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8bitworkshop/presets/verilog/starfield.v
2018-02-18 11:14:04 -06:00

37 lines
722 B
Verilog

`include "hvsync_generator.v"
`include "lfsr.v"
module starfield_top(clk, reset, hsync, vsync, rgb);
input clk, reset;
output hsync, vsync;
output [2:0] rgb;
wire display_on;
wire [8:0] hpos;
wire [8:0] vpos;
wire [15:0] lfsr;
hvsync_generator hvsync_gen(
.clk(clk),
.reset(reset),
.hsync(hsync),
.vsync(vsync),
.display_on(display_on),
.hpos(hpos),
.vpos(vpos)
);
wire star_enable = !hpos[8] & !vpos[8];
// LFSR with period = 2^16-1 = 256*256-1
LFSR #(16,16'b1000000001011,0) lfsr_gen(
.clk(clk),
.reset(reset),
.enable(star_enable),
.lfsr(lfsr));
wire star_on = &lfsr[15:9];
assign rgb = display_on && star_on ? lfsr[2:0] : 0;
endmodule