I just altered a prom eraser to accept a stock memcal. I can erase the prom, PP2 tells me it's erased, move a .bin to the buffer, and fail to write all the data to the stock prom in the memcal.

The prom in the memcal says it's a AD27C256. I selected 27C256 in PP2 because there is no option for AD27C256.

When I "Program Device", it does't write the data properly to the stock prom. It also (of course) won't verify to buffer.

What should I try now?

 

What did the stock memcal come from that you are programming? Does it have a "window" under a sticker? If no window, call it an AT29c256 & start the burn at 4000, select this from right side of screen in "device start" window. If it has a window, call it a 27c128 & start the burn at zero.

 

The memcal came out of a 730 ECM. Probably from a V6 Camaro. I'm using this memcal (and others I have) to test this out before I try to modify the prom in the 5.7 TPI memcal I have.

I was just able to program the prom with PP2 setting of 27c256 starting at 4000 in the buffer. However, it did not verify to buffer after programming. These proms DO have a window under the sticker. I tried 27c128 at zero buffer and it didn't work. Are you sure you meant 27c128 and not 27c256 as is shown on the prom in the memcal? I guess I don't understand the logic of starting at zero or at 4000. Any help there?

I appreciate the help so far.

 

First what size bin file are you using?

Most are 16K or 32K

A XXX128 eprom has 16K of data. A XXX256 eprom has 32K of data.

Burning a 16K bin to a 32K capacity eprom means either doubling (stacking) the 16K file to create a 32K bin, or starting to burn at $4000 in the chip and use the 16K bin. Just putting a 16K bin at $0000 in a 32K eprom will cause the ECM to trigger the SES.

Do yourself a favor and get a couple AT29C256 EEproms from Craig Moates. These are "flash" ei electronically erasable eproms which do not need UV to be erased. Just program directly over the old data. Saves time and, really is a better chip. BW

 

I must be using a 32K bin. Up until now I've been using Craig Moates' adapter and flashable proms. I have no problems with the flashable proms. I didn't want this post to turn into a post about flashable proms though. I don't understand the troubles I'm having with the stock prom in the stock memcal. Everything erases fine, but I must not have the correct chip type selected or something. Any other ideas?

Since the stock prom shows AD27C256, the bin is 32K, I'm assuming I should select 27C256 (since there is no AD27C256 in PP2), and simply click "Program Device" to move the bin to the stock prom in the stock memcal. Something doesn't jive with this though. The prom is programmed, but does not verify to buffer.

 

I'm not sure, but I don't think a 7730 ecm had a 32k bin. I have a program that should tell me the bin size if I have the id code. If you give me the code, I may be able to tell you the size of that bin. I once found a link poss (gmecm) that gives you eprom types & bin sizes for various ecms, I will try to find that & send it along.

 

Forget what i last said, It's early in the morning. All I can find shows the 7730 ecm uses a 32k bin with a 27c256 in some ecm's & a 16k bin in other ecm's with a 27c128 chip (mostly 2.0l eng). Try this site for reference www.cruzers.com/~ludis/idxref.html

 

The f-body '730 3.1l V6 bin's use a '256kb EPROM.

RBob.

 

Awesome info guys, I'm still trying. Waiting for the prom to erase right now to try again.

 

Turned out to be a bad prom in the memcal. Actually I had two bad proms. Anyway, it all works great now.

Thanks Guys!

 

I just recently came across this same problem. I am doing some work on an AXCR bin. I had to put the memcal in the burner three times for it to erase completely, which was rather strange. I tried to program the buffer (I'm using the pocket programmer), and it went partly through the burn, and stopped. It said "device could not be programmed" or something similar. After that, it was still blank though. I tried it again, and it wrote something this time, but still failed at the same hex address. I placed it in the eraser again, pulled it out, and verified it was blank. Now I am trying to program it again, but it fails at the first hex address.

The eprom has AD27C256 written on it, just like the previous posts. S10Wildside, how did you conclude that the eprom was bad in your case. I am stumped with this right now, and unsure of what is going on exactly. This was recently pulled out of a running car.

 

I haven't been able to erase & reprogram stock chips with much success. I don't know why. I also have a PP2 and a UV eraser. Still get the same message you get. I just gave up, who cares about those rotten oe chips, I just went to Craig Moates and got some adapters so I can use much better chips with my memcals. You will be able to reprogram the Atmel 29c256 chips over & over without any issues, the PP2 will erase & reprogram in one step, no UV eraser needed. Also I just got some SST 27SF512 chips also, they can store mega data. Do yourself a favor and get an adapter & some newer flash chips, you will love them.

 

I personally use one of Craigs G1 adapters with a zif socket and Atmel 29C256 chips on my car, so I'm familiar with that. I have done quite a large amount of work on stock memcals via this same method and never had this problem before. This isn't something I'm doing for my own use, this is for someone else, and it needs to be done via the factory chip. I just need to figure out whats going on exactly, and if the chip is bad.

 

Heh, that sounds familiar.

I’ve found some OTP proms in a couple of ECM’s but most have a normal eproms and I’ve been able to read them and erase them but I’ve never successfully reprogrammed on…

 

Can you desolder the oe chip & replace with AT29c256. I've done this before, works great.

 

I guess I could, but my soldering pen is way too thick for that. Its a cheap radio shack pen, and I don't think the tip can be changed.

 

I just used a pocket screwdriver to pry up on the old chip while I heated the pins, my tip was also rather large, it didn't matter much that I damaged the chip since I was tossing it anyways, then I was able to clean sockets after chip was out. Try it on an old chip first, its not too bad.

 

I have 3 laptops i use with my eprom programmer. All 3 work fine for 29c256's etc, but only one will work with the stock chips in the memcals.. dunno why??