X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/2854e3991ab66f6fb954aba96caf7875d049431e..49c326da841985a8aa48e8544173e5c045c6e0eb:/System.v diff --git a/System.v b/System.v index 1872e51..8c4cf1a 100644 --- a/System.v +++ b/System.v @@ -6,6 +6,7 @@ module ROM( input clk, input wr, rd); + reg rdlatch = 0; reg [7:0] odata; // synthesis attribute ram_style of rom is block @@ -13,9 +14,11 @@ module ROM( initial $readmemh("rom.hex", rom); wire decode = address[15:13] == 0; - always @(posedge clk) + always @(posedge clk) begin + rdlatch <= rd && decode; odata <= rom[address[10:0]]; - assign data = (rd && decode) ? odata : 8'bzzzzzzzz; + end + assign data = rdlatch ? odata : 8'bzzzzzzzz; endmodule module BootstrapROM( @@ -24,12 +27,24 @@ module BootstrapROM( input clk, input wr, rd); - reg [7:0] brom [255:0]; - initial $readmemh("bootstrap.hex", brom); + reg rdlatch = 0; + reg [7:0] addrlatch = 0; + reg romno = 0, romnotmp = 0; + reg [7:0] brom0 [255:0]; + reg [7:0] brom1 [255:0]; + + initial $readmemh("fpgaboot.hex", brom0); + initial $readmemh("gbboot.hex", brom1); wire decode = address[15:8] == 0; - wire [7:0] odata = brom[address[7:0]]; - assign data = (rd && decode) ? odata : 8'bzzzzzzzz; + wire [7:0] odata = (romno == 0) ? brom0[addrlatch] : brom1[addrlatch]; + always @(posedge clk) begin + rdlatch <= rd && decode; + addrlatch <= address[7:0]; + if (wr && decode) romnotmp <= data[0]; + if (rd && address == 16'h0000) romno <= romnotmp; /* Latch when the program restarts. */ + end + assign data = rdlatch ? odata : 8'bzzzzzzzz; endmodule module MiniRAM( @@ -41,13 +56,15 @@ module MiniRAM( reg [7:0] ram [127:0]; wire decode = (address >= 16'hFF80) && (address <= 16'hFFFE); + reg rdlatch = 0; reg [7:0] odata; - assign data = (rd && decode) ? odata : 8'bzzzzzzzz; + assign data = rdlatch ? odata : 8'bzzzzzzzz; always @(posedge clk) begin - if (decode) // This has to go this way. The only way XST knows how to do - begin // block ram is chip select, write enable, and always + rdlatch <= rd && decode; + if (decode) // This has to go this way. The only way XST knows how to do + begin // block ram is chip select, write enable, and always if (wr) // reading. "else if rd" does not cut it ... ram[address[6:0]] <= data; odata <= ram[address[6:0]]; @@ -55,6 +72,66 @@ module MiniRAM( end endmodule +module CellularRAM( + input clk, + input [15:0] address, + inout [7:0] data, + input wr, rd, + output wire cr_nADV, cr_nCE, cr_nOE, cr_nWE, cr_CRE, cr_nLB, cr_nUB, cr_CLK, + output wire [22:0] cr_A, + inout [15:0] cr_DQ); + + parameter ADDR_PROGADDRH = 16'hFF60; + parameter ADDR_PROGADDRM = 16'hFF61; + parameter ADDR_PROGADDRL = 16'hFF62; + parameter ADDR_PROGDATA = 16'hFF63; + + reg rdlatch = 0, wrlatch = 0; + reg [15:0] addrlatch = 0; + reg [7:0] datalatch = 0; + + reg [7:0] progaddrh, progaddrm, progaddrl; + + assign cr_nADV = 0; /* Addresses are always valid! :D */ + assign cr_nCE = 0; /* The chip is enabled */ + assign cr_nLB = 0; /* Lower byte is enabled */ + assign cr_nUB = 0; /* Upper byte is enabled */ + assign cr_CRE = 0; /* Data writes, not config */ + assign cr_CLK = 0; /* Clock? I think not! */ + + wire decode = (addrlatch[15:14] == 2'b00) /* extrom */ || (addrlatch[15:13] == 3'b101) /* extram */ || (addrlatch == ADDR_PROGDATA); + + assign cr_nOE = decode ? ~rdlatch : 1; + assign cr_nWE = decode ? ~wrlatch : 1; + + assign cr_DQ = (~cr_nOE) ? 16'bzzzzzzzzzzzzzzzz : {8'b0, datalatch}; + assign cr_A = (addrlatch[15:14] == 2'b00) ? /* extrom */ {9'b0,addrlatch[13:0]} : + (addrlatch[15:13] == 3'b101) ? {1'b1, 9'b0, addrlatch[12:0]} : + (addrlatch == ADDR_PROGDATA) ? {progaddrh[6:0], progaddrm[7:0], progaddrl[7:0]} : + 23'b0; + + reg [7:0] regbuf; + + always @(posedge clk) begin + case (address) + ADDR_PROGADDRH: if (wr) progaddrh <= data; + ADDR_PROGADDRM: if (wr) progaddrm <= data; + ADDR_PROGADDRL: if (wr) progaddrl <= data; + endcase + rdlatch <= rd; + wrlatch <= wr; + addrlatch <= address; + datalatch <= data; + end + + assign data = (rdlatch && decode) ? + (addrlatch == ADDR_PROGADDRH) ? progaddrh : + (addrlatch == ADDR_PROGADDRM) ? progaddrm : + (addrlatch == ADDR_PROGADDRL) ? progaddrl : + cr_DQ + : 8'bzzzzzzzz; +endmodule + module InternalRAM( input [15:0] address, inout [7:0] data, @@ -64,14 +141,16 @@ module InternalRAM( // synthesis attribute ram_style of ram is block reg [7:0] ram [8191:0]; - wire decode = address[15:13] == 3'b110; + wire decode = (address >= 16'hC000) && (address <= 16'hFDFF); /* This includes echo RAM. */ reg [7:0] odata; - assign data = (rd && decode) ? odata : 8'bzzzzzzzz; + reg rdlatch = 0; + assign data = rdlatch ? odata : 8'bzzzzzzzz; always @(posedge clk) begin - if (decode) // This has to go this way. The only way XST knows how to do - begin // block ram is chip select, write enable, and always + rdlatch <= rd && decode; + if (decode) // This has to go this way. The only way XST knows how to do + begin // block ram is chip select, write enable, and always if (wr) // reading. "else if rd" does not cut it ... ram[address[12:0]] <= data; odata <= ram[address[12:0]]; @@ -89,10 +168,12 @@ module Switches( wire decode = address == 16'hFF51; reg [7:0] odata; - assign data = (rd && decode) ? odata : 8'bzzzzzzzz; + reg rdlatch = 0; + assign data = rdlatch ? odata : 8'bzzzzzzzz; always @(posedge clk) begin + rdlatch <= rd && decode; if (decode && rd) odata <= switches; else if (decode && wr) @@ -117,6 +198,9 @@ module CoreTop( output serio, output wire [3:0] digits, output wire [7:0] seven, + output wire cr_nADV, cr_nCE, cr_nOE, cr_nWE, cr_CRE, cr_nLB, cr_nUB, cr_CLK, + output wire [22:0] cr_A, + inout [15:0] cr_DQ, `endif output wire hs, vs, output wire [2:0] r, g, @@ -171,12 +255,31 @@ module CoreTop( .wr(wr[1]), .rd(rd[1])); +`ifdef isim ROM rom( .address(addr[0]), .data(data[0]), .clk(clk), .wr(wr[0]), .rd(rd[0])); +`else + CellularRAM cellram( + .address(addr[0]), + .data(data[0]), + .clk(clk), + .wr(wr[0]), + .rd(rd[0]), + .cr_nADV(cr_nADV), + .cr_nCE(cr_nCE), + .cr_nOE(cr_nOE), + .cr_nWE(cr_nWE), + .cr_CRE(cr_CRE), + .cr_nLB(cr_nLB), + .cr_nUB(cr_nUB), + .cr_CLK(cr_CLK), + .cr_A(cr_A), + .cr_DQ(cr_DQ)); +`endif wire lcdhs, lcdvs, lcdclk; wire [2:0] lcdr, lcdg;