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Adding basic limits to random number generator

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aolofsson 2022-06-17 15:09:32 -04:00
parent 70bbde9ccb
commit d380374049
1 changed files with 5 additions and 3 deletions
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8
src/stdlib/hdl/oh_random.v
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@ -6,11 +6,13 @@
//############################################################################# //#############################################################################
module oh_random module oh_random
#(parameter N = 32 //width of counter (max value) #(parameter N = 32, //width of counter (max value)
parameter SEED = 32'haaaaaaaa //non zero number to start with
) )
( (
input clk, input clk,
input nreset, //async reset input nreset, //async reset
input [N-1:0] mask, //mask output to limit range
input en, //enable counter input en, //enable counter
output [N-1:0] out //random output pulse output [N-1:0] out //random output pulse
); );
@ -30,7 +32,7 @@ module oh_random
// counter // counter
always @(posedge clk or negedge nreset) always @(posedge clk or negedge nreset)
if(~nreset) if(~nreset)
lfsr_reg[N-1:0] <= {(N/2){2'b01}}; lfsr_reg[N-1:0] <= SEED;
else if(en) else if(en)
lfsr_reg[N-1:0] <= lfsr_in[N-1:0]; lfsr_reg[N-1:0] <= lfsr_in[N-1:0];
@ -42,7 +44,7 @@ module oh_random
assign lfsr_in[i] = taps_sel[i] ? (lfsr_reg[i-1] ^ feedback) : assign lfsr_in[i] = taps_sel[i] ? (lfsr_reg[i-1] ^ feedback) :
lfsr_reg[i-1]; lfsr_reg[i-1];
assign out[N-1:0] = lfsr_reg[N-1:0]; assign out[N-1:0] = mask[N-1:0] & lfsr_reg[N-1:0];
endmodule // oh_random endmodule // oh_random