Information out there regarding the use of MS1 with a Renix 44-2-2 wheel is not correct.
The Renix tooth pattern is odd since it has 2 * 2 missing holes every rotation. So, in order to get MS1 to use the pattern correctly it is assumed the number of base tooth put in the wheel decoder needs to be divided as well.
Having set-up the wheel decoder as suggested by most people, i ran into the following problems.
025 wheel decoder > Runs to about 2800rpm
024s9 wheel decoder > Runs to about 5500rpm
Tooth logger shows an erratic pattern. Scoping the IRQ trigger led and input signal shows the cpu is rejecting triggers. Why?
Main problem : Base tooth count. Everyone assumes it needs to be 22. WRONG.
For the wheel decoder to work correctly the base tooth count must relate to the actual frequency the toothed wheel is generating in relation to engine RPM. 44 in case of a renix wheel. I think/guess the older routine can rev a bit higher is due different (more forgiving) IRQ noise rejection.
Having set the base tooth count to 44 eliminated all the problems.
Try it on the stim to see for yourself
