Hi!

I haven't posted to this forum before. I'm quite skilled in several of variants of assembly and I've resently started exploring the source code and various other stuff of the GMECM in my Camaro.

I want to make a program that will be able to change its mode in run-time, so I don't have to swap chips for race/economy/whatnot.. However, to do that, I need to have a memory location mapped to some pin through which I can feed it some way of selecting which mode I want.

Anyone tried this before?

Thanks,
Marin

 

I'm starting my search with this:

http://www.fortunecity.com/rivendell...ics/42_sch.jpg

 

Are you looking for Reference Material on the 68HC11? If so, look at two of the Sticky Posts regarding Source Code and "Adding Functionalility".

Within those two posts, I posted some links to Motorolla for the Reference Manual. It's over 600 pages and has everything you wanted to know about the 68HC11 but were afraid to ask.

 

Thanks, actually I'm pretty comfortable with 68HC11, since I programmed extensively on 65C02 and I am pretty fluent with 68000.

What I want to know is how I can attach "user input" to my ECM. I am planning to modify the code so the PROM holds copies of various tables along with the main tables actually used so I can shuffle between these during driving.

This I think would be a better alternative than using mutliple chip banks or other stuff that could confuse the CPU since for a brief (but CPU noticable) amount of time the memory access becomes corrupt and most people end up encountering the notorious LHM..

So I need some pin whose input is mapped into memory that is unused on my 1992 Camaro RS 305 LO3 TBI ECM. This pin I could then use to select which set of tables I want to use.

If I'm not wrong, there's plenty of space in PROM for extra tables...

 

A proper chip, will allow for those conditions.
The only variable is if your running race gas, and that hardly demands needing a run time change.

Various aftermarket GN chips have enables you can toggle like anti-theft, for anti-theft/valet.

 

Hm, ok, how do you change between features while driving? Do they provide you with a switch? Have you seen any of these? Do you replace the chip with the one they give you or do they have a whole ECM of their own?

I was thinking to make switches so I could toggle between something like a racing setup which would have AFR on the rich side, with changes in timing in higher RPM, maybe some special setup for eventual Nitrous, or the standard economy-friendly setup, then a on-steering-wheel button to force the transmission on my 700R4 not to upshift (ECM controls that, right?), no-cat mode, etc. etc.

To tell you the truth I know a lot more about systems programming than about cars, but for the last two months or so, I've been doing my best to catch up , so if I said something stupid in the last paragraph, attribute it to my amateurish ignorance about cars

 

Your best bet is to spend some time tuning a well developed chip first. This chip should meet all of the criteria you specified. Then move on to using pins to enable 'nitrous','anti-theft','make car run like sh**' modes. You should not have mode called 'race' or 'fuel economy' because that is what your optimal tune should be called.
Have Fun,
J