2 Replies Latest reply on Jul 25, 2018 2:36 AM by MaTr_1730276

# PRS

Hello,

I'm developing a system using a PRS component set to 17 bit.

With 17 bit I can reach 2^17 = 131071 combination.

I have no problems regard the decoding (my system read a code of 17 bit and decode by means of PRS the combination).

I need a firmware routine that generate the 131071 combination because I have to print the entire combination on an external support (that my system have to read).

Could you provide a generic firmware routine that generate the 17 bit sequence as PRS component ("generic" because I have to provide the routine to my supplier that using a standard MCU and not a sOC)?

Thanks and regards

• ###### 1. Re: PRS

Hi,

Normally LFSR is used to generate psuedo random sequence generator.

If your requirement is to go through all the 2^17 combinations, a simple counter output might do the job.

If you want to generate a random sequence, same logic can be replicated in firmware.

For a 10 bit random sequence generator

for(i=0; i<11; i++) b[i] = 1<<i;

Then pick a primitive polynomial (x^10 + x^3 + 1 is an example)

Start with a seed for x, say

x = 0x8;

rotate x to the left, and copy the exclusive or of bits 10, 3 and 0 into

bit 0:

y1 = (b[10] & x) ? 1 : 0;

y2 = (b[3] & x) ? 1 : 0;

y3 = (b[0] & x) ? 1 : 0;

x = x << 1 | (y1 ^ y2 ^ y3);

• ###### 2. Re: PRS

Thank you!

Manuel Trotta

Technical department