Self check 8 bit shifter in VHDL

[Magman]

Hi everyone
I need your help to build a self check 8bit shifter.
Generally my idea is to use crc8 generator to encode input data. I used such module in my project.
Everything to this point is great, i receive correct crc values (8 bit) from generator (I compared it with CRC8 calculator in the internet).
But then i need to shift it. I don't know how to perform arithmetic operations on the data with checksum.
After shifting there will be wrong checksum.
Maybe there is a better way to create sc shift register than using CRC?
Thanks in advance!

 

[naught]

I have done similar module before, input 2024 bits data and get 24 bits crc check sum.

I designed a state machine with s0, s1, s2 phase, s0 is the initial phase and reset everything; s1 do the check sum calculation and ouput the original data; s2 do the check sum output.
when in s1, the register is enabled, thus the check sum keeps changing
when it comes to s2, the register is not enabled and thus hold the final check sum.
then you can use mux to output the check sum as you wish.


hope this might help...

 

[Magman]

Thank you for your help, your idea is very helpful. My project is almost done.