repo2/chameleon2/chameleon2_io_ps2iec.vhd
| 872 | markw | -- -----------------------------------------------------------------------
|
|
--
|
|||
-- Turbo Chameleon 64
|
|||
--
|
|||
-- Multi purpose FPGA expansion for the Commodore 64 computer
|
|||
--
|
|||
-- -----------------------------------------------------------------------
|
|||
-- Copyright 2005-2018 by Peter Wendrich (pwsoft@syntiac.com)
|
|||
-- http://www.syntiac.com
|
|||
--
|
|||
-- This source file is free software: you can redistribute it and/or modify
|
|||
-- it under the terms of the GNU Lesser General Public License as published
|
|||
-- by the Free Software Foundation, either version 3 of the License, or
|
|||
-- (at your option) any later version.
|
|||
--
|
|||
-- This source file is distributed in the hope that it will be useful,
|
|||
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|||
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|||
-- GNU General Public License for more details.
|
|||
--
|
|||
-- You should have received a copy of the GNU General Public License
|
|||
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|||
--
|
|||
-- -----------------------------------------------------------------------
|
|||
-- I/O controller entity for the PS2IEC multiplexer.
|
|||
-- This provides capturing and reading the state of the (multiplexed)
|
|||
-- PS/2 and IEC lines.
|
|||
--
|
|||
-- -----------------------------------------------------------------------
|
|||
-- clk - System clock
|
|||
-- ps2iec_sel - Select line, connect on toplevel to port with same name
|
|||
-- ps2iec - Multiplexed signals, connect on toplevel to port with same name
|
|||
--
|
|||
-- ps2_mouse_clk - State of the PS/2 mouse clock signal
|
|||
-- ps2_mouse_dat - State of the PS/2 mouse data signal
|
|||
-- ps2_mouse_clk - State of the PS/2 keyboard clock signal
|
|||
-- ps2_mouse_dat - State of the PS/2 keyboard data signal
|
|||
--
|
|||
-- iec_clk - State of the CLK line on the IEC bus
|
|||
-- iec_srq - State of the SRQ line on the IEC bus
|
|||
-- iec_atn - State of the ATN line on the IEC bus
|
|||
-- iec_dat - State of the DAT line on the IEC bus
|
|||
-- -----------------------------------------------------------------------
|
|||
library ieee;
|
|||
use ieee.std_logic_1164.all;
|
|||
use ieee.numeric_std.all;
|
|||
-- -----------------------------------------------------------------------
|
|||
entity chameleon2_io_ps2iec is
|
|||
port (
|
|||
clk : in std_logic;
|
|||
-- Mux signals
|
|||
ps2iec_sel : out std_logic;
|
|||
ps2iec : in unsigned(3 downto 0);
|
|||
-- Decoded
|
|||
ps2_mouse_clk : out std_logic;
|
|||
ps2_mouse_dat : out std_logic;
|
|||
ps2_keyboard_clk : out std_logic;
|
|||
ps2_keyboard_dat : out std_logic;
|
|||
iec_clk : out std_logic;
|
|||
iec_srq : out std_logic;
|
|||
iec_atn : out std_logic;
|
|||
iec_dat : out std_logic
|
|||
);
|
|||
end entity;
|
|||
architecture rtl of chameleon2_io_ps2iec is
|
|||
signal state_reg : unsigned(2 downto 0) := "000";
|
|||
signal ps2iec_reg : unsigned(3 downto 0) := "1111";
|
|||
signal ps2_mouse_clk_reg : std_logic := '1';
|
|||
signal ps2_mouse_dat_reg : std_logic := '1';
|
|||
signal ps2_keyboard_clk_reg : std_logic := '1';
|
|||
signal ps2_keyboard_dat_reg : std_logic := '1';
|
|||
signal iec_clk_reg : std_logic := '1';
|
|||
signal iec_srq_reg : std_logic := '1';
|
|||
signal iec_atn_reg : std_logic := '1';
|
|||
signal iec_dat_reg : std_logic := '1';
|
|||
begin
|
|||
ps2iec_sel <= state_reg(2);
|
|||
ps2_mouse_clk <= ps2_mouse_clk_reg;
|
|||
ps2_mouse_dat <= ps2_mouse_dat_reg;
|
|||
ps2_keyboard_clk <= ps2_keyboard_clk_reg;
|
|||
ps2_keyboard_dat <= ps2_keyboard_dat_reg;
|
|||
iec_clk <= iec_clk_reg;
|
|||
iec_srq <= iec_srq_reg;
|
|||
iec_atn <= iec_atn_reg;
|
|||
iec_dat <= iec_dat_reg;
|
|||
process(clk)
|
|||
begin
|
|||
if rising_edge(clk) then
|
|||
state_reg <= state_reg + 1;
|
|||
ps2iec_reg <= ps2iec;
|
|||
if state_reg = "011" then
|
|||
-- Capture PS2 lines
|
|||
ps2_mouse_dat_reg <= ps2iec_reg(0);
|
|||
ps2_mouse_clk_reg <= ps2iec_reg(1);
|
|||
ps2_keyboard_clk_reg <= ps2iec_reg(2);
|
|||
ps2_keyboard_dat_reg <= ps2iec_reg(3);
|
|||
end if;
|
|||
if state_reg = "111" then
|
|||
-- Capture IEC lines
|
|||
iec_atn_reg <= ps2iec_reg(0);
|
|||
iec_dat_reg <= ps2iec_reg(1);
|
|||
iec_clk_reg <= ps2iec_reg(2);
|
|||
iec_srq_reg <= ps2iec_reg(3);
|
|||
end if;
|
|||
end if;
|
|||
end process;
|
|||
end architecture;
|