I have been working my way through the '97 Camaro code and making good progress. It is a bit daunting to look at how much still remains, but I keep plugging away at it.

It has been suggested to me that the Optispark is the heart of the system and that I won't make much progress without a good understanding of it. I thought it would be easy to simulate the physical unit for use on the bench and I set out make one. I had an old board that we used way back when 68HC11 was newish. I ran into any number of troubles with this idea. I will keep the whining to a minimum BUT first the reset chip had a watchdog that needed s/w service. Hard to do when you want to use bootstrap mode. This particular board had three interconnected 68hc11 chips all running in single chip mode. The interaction between all this caused hours of delight OK OK whine mode off

I have completed the program and will describe the result along with what assumptions I have made. The first assumption I made is that the windows in the optical disk represent logic 1. That is when the light shines through the output is set. I have not yet connected it to my bench ECM. This is the first thing I need to confirm.

Second, from pictures of the optical disk I see that the "High resolution" will transition low to high in the center of the "Low resolution". This is the relationship I set up on my Opti-Simulator.

Here are the waveforms...
IMG_1662.jpg
This screen shot is the low resolution and high resolution. You can't make out the timing of the high because there are way too many pulses

IMG_1665.jpg
This shot is the low and high resoluton for one of four cylinders 1, 4, 6, 7

IMG_1655.jpg
This shot is of cyl 8

IMG_1666.jpg
This shot is of cyl 3

IMG_1667.jpg
This shot is of cyl 5

IMG_1668.jpg
This shot is of cyl 2

If you have any interest in the code, pm me.

I needed and wrote a console app to convert S-records to the binary that bootstrap mode needs (leading sync for auto baud) I have that also if there is any interest.

I look forward to following this up with details of the ECM code it drives.

If there are any errors above, please let me know!

-Tom










The software I wrote is crude. The maximum rate could be increased from 4000 with a little code clean up. This is intended to give me a good start. I will post some results