : std_logic := '1';
|
|
|
|
signal amiga_reset_n_reg : std_logic := '0';
|
|
signal amiga_trigger_reg : std_logic := '0';
|
|
signal amiga_scancode_reg : unsigned(7 downto 0) := (others => '0');
|
|
|
|
signal last_keys_reg : unsigned(63 downto 0) := (others => '1');
|
|
signal approved_keys_reg : unsigned(63 downto 0) := (others => '1');
|
|
begin
|
|
joystick1 <= joystick1_reg;
|
|
joystick2 <= joystick2_reg;
|
|
joystick3 <= joystick3_reg;
|
|
joystick4 <= joystick4_reg;
|
|
keys <= approved_keys_reg;
|
|
restore_key_n <= restore_n_reg;
|
|
amiga_reset_n <= amiga_reset_n_reg;
|
|
amiga_trigger <= amiga_trigger_reg;
|
|
amiga_scancode <= amiga_scancode_reg;
|
|
irq_q <= irq_q_reg;
|
|
|
|
--
|
|
-- Sample DotClock, IO_EF and ROM_LH input.
|
|
process(clk) is
|
|
begin
|
|
if rising_edge(clk) then
|
|
dotclock_n_reg <= dotclock_n;
|
|
dotclock_n_dly <= dotclock_n_reg;
|
|
io_ef_n_reg <= io_ef_n;
|
|
rom_lh_n_reg <= rom_lh_n;
|
|
end if;
|
|
end process;
|
|
|
|
--
|
|
-- Receive serial stream
|
|
process(clk) is
|
|
begin
|
|
if rising_edge(clk) then
|
|
if (dotclock_n_reg = '0') and (dotclock_n_dly = '1') then
|
|
shift_reg <= (not rom_lh_n_reg) & shift_reg(shift_reg'high downto 1);
|
|
bit_cnt <= bit_cnt + 1;
|
|
end if;
|
|
if (io_ef_n_reg = '1') and (bit_cnt = out_of_sync_pos) then
|
|
-- Out of sync detection.
|
|
-- Wait for the MCU on the docking-station to release io_ef
|
|
-- Then we can continue and syncronise on the next io_ef pulse that comes.
|
|
bit_cnt <= to_unsigned(out_of_sync_pos, bit_cnt'length);
|
|
end if;
|
|
if (io_ef_n_reg = '1') and (bit_cnt >= shift_reg_bits) then
|
|
-- Word trigger. Signals start of serial bit-stream.
|
|
bit_cnt <= (others => '0');
|
|
end if;
|
|
end if;
|
|
end process;
|
|
|
|
--
|
|
-- Amiga keyboard LED control
|
|
process(clk) is
|
|
begin
|
|
if rising_edge(clk) then
|
|
irq_q_reg <= '1';
|
|
if (bit_cnt >= 40) and (bit_cnt < 56) then
|
|
irq_q_reg <= amiga_power_led;
|
|
end if;
|
|
if (bit_cnt >= 72) and (bit_cnt < 88) then
|
|
irq_q_reg <= amiga_drive_led;
|
|
end if;
|
|
end if;
|
|
end process;
|
|
|
|
--
|
|
-- Decode bytes
|
|
process(clk) is
|
|
begin
|
|
if rising_edge(clk) then
|
|
if bit_cnt = shift_reg_bits then
|
|
-- Map shifted bits to joysticks
|
|
last_keys_reg <= key_reg;
|
|
|
|
if ((shift_reg(101 downto 96) and shift_reg(85 downto 80) and joystick1_reg and joystick2_reg) = "11111" and last_keys_reg = key_reg) then
|
|
approved_keys_reg <= key_reg;
|
|
end if;
|
|
|
|
joystick1_reg <= shift_reg(101 downto 96);
|
|
joystick2_reg <= shift_reg(85 downto 80);
|
|
joystick3_reg <= shift_reg(102)& shift_reg(103) & shift_reg(92) & shift_reg(93) & shift_reg(94) & shift_reg(95);
|
|
joystick4_reg <= shift_reg(86) & shift_reg(87) & shift_reg(88) & shift_reg(89) & shift_reg(90) & shift_reg(91);
|
|
restore_n_reg <= shift_reg(1);
|
|
|
|
-- Map shifted bits to C64 keyboard
|
|
if (shift_reg(87 downto 80) = X"FF") and (shift_reg(103 downto 96) = X"FF") then
|
|
for row in 0 to 7 loop
|
|
for col in 0 to 7 loop
|
|
-- uC scans column wise.
|
|
key_reg(row*8 + col) <= shift_reg(16 + col*8 + row);
|
|
end loop;
|
|
end loop;
|
|
else
|
|
-- Prevent conflict between keyboard and joystick.
|
|
-- Relase all keyboard keys while joystick button(s) are pressed.
|
|
key_reg <= (others => '1');
|
|
end if;
|
|
|
|
-- Amiga keyboard
|
|
amiga_reset_n_reg <= shift_reg(2);
|
|
if shift_reg(0) = '1' then
|
|
amiga_scancode_reg <= shift_reg(15 downto 8);
|
|
amiga_trigger_reg <= once;
|
|
end if;
|
|
once <= '0';
|
|
end if;
|
|
if (io_ef_n_reg = '1') then
|
|
once <= '1';
|
|
end if;
|
|
|
|
-- No docking station connected.
|
|
-- Disable all outputs to prevent conflicts.
|
|
if docking_station = '0' then
|
|
joystick1_reg <= (others => '1');
|
|
joystick2_reg <= (others => '1');
|
|
joystick3_reg <= (others => '1');
|
|
joystick4_reg <= (others => '1');
|
|
key_reg <= (others => '1');
|
|
restore_n_reg <= '1';
|
|
amiga_reset_n_reg <= '1';
|
|
end if;
|
|
end if;
|
|
end process;
|
|
end architecture;
|