AtomBusMon/src/Z80CpuMonALS.vhd

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-- Copyright (c) 2019 David Banks
--
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--   ____  ____
--  /   /\/   /
-- /___/  \  /
-- \   \   \/
--  \   \
--  /   /         Filename  : Z80CpuMonALS.vhd
-- /___/   /\     Timestamp : 29/09/2019
-- \   \  /  \
--  \___\/\___\
--
--Design Name: Z80CpuMon
--Device: XC6SLX9

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.numeric_std.all;

entity Z80CpuMonALS is
    generic (
        num_comparators   : integer := 8;        -- default value for lx9core board
        avr_prog_mem_size : integer := 1024 * 16 -- default value for lx9core board
        );
    port (
        clock           : in    std_logic;

        -- Z80 Signals
        RESET_n         : in    std_logic;
        CLK_n           : in    std_logic;
        WAIT_n          : in    std_logic;
        INT_n           : in    std_logic;
        NMI_n           : in    std_logic;
        BUSRQ_n         : in    std_logic;
        M1_n            : out   std_logic;
        MREQ_n          : out   std_logic;
        IORQ_n          : out   std_logic;
        RD_n            : out   std_logic;
        WR_n            : out   std_logic;
        RFSH_n          : out   std_logic;
        HALT_n          : out   std_logic;
        BUSAK_n         : out   std_logic;
        Addr            : out   std_logic_vector(15 downto 0);
        Data            : inout std_logic_vector(7 downto 0);

        -- Level Shifers Controls
        OEC_n           : out   std_logic;
        OEA1_n          : out   std_logic;
        OEA2_n          : out   std_logic;
        OED_n           : out   std_logic;
        DIRD            : out   std_logic;

        -- External trigger inputs
        trig            : in    std_logic_vector(1 downto 0);

        -- ID/mode inputs
        mode            : in    std_logic;
        id              : in    std_logic_vector(3 downto 0);

        -- Serial Console
        avr_RxD         : in    std_logic;
        avr_TxD         : out   std_logic;

        -- Switches
        sw1             : in    std_logic;
        sw2             : in    std_logic;

        -- LEDs
        led1            : out   std_logic;
        led2            : out   std_logic;
        led3            : out   std_logic;

        -- Optional OHO_DY1 connected to test connector
        tmosi           : out   std_logic;
        tdin            : out   std_logic;
        tcclk           : out   std_logic;

        -- Optional Debugging signals
        test            : out   std_logic_vector(9 downto 0)

        );
end Z80CpuMonALS;

architecture behavioral of Z80CpuMonALS is

    signal MREQ_n_int   : std_logic;
    signal IORQ_n_int   : std_logic;
    signal M1_n_int     : std_logic;
    signal RD_n_int     : std_logic;
    signal WR_n_int     : std_logic;
    signal RFSH_n_int   : std_logic;
    signal HALT_n_int   : std_logic;
    signal BUSAK_n_int  : std_logic;
    signal tristate_n   : std_logic;
    signal tristate_ad_n: std_logic;

    signal sw_reset_cpu : std_logic;
    signal sw_reset_avr : std_logic;
    signal led_bkpt     : std_logic;
    signal led_trig0    : std_logic;
    signal led_trig1    : std_logic;

    signal TState       : std_logic_vector(2 downto 0);
begin

    sw_reset_cpu <= not sw1;
    sw_reset_avr <= not sw2;
    led1         <= led_bkpt;
    led2         <= led_trig0;
    led3         <= led_trig1;

    MREQ_n  <= MREQ_n_int;
    IORQ_n  <= IORQ_n_int;
    M1_n    <= M1_n_int;
    RD_n    <= RD_n_int;
    WR_n    <= WR_n_int;
    RFSH_n  <= RFSH_n_int;
    HALT_n  <= HALT_n_int;
    BUSAK_n <= BUSAK_n_int;

    OEC_n   <= not tristate_n;
    OEA1_n  <= not tristate_ad_n;
    OEA2_n  <= not tristate_ad_n;
    OED_n   <= not tristate_ad_n;

    wrapper : entity work.Z80CpuMon
        generic map (
            ClkMult           => 12,
            ClkDiv            => 25,
            ClkPer            => 20.000,
            num_comparators   => num_comparators,
            avr_prog_mem_size => avr_prog_mem_size
            )
        port map (
            clock             => clock,

            -- Z80 Signals
            RESET_n           => RESET_n,
            CLK_n             => CLK_n,
            WAIT_n            => WAIT_n,
            INT_n             => INT_n,
            NMI_n             => NMI_n,
            BUSRQ_n           => BUSRQ_n,
            M1_n              => M1_n_int,
            MREQ_n            => MREQ_n_int,
            IORQ_n            => IORQ_n_int,
            RD_n              => RD_n_int,
            WR_n              => WR_n_int,
            RFSH_n            => RFSH_n_int,
            HALT_n            => HALT_n_int,
            BUSAK_n           => BUSAK_n_int,
            Addr              => Addr,
            Data              => Data,

            -- Buffer Control Signals
            DIRD              => DIRD,
            tristate_n        => tristate_n,
            tristate_ad_n     => tristate_ad_n,

            -- Mode jumper, tie low to generate NOPs when paused
            mode              => mode,

            -- External trigger inputs
            trig              => trig,

            -- Serial Console
            avr_RxD           => avr_RxD,
            avr_TxD           => avr_TxD,

            -- Switches
            sw_reset_cpu      => sw_reset_cpu,
            sw_reset_avr      => sw_reset_avr,

            -- LEDs
            led_bkpt          => led_bkpt,
            led_trig0         => led_trig0,
            led_trig1         => led_trig1,

            -- OHO_DY1 connected to test connector
            tmosi             => tmosi,
            tdin              => tdin,
            tcclk             => tcclk,

            -- Debugging signals
            test1             => open,
            test2             => TState(0),
            test3             => TState(1),
            test4             => TSTate(2)
            );

    -- Test outputs
    test(0) <= M1_n_int;
    test(1) <= RD_n_int;
    test(2) <= WR_n_int;
    test(3) <= MREQ_n_int;
    test(4) <= IORQ_n_int;
    test(5) <= WAIT_n;
    test(6) <= CLK_n;
    test(7) <= TState(2);
    test(8) <= TState(1);
    test(9) <= TState(0);

end behavioral;