Subversion Repositories ag_6502

`timescale 1ns / 1ps

//////////////////////////////////////////////////////////////////////////////////

// Company:   BMSTU

// Engineer:  Oleg Odintsov

// 

// Create Date:    15:09:47 01/19/2012 

// Design Name: 

// Module Name:    ag_main

// Project Name:    Agat Hardware Project

// Target Devices: 

// Tool versions: 

// Description: 

//

// Dependencies: 

//

// Revision: 

// Revision 0.01 - File Created

// Additional Comments: 

//

//////////////////////////////////////////////////////////////////////////////////

module RAM2kx8(input CLK, input[10:0] AB, input CS, input READ, output[7:0] DO, input[7:0] DI);

        reg[7:0] mem[0:2047];

        reg[7:0] R;

        assign DO = CS? R: 8'bZ;

        initial begin

                `include "monitor7.v"

                mem['h7FC] = 8'h00;

                mem['h7FD] = 8'h50;

        end

        always @(posedge CLK) if (CS) if (READ) R <= mem[AB]; else mem[AB] <= DI;

endmodule

module RAM4kx8(input CLK, input[11:0] AB, input CS, input READ, output[7:0] DO, input[7:0] DI);

        reg[7:0] mem[0:4095];

        reg[7:0] R;

        assign DO = CS? R: 8'bZ;

        always @(posedge CLK) if (CS) if (READ) R <= mem[AB]; else mem[AB] <= DI;

endmodule

module RAM8kx8(input CLK, input[12:0] AB, input CS, input READ, output[7:0] DO, input[7:0] DI);

        reg[7:0] mem[0:8191];

        reg[7:0] R;

        assign DO = CS? R: 8'bZ;

        always @(posedge CLK) if (CS) if (READ) R <= mem[AB]; else mem[AB] <= DI;

endmodule

module ag_main(

    input clk50,

         input[3:0] btns,

         output[7:0] leds,

         output[3:0] controls,

         output[4:0] vga_bus,

         input[1:0] ps2_bus_in,

         output clk_cpu

    );

//      assign leds = 0;

//      assign controls = 0;

//      assign vga_bus = 0;

        wire clk1, clk10;

        clk_div#5 cd5(clk50, clk10);

   clk_div#10 cd10(clk10, clk1);

        wire clk_vram;

        wire[13:0] AB2;

        wire[15:0] DI2;

        wire [15:0] AB;  // address bus

        wire [7:0] DI;           // data in, read bus

        wire [7:0] DO;           // data out, write bus

        wire read;

        wire rom_cs, ram_cs, xram_cs;

        wire phi_1, phi_2;

        RAM32Kx8x16 base_ram(phi_2, AB[14:0], ram_cs, read, DI, DO,

                                                        clk_vram, AB2, 1, DI2);

        RAM2kx8 rom1(phi_2, AB[10:0], rom_cs, read, DI, DO);

        RAM8kx8 xram(phi_2, AB[12:0], xram_cs, read, DI, DO);

        wire [3:0] AB_HH = AB[15:12];

        wire [3:0] AB_HL = AB[11:8];

        wire [3:0] AB_LH = AB[7:4];

        wire [3:0] AB_LL = AB[3:0];

        wire [7:0] AB_H = AB[15:8];

        wire [7:0] AB_L = AB[7:0];

        wire AB_CXXX = (AB_HH == 4'hC);

        wire AB_FXXX = (AB_HH == 4'hF);

        wire AB_C0XX = AB_CXXX && !AB_HL;

        wire AB_C00X = AB_C0XX && (AB_LH == 4'h0);

        wire AB_C01X = AB_C0XX && (AB_LH == 4'h1);

        wire AB_C02X = AB_C0XX && (AB_LH == 4'h2);

        wire AB_C03X = AB_C0XX && (AB_LH == 4'h3);

        wire AB_C7XX = AB_CXXX && (AB_HL == 4'h7);

        assign rom_cs = AB_FXXX && AB[11]; // F800-FFFF

        assign ram_cs = !AB[15];

        assign xram_cs = (AB_HH[3:1] == 3'b100);

        reg reset_auto = 1;

        wire reset;

        wire WE = ~read;                // write enable

        supply0 IRQ;            // interrupt request

        supply0 NMI;            // non-maskable interrupt request

        supply1 RDY;            // Ready signal. Pauses CPU when RDY=0 

        supply1 SO;                     // Set Overflow, not used.

        wire SYNC;

        reg[7:0] vmode = 0;

        wire[7:0] key_reg;

        reg[7:0] b_reg;

        reg lb;

        wire key_rus;

        reg key_clear = 0;

        wire key_rst, key_pause;

        reg beep_reg = 0, tape_out_reg = 0;

        assign reset  = 0;//btns[0];

        assign leds = AB[11:4];

        assign controls = {1'b0, beep_reg ^ tape_out_reg, tape_out_reg, beep_reg};

        ag_video video(clk50, vmode, clk_vram, AB2, DI2, vga_bus);

        wire[1:0] ps2_bus;

        signal_filter sf1(clk1, ps2_bus_in[0], ps2_bus[0]);

        signal_filter sf2(clk1, ps2_bus_in[1], ps2_bus[1]);

        ag_keyb keyb(phi_2, ps2_bus, key_reg, key_clear, key_rus, key_rst, key_pause);

        assign DI = (AB_C00X && !WE)?b_reg?b_reg:key_reg:8'bZ;

        always @(posedge phi_2) begin

                key_clear <= AB_C01X;

                if (AB_C01X) b_reg <= 0;

                if (btns[2] & ~lb) b_reg <= 8'hDD;

                else if (btns[0]) b_reg <= 8'h9C;

                else if (btns[1]) b_reg <= 8'hA0;

                else if (btns[3]) b_reg <= 8'h93;

                lb <= btns[2];

                if (AB_C02X) tape_out_reg <= ~tape_out_reg;

                if (AB_C03X) beep_reg <= ~beep_reg;

                if (AB_C7XX) vmode <= AB_L;

        end

        always @(posedge vga_bus[0]) begin

                reset_auto <= 0;

        end

        ag6502_ext_clock clk(clk50, clk1, phi_1, phi_2);

        ag6502 cpu(clk1, phi_1, phi_2, AB, read, DI, DO,

                                        RDY & ~key_pause, ~(reset | reset_auto | key_rst), ~IRQ, ~NMI, SO, SYNC);

        assign clk_cpu = clk1;

endmodule