CRC-problem

[Anonymous]

 Hello All

   

I am using CRC component . The polynomial selected is x¹⁶+x¹⁵+x²+1. I am feeding the data serially via shift register.

   

When the data is 0xFF the result is perfect 0202. But when the data is other than this value the result is some junk..Can any one help in this.

[Anonymous]

how about uploading your project for people to check.

[ETRO_SSN583]

This might be of help -

       

http://www.cypress.com/?id=4&rID=60792

       

Regards, Dana.

[ETRO_SSN583]

Retract the earlier post, that was for PSOC 1.

       

Regards, Dana.

[ETRO_SSN583]

This ap note has a CRC example as part of the overall project discussion -

       

http://www.cypress.com/?rID=61356

       

Regards, Dana.

[Anonymous]

A good reference to CRC

   

 http://www.ross.net/crc/download/crc_v3.txt

   

Please noted that the seed and the direction (ie MSB first or LSB first) would affect the operation of CRC. 

   

enjoy the reading 🙂

[Anonymous]

 I figured out the problem.... There was problem in sending the data out and being read by CRC(setup and hold time problem).

   

Everything is working fine but i have a new problem now.....

   

CRC result is correct only for the first time(when first data byte is entered into CRC)... later on even after Stoipping the component and starting it again for second time or seeding with zeros after 1st CRC calculation the results are not proper for the second time......

   

Why is this, i will be attaching the project...

[Bob_Marlowe]

Did you use the CRC_Init() API ?

       

Bob

[Anonymous]

 I have used 

   

CRC_Stop and CRC_Start when calculating CRC for next time....I tried seeding 0x0000 .....i tried feeding zeros serially...... Ieven tried CRC_init() 

   

The CRC is not correct ....i dont know what to do further.....

[Anonymous]

 I even tried asynchronous Reset even that doesnt work...Can you please help me out in this....

[Anonymous]

 I am trying to attach the project but it is failing ...is there a size limitation.....I will try again