CRC Check for Dellas DS1973 needed

Does somebody have a example code of how to work with

CRC-check in DS1973 from dallas?

I'm talking about the CRC between the write, read and copyscratschpad commando's

I'm already know how to read the CRC form teh button self, but not how to implement the CRC for the datat i write to the scratchpad.

http://www.picbasic.co.uk/forum/arch...hp/t-1672.html

thank you very much