I did some searching w/o any results. Do I need to ground the last 4 pins on my at29c256 to make it work with my friend's 91 TBI computer? The device offset should be 07000, right? I'm just getting a flashing ses.

thanks,
-Tim

 

I've done this in a 7747 with no trouble, and a '6870 with some issues..
Do a search on '28c64' and you'll see a post where ken73 describes how to do it.
I also recommend reading my recent thread about the chips corrupting, altho this has only happened in the 2 6870's that i have done, never a 7747....

 

Found it, thanks!

 

wait a minute, will that work for an AT29c256?

 

Not directly, youll need to compare pins. Basically you want only the lower 4K, or lower 32,000 kbits to be accessed. Off the top of my head I dont know which pins youd need to ground. Id assume all above address pin A11.

 

There are several threads with that information that I found a few weeks ago when I socketed my 148.

I used the moates adapters, and if I am not mistaken he has the diagrams and some great pictures of it at his site also for some firther reference.

later
Jeremy

 

3.8Transam, I don't need to know how to socket the ecm. Have already socketed it. Guess I'll just try to connect VCC from pin 26 to pin 28, and A12 to ground. If that doesn't work then I'll ground out the last 4 pins. For some reason I can't find out exactly how to do it(via search).

 

All the unused address pins that address larger blocks of mem. then what the binary takes up need to be grounded.

 

so the unused pins + A12, A13 and A14 need grounded? I seen a resistor on the moates adapter, I think.

This is really for my friend Dave. We are trying to get a little more performance though the chip. His car is the red 91 vert that was on HPTV. Right now dave has ran a best of 13.2 . It's a stock 305 TBI with headers, exhaust and a 125 shot of nitrous. The stock T-5 and clutch is holding up quite nice. Not to bad for a heavy *** firebird.

 

That was probably for bin switching. A pull down resistor and switch to ground will provide +5 volts and 0 volts to select the banks of memory. IIRC, there are some good articles on the 'net about how the addressing works. Basically each address block that is controlled by each pin is 2^(the number of the pin). Unfortunatly, the only way to find these is by doing the dreaded and sifting through the results.

 

Why not just buy moates adapter for the tbi ecms to use the flash chips? Is that what you are trying to do?