Checksum (crc_8)

I’m not sure if it is a bug.

I have a device with rs232

By the description of the manufacturer there are 30 Bytes

a startbyte, 27 data bytes, a crc8 byte and a stopbyte.

When I try the example strings, it works. But when I want let vvvv generate the crc8 Checksum, vvvv does a totally diffrent result.

Is checksum crc8 proper for sure?

Check attached files.

temp_2009.04.07-21.58.28.jpg (210.7 kB)

And the source code for the crc8 used by the manufacturer (attached)

crc source code.jpg (41.9 kB)

And the patch (Version 40beta20)

checksum test.v4p (21.9 kB)

hello, there are 64 possibilities to calculate a crc8 checksum, vvvv uses another. CRC algorithms use a constant value called the ‘polynomial’. this is the value &H8C in your code, the result depends on this constant. vvvv uses &HD1. you could write a small plugin using your code…

without having a look into your patches (wheather is too good, excuse me):

you may want to try the attached module. it works reliable with BSS Soundweb Third Party Protocol.

Checksum (String XOR).zip (5.2 kB)