I am designing an eprom emulator now, but with a twist. I am designing it with two EEPROM chips. That way, it can be powered down and back up without it losing its brains. Also, it will be able to be programmed on the fly simply by flipping back and forth between the two EEPROMs. That is, while the car is running from one of the EEPROMs, the other can programmed. You can then switch back without having to turn off the car. I will have it switch between memory accesses so the ECU won't know the difference. I'll also have to do a PC side app to run it.

I have some questions though if some of you experienced engine tuners could help me out.

First, is this something that others would be interested in? Cost would probably be in the $30 range I think (digi-key parts) or less if a volume build were done. I am asking because if others are interested, prices (especially NRE for the circuit board) can be amortized or otherwise reduced.

Second, what size should the EEPROMs be? I am using a 1227747, and so I only need 4KB of space. What do the newer ECUs use (including Ford EEC-IV)? Would a 32KX8 be big enough?

Third, would people prefer USB or serial interface?

I hope to get schematics done in a week or two, and then get board built and start testing.

Any comments are welcome.

John.

Oh yeah, does anyone know a good way to attach to the EPROM socket on the '747 without having to remove the board and solder in a regular socket?

It's not entirely new in terms of concept, but I'd love to see it reduced to practice!
https://www.thirdgen.org/techbb2/sho...hreadid=107066

make it big enough for 512k chips thatll be awesome. !

I hadn't seen that thread Craig, thanks. I didn't think it was likely to be a new idea, but it seemed like a good one. Once you get the car running pretty well, and just need to tweak a few locations in tables it should work. You probably wouldn't want to download a patch while the engine was running though. I thought it would be great to use it during a dyno run. You could literally tweak each MAP/RPM setting for instance if you had sophisticated enough software.

512K device? Than means 64KX8, right? I was hoping to get by with 32KX8 because the microcontroller I want to use has a 16 bit address bus, but I can bank switch pretty easily.

I wouldn't count on being able to swap the whole .bin file fast enough to not have the ecm crash during the swap.

This whole on the Fly Tuning is iver the top in my opinion anyway.

You have to stop to take notes anyway, so what's the big deal with refiring the engine?.

A 512 emulator would be much more worth while in my book.

Swapping back and forth is easy, that's why you have two separate eeprom chips (could use flash memory too). It only takes about 5 ns to switch between banks. So, the host PC just has to program one bank, switch the ecm over to the other, and then program the second bank. Pretty simple. I'll look at 512K (64KX8) parts. What ECM uses the 512K parts?

Some of the 94/5 trucks & stuff like that.

craig did you get the EEC adapter to run on smaller then 512k chips ?thats my interest.

That still might be enough time to crash the ecm depending on where it's reading.

If I'm not mistaken all the PCMs.

might be a way to replace the flash in the OBDII stuff, and then not have to work around the security, but don't quote me on that.

Having a handy to use emulator for 512s might get more guys into do 4LE8 swaps into the 3rd gens.....
Personally, I'd much rather have a PCM controlled 4L8E then any other tranny.

agreed art carr has something now that truns it into a six speed or something crazy like that. 4l80e is a nice unit. has anybody hacked the deseil controllers yet ?