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8bitworkshop/presets/verilog/lfsr.v
2018-02-16 23:33:29 -06:00

27 lines
483 B
Verilog

`ifndef LFSR_V
`define LFSR_V
module LFSR(clk,reset,enable,lfsr);
parameter NBITS = 8;
parameter TAPS = 8'b11101;
parameter INVERT = 0;
input clk, reset;
input enable;
output reg [NBITS-1:0] lfsr;
wire feedback = lfsr[NBITS-1] ^ INVERT;
always @(posedge clk)
begin
if (reset) // initialize to 1
lfsr <= {lfsr[NBITS-2:1], 1'b0, 1'b1};
else if (enable)
lfsr <= {lfsr[NBITS-2:0], 1'b0} ^ (feedback ? TAPS : 0);
end
endmodule
`endif