fpga64_keyboard_matrix_mark_mcdougall.vhd

FPGA64的VHDL源代码

-- -----------------------------------------------------------------------
--
--                                 FPGA 64
--
--     A fully functional commodore 64 implementation in a single FPGA
--
-- -----------------------------------------------------------------------
-- Copyright 2005-2008 by Peter Wendrich ([e-mail])
-- http://www.syntiac.com/fpga64.html
-- -----------------------------------------------------------------------
-- 'Joystick emulation on keypad' additions by
-- Mark McDougall ([e-mail])
-- -----------------------------------------------------------------------
--
-- VIC20/C64 Keyboard matrix
--
-- Hardware huh?
--	In original machine if a key is pressed a contact is made.
--	Bidirectional reading is possible on real hardware, which is difficult
--	to emulate. (set backwardsReadingEnabled to '1' if you want this enabled).
--	Then we have the joysticks, one of which is normally connected
--	to a OUTPUT pin.
--
-- Emulation:
--	All pins are high except when one is driven low and there is a
--	connection. This is consistent with joysticks that force a line
--	low too. CIA will put '1's when set to input to help this emulation.
--
-- -----------------------------------------------------------------------

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.std_logic_unsigned.ALL;
use IEEE.numeric_std.ALL;

entity fpga64_keyboard_matrix is
	port (
		clk: in std_logic;
		theScanCode: in unsigned(7 downto 0);
		newScanCode: in std_logic;

		joyA: in unsigned(4 downto 0);
		joyB: in unsigned(4 downto 0);

		pai: in unsigned(7 downto 0);
		pbi: in unsigned(7 downto 0);
		pao: out unsigned(7 downto 0);
		pbo: out unsigned(7 downto 0);
		
		videoKey : out std_logic;
		traceKey : out std_logic;
		trace2Key : out std_logic;

		-- Config
		-- backwardsReadingEnabled = 1 allows reversal of PIA registers to still work.
		-- not needed for kernel/normal operation only for some specific programs.
		-- set to 0 to save some hardware.
		backwardsReadingEnabled : in std_logic
	);
end fpga64_keyboard_matrix;

architecture rtl of fpga64_keyboard_matrix is	
	signal extendedFlag: std_logic := '0';
	signal releaseFlag: std_logic := '0';

	signal key_del: std_logic := '0';
	signal key_return: std_logic := '0';
	signal key_left: std_logic := '0';
	signal key_right: std_logic := '0';
	signal key_f7: std_logic := '0';
	signal key_f1: std_logic := '0';
	signal key_f3: std_logic := '0';
	signal key_f5: std_logic := '0';
	signal key_up: std_logic := '0';
	signal key_down: std_logic := '0';

	signal key_3: std_logic := '0';
	signal key_W: std_logic := '0';
	signal key_A: std_logic := '0';
	signal key_4: std_logic := '0';
	signal key_Z: std_logic := '0';
	signal key_S: std_logic := '0';
	signal key_E: std_logic := '0';
	signal key_shiftl: std_logic := '0';

	signal key_5: std_logic := '0';
	signal key_R: std_logic := '0';
	signal key_D: std_logic := '0';
	signal key_6: std_logic := '0';
	signal key_C: std_logic := '0';
	signal key_F: std_logic := '0';
	signal key_T: std_logic := '0';
	signal key_X: std_logic := '0';
	
	signal key_7: std_logic := '0';
	signal key_Y: std_logic := '0';
	signal key_G: std_logic := '0';
	signal key_8: std_logic := '0';
	signal key_B: std_logic := '0';
	signal key_H: std_logic := '0';
	signal key_U: std_logic := '0';
	signal key_V: std_logic := '0';

	signal key_9: std_logic := '0';
	signal key_I: std_logic := '0';
	signal key_J: std_logic := '0';
	signal key_0: std_logic := '0';
	signal key_M: std_logic := '0';
	signal key_K: std_logic := '0';
	signal key_O: std_logic := '0';
	signal key_N: std_logic := '0';

	signal key_plus: std_logic := '0';
	signal key_P: std_logic := '0';
	signal key_L: std_logic := '0';
	signal key_minus: std_logic := '0';
	signal key_dot: std_logic := '0';
	signal key_colon: std_logic := '0';
	signal key_at: std_logic := '0';
	signal key_comma: std_logic := '0';

	signal key_pound: std_logic := '0';
	signal key_star: std_logic := '0';
	signal key_semicolon: std_logic := '0';
	signal key_home: std_logic := '0';
	signal key_shiftr: std_logic := '0';
	signal key_equal: std_logic := '0';
	signal key_arrowup: std_logic := '0';
	signal key_slash: std_logic := '0';

	signal key_1: std_logic := '0';
	signal key_arrowleft: std_logic := '0';
	signal key_ctrl: std_logic := '0';
	signal key_2: std_logic := '0';
	signal key_space: std_logic := '0';
	signal key_commodore: std_logic := '0';
	signal key_Q: std_logic := '0';
	signal key_runstop: std_logic := '0';

	-- for joystick emulation on PS2
	signal joySelKey : std_logic;
	signal joyKeys : std_logic_vector(joyA'range);	-- active high
	signal joyA_s : unsigned(joyA'range);						-- active low
	signal joyB_s : unsigned(joyB'range);						-- active low
	signal joySel : std_logic_vector(1 downto 0) := "00";
	
begin

	--
	-- cycle though joystick emulation options on <F11>	
	--
	-- "00" - PORTA = JOYA or JOYKEYS, PORTB = JOYB
	-- "01" - PORTA = JOYA, PORTB = JOYB or JOYKEYS
	-- "10" - PORTA = JOYA, PORTB = JOYKEYS
	-- "11" - PORTA = JOYKEYS, PORTB = JOYA
	
	process (clk) --, reset)
	begin
		if rising_edge(clk) then
			if joySelKey = '1' then
				joySel <= joySel + 1;
			end if;
		end if;
	end process;

	joyA_s <= joyA and not unsigned(joyKeys) when joySel = "00" else
						not unsigned(joyKeys) when joySel = "11" else
						joyA;
	joyB_s <= joyB when joySel = "00" else
						joyB and not unsigned(joyKeys) when joySel = "01" else
						not unsigned(joyKeys) when joySel = "10" else
						joyA;

	matrix: process(clk)
	begin
		--if reset = '1' then
		--	joySelKey <= '0';
		--	joyKeys <= (others => '0');
		if rising_edge(clk) then
			-- reading A, scan pattern on B
			pao(0) <= pai(0) and joyA_s(0) and
				((not backwardsReadingEnabled) or
				((pbi(0) or not key_del) and
				(pbi(1) or not key_return) and
				(pbi(2) or not (key_left or key_right)) and
				(pbi(3) or not key_f7) and
				(pbi(4) or not key_f1) and
				(pbi(5) or not key_f3) and
				(pbi(6) or not key_f5) and
				(pbi(7) or not (key_up or key_down))));
			pao(1) <= pai(1) and joyA_s(1) and
				((not backwardsReadingEnabled) or
				((pbi(0) or not key_3) and
				(pbi(1) or not key_W) and
				(pbi(2) or not key_A) and
				(pbi(3) or not key_4) and
				(pbi(4) or not key_Z) and
				(pbi(5) or not key_S) and
				(pbi(6) or not key_E) and
				(pbi(7) or not (key_left or key_up or key_shiftL))));
			pao(2) <= pai(2) and joyA_s(2) and
				((not backwardsReadingEnabled) or
				((pbi(0) or not key_5) and
				(pbi(1) or not key_R) and
				(pbi(2) or not key_D) and
				(pbi(3) or not key_6) and
				(pbi(4) or not key_C) and
				(pbi(5) or not key_F) and
				(pbi(6) or not key_T) and
				(pbi(7) or not key_X)));
			pao(3) <= pai(3) and joyA_s(3) and
				((not backwardsReadingEnabled) or
				((pbi(0) or not key_7) and
				(pbi(1) or not key_Y) and
				(pbi(2) or not key_G) and
				(pbi(3) or not key_8) and
				(pbi(4) or not key_B) and
				(pbi(5) or not key_H) and
				(pbi(6) or not key_U) and
				(pbi(7) or not key_V)));
			pao(4) <= pai(4) and joyA_s(4) and