System.v

   1
   2 `timescale 1ns / 1ps
   3 module ROM(
   4         input [15:0] address,
   5         inout [7:0] data,
   6         input clk,
   7         input wr, rd);
   8
   9         reg [7:0] rom [2047:0];
  10         initial $readmemh("rom.hex", rom);
  11
  12         wire decode = address[15:13] == 0;
  13         wire [7:0] odata = rom[address[11:0]];
  14         assign data = (rd && decode) ? odata : 8'bzzzzzzzz;
  15         //assign data = rd ? odata : 8'bzzzzzzzz;
  16 endmodule
  17
  18 module InternalRAM(
  19         input [15:0] address,
  20         inout [7:0] data,
  21         input clk,
  22         input wr, rd);
  23
  24         // synthesis attribute ram_style of reg is block
  25         reg [7:0] ram [8191:0];
  26
  27         wire decode = address[15:13] == 3'b110;
  28         reg [7:0] odata;
  29         wire idata = data;
  30         assign data = (rd && decode) ? odata : 8'bzzzzzzzz;
  31
  32         always @(negedge clk)
  33         begin
  34                 if (decode)     // This has to go this way. The only way XST knows how to do
  35                 begin                           // block ram is chip select, write enable, and always
  36                         if (wr)         // reading. "else if rd" does not cut it ...
  37                                 ram[address[12:0]] <= data;
  38                         odata <= ram[address[12:0]];
  39                 end
  40         end
  41 endmodule
  42
  43 module Switches(
  44         input [15:0] address,
  45         inout [7:0] data,
  46         input clk,
  47         input wr, rd,
  48         input [7:0] switches,
  49         output reg [7:0] ledout);
  50
  51         wire decode = address == 16'hFF51;
  52         reg [7:0] odata;
  53         assign data = (rd && decode) ? odata : 8'bzzzzzzzz;
  54
  55         always @(negedge clk)
  56         begin
  57                 if (decode && rd)
  58                         odata <= switches;
  59                 else if (decode && wr)
  60                         ledout <= data;
  61         end
  62 endmodule
  63
  64 module CoreTop(
  65         input xtal,
  66         input [7:0] switches,
  67         input [3:0] buttons,
  68         output wire [7:0] leds,
  69         output serio,
  70         output wire [3:0] digits,
  71         output wire [7:0] seven);
  72
  73         wire clk;
  74         //IBUFG ibuf (.O(clk), .I(iclk));
  75
  76         CPUDCM dcm (.CLKIN_IN(xtal), .CLKFX_OUT(clk));
  77
  78         wire [15:0] addr;
  79         wire [7:0] data;
  80         wire wr, rd;
  81
  82         GBZ80Core core(
  83                 .clk(clk),
  84                 .busaddress(addr),
  85                 .busdata(data),
  86                 .buswr(wr),
  87                 .busrd(rd));
  88
  89         ROM rom(
  90                 .address(addr),
  91                 .data(data),
  92                 .clk(clk),
  93                 .wr(wr),
  94                 .rd(rd));
  95
  96         AddrMon amon(
  97     .addr(addr),
  98     .clk(clk),
  99     .digit(digits),
 100     .out(seven),
 101          .freeze(buttons[0])
 102     );
 103
 104         Switches sw(
 105                 .address(addr),
 106                 .data(data),
 107                 .clk(clk),
 108                 .wr(wr),
 109                 .rd(rd),
 110                 .ledout(leds),
 111                 .switches(switches)
 112                 );
 113
 114         UART nouart (
 115     .clk(clk),
 116     .wr(wr),
 117     .rd(rd),
 118     .addr(addr),
 119     .data(data),
 120     .serial(serio)
 121     );
 122
 123   InternalRAM ram(
 124                 .address(addr),
 125                 .data(data),
 126                 .clk(clk),
 127                 .wr(wr),
 128                 .rd(rd));
 129 endmodule
 130
 131 module TestBench();
 132         reg clk = 0;
 133         wire [15:0] addr;
 134         wire [7:0] data;
 135         wire wr, rd;
 136
 137 //      wire [7:0] leds;
 138 //      wire [7:0] switches;
 139
 140         always #10 clk <= ~clk;
 141         GBZ80Core core(
 142                 .clk(clk),
 143                 .busaddress(addr),
 144                 .busdata(data),
 145                 .buswr(wr),
 146                 .busrd(rd));
 147
 148         ROM rom(
 149                 .clk(clk),
 150                 .address(addr),
 151                 .data(data),
 152                 .wr(wr),
 153                 .rd(rd));
 154
 155         InternalRAM ram(
 156                 .address(addr),
 157                 .data(data),
 158                 .clk(clk),
 159                 .wr(wr),
 160                 .rd(rd));
 161
 162         wire serio;
 163         UART uart(
 164                 .addr(addr),
 165                 .data(data),
 166                 .clk(clk),
 167                 .wr(wr),
 168                 .rd(rd),
 169                 .serial(serio));
 170
 171 //      Switches sw(
 172 //              .clk(clk),
 173 //              .address(addr),
 174 //              .data(data),
 175 //              .wr(wr),
 176 //              .rd(rd),
 177 //              .switches(switches),
 178 //              .leds(leds));
 179 endmodule