.HEX CHECKSUM

jamie_658 · Guest

Hi,

I am using the CCS Compiler with MPLAB IDE to create a .hex file to email to a vendor for programming PIC16F676s. When I email the .hex file, should I be creating a checksum for the file to be sent in the email? If so, what utility is available to create the checksum? Is there a real risk in not sending a checksum with the email? Question

Thanks,
Jamie

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You can use MPLAB to find the checksum. This thread has instructions:
http://www.ccsinfo.com/forum/viewtopic.php?t=33541

Zip up the HEX and send it as an attachment. If you send it as a zip
file, there is little chance of it being corrupted. If it is corrupted, then
when they try to unzip it, they will get an error message from Winzip.

Tell them the checksum value for the HEX file in the text of the email.

crystal_lattice · Joined: 13 Jun 2006 Posts: 164

A very common method of doing this is using the MD5 Hash. Search the net for a utility to encode the MD5 hash based on input file. Then send your file, utility, and hash to the vendor, they can recalculate the hash and compare results.

Regards

Wayne_ · Joined: 10 Oct 2007 Posts: 681

The hex file should have a built in checksum.

The only reason you would want to do what you are doing is if you are encrypting the file or you have a securtiy issue where the file may be intercepted and a different file passed on.

If you are only worried about corruption during transfer then the built in check sum should cover that.
When the programmer loads the HEX file it will check the checksum to see if there are any errors.

The HEX format actually has a checksum for each line as well as a total checksum.