Calculating 8 bit checksum from a series of bytes?

[tcbcats]

I am doing some serial communication and need to calculate a 8 bit (one byte) checksum by adding up a series of 10 bytes.
I have been able to do it but when the checksum value goes over 255 is keeps counting up and ends up in a 16 bit value.
I need the 8 bit value to roll over from FF and keep the checksum result in a 8 bit value that just keeps rolling over to 00 when he count reaches FF.
I there a simple way to do this?

[dunbarx]

Hi,

Can you (pseudo)

Code: Select all

put checkSumValue mod 255 into checkSumValue

This will roll over, where 254 = 254, 255 = 0 and 256 = 1.

Craig

[tcbcats]

Thanks it worked... had to set 255 to 256 in order the keep the correct count sequence.