pcmhacking.net

I dont know if this is of any interest, I found this article that descibes how the knock detection and ESC works in an ECU.
I would assume that it would be similar for our setup's.

Other tech documents by the same author at http://www.turbotweak.com/

whos there? lol, thanks for posting.

Nice doc, had a quick skim and looks mostly relevant to how it works here - certainly how the retard is calculated, the counters etc. The fault reporting is a little different though - the knock sensors have a resistor in them and the ECU looks for a voltage thats under 5v but neither a short to ground or open (in 12P its 10 counts min and 220 counts max, while grounded would be 0 and open 255).