(Forgive all the synonyms? Trying to make this search-engine-friendly)
I struggled to find anything online about using the checksums / CRC built into the software in the Dallas/ Dalsemi/ Maxim API/ SDK for their marvelous 1-Wire/ MicroLan.
Ended up writing my own "answer", which is couched in Lazarus terms...
http://sheepdogguides.com/dst1b.htm