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/random_pulse_generator/trunk/random_pulse_generator.v
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/////////////////////////////////////////////////////////////////////////////////////////////////// |
// |
// File: random_pulse_generator.v |
// File history: |
// Version 1: 2015-03-24: Created |
// |
// Description: |
// |
// Poisson process generator. |
// Generate Poisson process with desired inversed rate (number of clocks per hit). |
// The rate is defined by parameter LN2_PERIOD. For example, the LN2_PERIOD=4 will generate |
// in average one pulse per 16 clocks. |
// |
// Author: Andrey Sukhanov |
// |
/////////////////////////////////////////////////////////////////////////////////////////////////// |
`timescale 1ns/1ps |
|
//'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' |
module pseudo_random(input clk, ce, rst, output reg [31:0] q); |
// 32-bit uniform pseudo-random number generator, based on fibonacci LFSR |
// Other 32-bit uniform random generators can be used as well. |
|
wire feedback = q[31]^q[29]^q[28]^ q[27]^ q[23]^q[20]^ q[19]^q[17]^ q[15]^q[14]^q[12]^ q[11]^q[9]^ q[4]^ q[3]^q[2]; |
//feedback term B89ADA1C, other terms can be found from this table |
// http://www.ece.cmu.edu/~koopman/lfsr/index.html |
|
always @(posedge clk or posedge rst) |
if (rst) |
q <= 32'haaaaaaaa; // the start is more random with this initialization |
else if (ce) |
q <= {q[30:0], feedback} ; |
endmodule |
//,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, |
//'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' |
module random_pulse_generator( input clk, ce, rst, output reg q); |
|
parameter LN2_PERIOD = 4; // 1 < LN2_PERIOD < 31 |
// log2 of the inversed process rate , |
|
parameter MASK = {LN2_PERIOD{1'b0}}; // any number with LN2_PERIOD bits can be used as a MASK |
wire [31:0] uniform_random; |
wire [LN2_PERIOD-1:0] sample; |
pseudo_random pseudo_random_gen(clk, ce, rst, uniform_random); |
|
assign sample = uniform_random[LN2_PERIOD-1:0]; // any subset of LN2_PERIOD bits can be used as a sample |
always @ (posedge clk) |
if(ce) begin |
if (sample == MASK) q <= 1'b1; |
if (q) q <= 1'b0; |
end |
endmodule |
//,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, |
random_pulse_generator/trunk/random_pulse_generator.v
Property changes :
Added: svn:executable
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