# Checksum

## SysEx Checksum

I all,

I would like to find a way to get the correct value for the checksum 3e in this example

F0 50 2C 04 00 11 00 10 20 00 00 01 xx xx 00 **SUM** F7

the checksum is the summation between ( ) so the sum of 14 bytes before the SUM starting at 50.

xx xx are 8 bit data

F0 ( 50 2C 04 00 11 00 10 20 00 00 01 00 00 00 ) 3e F7

50 + 2C + 04 + 00 + 11 + 00 + 10 + 20 + 00 + 00 + 01 + 00 + 00 + 00 =. 3E

If I use external 8-bit checksum calculator it works perfectly but I can’t find a way in CTRLR, any idea ?

In CTRLR The Zy calculation seems not to be the right solution because I need to include the 12 bytes before the calculation and if I use y with greater value than 9 the result is always 0.

Regards