Super video graphics adaptor (SVGA) analog framestore output port.
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reg [2:0] framestore[32767:0];
reg [7:0] hptr, vptr;
output reg [2:0] rgb_video;
output reg hsynch, vsynch;
always @(posedge clk) begin
hptr <= (hsynch) ? 0: hptr + 1;
hsynch <= (hptr >= 230)
if (hsynch) vptr <= (vsynch) ? 0: vptr + 1;
vsynch <= (vptr == 110)
if (hwen) framestore[haddr]<= wdata[2:0];
/*else*/ rgb_video <= framestore[{vptr[6:0], hptr}];
end
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Alternate design uses main system RAM instead of a private SRAM (need a small staging FIFO).
The pixel clock rate, H/W dimensions and synch pulse widths are normally programmable.
The RAM cannot be read. Moreover it has two address ports: re-code with one arbitrated port ?
| 39: (C) 2008-18, DJ Greaves, University of Cambridge, Computer Laboratory. |