Cut one at a framebuffer

[fpgaboy.git] / Framebuffer.v

diff --git a/Framebuffer.v b/Framebuffer.v
new file mode 100644 (file)
index 0000000..836f73a
--- /dev/null
+++ b/Framebuffer.v
@@ -0,0 +1,78 @@
+`define XRES 640
+`define XFPORCH 16
+`define XSYNC 96
+`define XBPORCH 48
+`define YRES 480
+`define YFPORCH 10
+`define YSYNC 2
+`define YBPORCH 29
+
+`define XOFS ((640-160)/2)
+`define YOFS ((480-144)/2)
+
+module Framebuffer(
+       input lcdclk,
+       input lcdvs, lcdhs,
+       input [2:0] lcdr, lcdg, input [1:0] lcdb,
+       
+       input vgaclk,
+       output reg vgavs, vgahs,
+       output wire [2:0] vgar, vgag, output wire [1:0] vgab);
+       
+       reg [2:0] fb [23039:0];
+       
+       reg [7:0] lcdx = 8'h00;
+       reg [7:0] lcdy = 8'h00;
+       reg [15:0] lcdfb = 16'h0000;
+       
+       always @(posedge lcdclk)
+       begin
+               /* We use BLOCKING assigns here. */
+               if (lcdvs) begin
+                       lcdx <= 0;
+                       lcdy <= 0;
+                       lcdfb <= 0;
+               end else if (lcdhs) begin
+                       lcdx <= 0;
+                       lcdy <= lcdy + 1;
+               end else if (lcdx < 160) begin
+                       lcdx <= lcdx + 1;
+                       lcdfb <= lcdfb + 1;
+               end
+       end
+       
+       reg [11:0] vgax = 0, vgay = 0;
+       reg [15:0] vgafb = 16'h0000;
+       
+       reg [2:0] failandloss;
+       assign {vgar, vgag, vgab} =
+               ((vgax > `XOFS) && (vgax < (`XOFS + 160)) && (vgay > `YOFS) && (vgay < (`YOFS + 144))) ? {failandloss[2],2'b0,failandloss[1],2'b0,failandloss[0],1'b0} :
+               ((vgax < 640) && (vgay < 480)) ? 8'b11100000 :
+               8'b00000000;
+       
+       always @(posedge vgaclk)
+       begin
+               if (vgax >= (`XRES + `XFPORCH + `XSYNC + `XBPORCH))
+               begin
+                       if (vgay >= (`YRES + `YFPORCH + `YSYNC + `YBPORCH)) begin
+                               vgafb <= 0;
+                               vgay <= 0;
+                       end else
+                               vgay <= vgay + 1;
+                       vgax <= 0;
+               end else
+                       vgax <= vgax + 1;
+               
+               vgahs <= (vgax >= (`XRES + `XFPORCH)) && (vgax < (`XRES + `XFPORCH + `XSYNC));
+               vgavs <= (vgay >= (`YRES + `YFPORCH)) && (vgay < (`YRES + `YFPORCH + `YSYNC));
+               
+               if ((vgax > `XOFS) && (vgax < (`XOFS + 160)) && (vgay > `YOFS) && (vgay < (`YOFS + 144))) begin
+                       vgafb <= vgafb + 1;
+                       failandloss <= fb[vgafb + 1];
+               end
+               
+               // Need thsi here; vgaclk >>> lcdclk
+               if ((lcdy < 144) && (lcdx < 160))
+                       fb[lcdfb] <= {lcdr[2], lcdg[2], lcdb[1]};
+       end
+endmodule