nAst1: Progress and Concepts Thread

[caffeine]

Interesting..... Makes you wonder how difficult it would be to modify a minimalist open-source C compiler... Of course then the program would have to be translated into C. How different are the assembly instructions used here from, say, x86 instructions?

If this were available in C code I'd be interested in doing some of my own programming.

[robertisaar]

a lot of it looks that way.

supposedly, GM did the main loop and a lot of the minor loops in C with certain sections of code done by hand...

some of the overflow and underflow checking is a dead giveaway.

[caffeine]

Then again, a standard C library probably wouldn't have too much use in this application. Most if any of the functions used would be mathematically related Im assuming.

[caffeine]

Unfortunately, higher level languages usually have the trade off of a bunch of unused code taking up space.

[robertisaar]

oh, durr....

at least the hard part is already done, modifying the patch to have a couple more items to check is cake.

of course, if i knew C/C++ and could use it to compile directly to 6811 assembly, that would almost be the exact string i would need to punch in.... but high level languages = me no comprende.

[caffeine]

That logic, of course also checking clutch pedal status for step 1 and 2 .

[robertisaar]

ah, yeah that would do it too...

guess i'll add that in the to-do list for 1.08 as well...

thinking out loud: logic would go something like this:

TPS threshold for step 1 check
if pass, do RPM threshold check for step 1, else go check step 3
if too high, go do cut

do TPS threshold for step 2 check
if pass, do RPM threshold check for step 2, else go check step 3
if too high, go do cut

step 3 RPM check
...
...



this way, step 3 will ALWAYS be referenced against if not cutting already due to 1/2.

[caffeine]

TPS threshold for step 1 and 2, since I could hit step 2 rev matching for a downshift.

[robertisaar]

sounds like the right circuit.... very few to no vehicles using the PCM driven low coolant light.

TPS threshold sounds like a good idea... only for step 1, or step 2 as well? step 2 is really only intended for WOT w/pedal in anyway, so i'm not sure if it would be of any use. i guess if you were to run above the step 2 cut threshold, drop throttle and then clutch for the shift, it could happen(and not necessarily be wanted) without a TPS threshold on it.

[caffeine]

Shift solenoid B/low coolant light on 90- ECMs. I think anyway.

Also would it be simple to add a TPS threshold to the 1-2step limiters so that I'm not constantly hitting it in daily driving? (Need to get some revs going to engage 1st with the 3.23 gears). Also could be good for doing burnouts at the track without needing a switch to disable the limiter. I.E. not going full throttle until clutch is engaged.

[robertisaar]

wow, i'm easily distracted.... actual code to do the MAP PE threshold only took ~10 minutes to deal with, but there was a good 2 hours of time from start to end that i can't reallt account for....

anyway, know what pin we determined would work well for the reverse solenoid? i can't remember. this could be used for a lot of things actually, i may add in a bunch of mini-patches to allow for different types of values to be compared against. so if someone wanted to run the 3500/3900 VVT function at two discrete settings based on RPM, they could just set the RPM switch point and choose normally on or normally off and they'll be good to go. or always having a fan active below a specific MPH... or a throttle level below which a wastegate is fully open or closed....

lot of possibilities.

anyways, trying to get the AE while PE issue done today too, just working on the t56 solenoid/multi-purpose output.

[robertisaar]

could be tomorrow... i mean, the stuff that needs added in isn't that complex, won't take long to test.

[caffeine]

How long till we see a 1.08 release?

[robertisaar]

moar crazy-old info:

http://lists.diy-efi.org/pipermail/gmecm/2000-April/008689.html

turns out, SOME P4 units got a different processor than the typical P4s... this version has 1024 bytes of RAM instead of 512... i wonder how commonly that it got used with remanned units?

[robertisaar]

well, now i know why my MAF simulator wasn't working...

some of the oldest DIY-EFI archives jusy popped up, came across this string of messages:

http://lists.diy-efi.org/pipermail/gmecm/2000-January/006748.html

culminated here:

http://lists.diy-efi.org/pipermail/gmecm/2000-January/006762.html

the 8706 mentioned is a batch-fire ECM used on the buick 3300s.... internally and externally, it looks identical to a 1227730, i may still have the comparison pics somewhere, but the only real difference between them was the resistor/cap filter for the VATS/MAF circuit changed and i think one IC had a different part number.

anyways, using the values spec'd, the 7730/27/49 MAF/VATS circuit has a 159Hz low-pass filter.... so any signal above that is filtered out. using the 8706 numbers, it has a 27,234Hz low-pass... in reality, i have the table setup for 976-12,240Hz and there is no high-pass filtering on the circuit, so that won't be a problem.

so, to use a high-frequency MAF on a 7727/derivative, you would have to open up the case and change 1 resistor and 1 capacitor... i may take pics to give a good idea of how difficult it would be, but i've resoldered a few pieces on mine already(to add a few useful A/D channels) and i didn't think it was difficult. luckily, the SMT components aren't too tiny on this vintage of PCM.