Revision 126
Added by markw about 11 years ago
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-- Multi purpose FPGA expansion for the Commodore 64 computer
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--
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-- -----------------------------------------------------------------------
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-- Copyright 2005-2011 by Peter Wendrich (pwsoft@syntiac.com)
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-- Copyright 2005-2012 by Peter Wendrich (pwsoft@syntiac.com)
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-- All Rights Reserved.
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--
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-- Allowed to be used in your own projects that are targeted for the
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-- Turbo Chameleon 64 cartridge.
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--
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-- http://www.syntiac.com/chameleon.html
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-- -----------------------------------------------------------------------
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--
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-- Chameleon docking station
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--
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-- -----------------------------------------------------------------------
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-- clk - system clock
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-- enable - must be cycle high to advance statemachine (sync with MUX)
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-- ena_1mhz - must be one cycle high each micro-second. Used for timers.
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-- clk - system clock
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-- docking_station - must be high when docking-station is available.
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-- This can be determined by the state of the phi2 pin.
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-- dotclock_n - Connect to the dotclock_n pin.
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-- io_ef_n - Connect to the io_ef_n pin.
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-- rom_hl_n - Connect to the rom_hl_n pin.
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-- irq_q - IRQ pin output (open drain output, 0 is drive low, 1 is input)
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-- joystick* - Joystick outputs (fire2, fire1, right, left, down, up) low active
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-- keys - State of the keyboard (low is pressed)
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-- restore_key_n - State of the restore key (low is pressed)
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--
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-- amiga_power_led - Control input for the POWER LED on the Amiga keyboard.
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-- amiga_drive_led - Control input for the DRIVE LED on the Amiga keyboard.
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-- amiga_reset_n - Low when the Amiga keyboard does a reset.
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-- amiga_trigger - One clock high when the Amiga keyboard has send a new scancode.
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-- amiga_scancode - Value of the last received scancode from the Amiga keyboard.
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-- -----------------------------------------------------------------------
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library IEEE;
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entity chameleon_docking_station is
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port (
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clk : in std_logic;
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enable : in std_logic;
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ena_1mhz : in std_logic;
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docking_station : in std_logic;
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dotclock_n : in std_logic;
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io_ef_n : in std_logic;
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rom_lh_n : in std_logic;
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irq_d : in std_logic;
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irq_q : out std_logic;
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joystick1 : out unsigned(5 downto 0);
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| ... | ... | |
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architecture rtl of chameleon_docking_station is
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constant shift_reg_bits : integer := 13*8;
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-- We put the out-of-sync detection just before the actual sync-pulse.
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-- Gives it the biggest chance of catching a sync-problem.
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constant out_of_sync_pos : integer := 102;
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signal shift_reg : unsigned(shift_reg_bits-1 downto 0);
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signal bit_cnt : unsigned(7 downto 0) := (others => '0');
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signal once : std_logic := '0';
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shift_reg <= (not rom_lh_n_reg) & shift_reg(shift_reg'high downto 1);
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bit_cnt <= bit_cnt + 1;
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end if;
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if (io_ef_n_reg = '1') and (bit_cnt = out_of_sync_pos) then
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-- Out of sync detection.
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-- Wait for the MCU on the docking-station to release io_ef
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-- Then we can continue and syncronise on the next io_ef pulse that comes.
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bit_cnt <= to_unsigned(out_of_sync_pos, bit_cnt'length);
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end if;
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if (io_ef_n_reg = '1') and (bit_cnt >= shift_reg_bits) then
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-- Word trigger. Signals start of serial bit-stream.
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bit_cnt <= (others => '0');
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Switched to using Peters chameleon_io module. Great, gives c64 joystick and cdtv support!