GM 2.8L V6 ALDL

[Scot Sealander]

"Shawn R. Lin" wrote:

> Maybe the checksum calculated by Carbytes 2.0 is wrong, and that's the
> problem?

Sounds like it.

 
> When I tried sending $F0,$58,$01, it automatically calculated the
> checksum as $B9.

Nope.  Should be $B7.  No wonder it ignored the request.


> If I try sending $F0,$58,$01,$CS, it changes the string to
> $F0,$57,$01,$00,$B8.

Whoops, that should be F0 58 01 B7.  The addition of all those bytes
should add up to zero.  The "CS" stood for Check Sum.


> What's the formula for manually computing checksums?

The last byte sent is the 2's complement of the sum of all the previous
bytes.  That is, if you add all the bytes in the data stream in byte
format,
and ignore carrys, the result should be zero.

Scot Sealander
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