Nissan ECU Tuning

bemis · Joined: 14 Nov 2006 Posts: 17

Yeah, this is a stretch, since they are obsolete, but I'm looking for them.

Or maybe, a source?

Calum · Joined: 11 Feb 2004 Posts: 226

Good luck.

How much room do you have physically around the socket? Making an adapter for a 28-pin chip wouldn't be very hard, I bet someone makes something off the shelf.

bemis · Joined: 14 Nov 2006 Posts: 17

I've thought of making an adapter if I can't find anything.

I can go out to the junkyards and pull almost every EPROM out of 80's GM ECMs. They are 2732 EPROMs, but then sometimes they only have one programming cycle and can't be erased with a UV light.

Calum · Joined: 11 Feb 2004 Posts: 226

Yea, I guess it depends on what you need it for. I hate using UV erasers, so I would just knock out an adapter board. I've switched to using 27SF512s and a moates.net burn1 for just virtually everthing these days that needs a ROM chip. Its a knock-out combination: fast, works everytime, and cheap (I buy the 27SF512s in quantity 500). If its for a car, you can do nifty tricks with a larger sized rom and an adapter board- stick a flip-flop on there and you can do transparent bin switching. Add a little mcu (I like using PIC12F629 or 675) and you've got a cheesy (but very capable) nitrous controller. Fun stuff. Razz

Calum · Joined: 11 Feb 2004 Posts: 226

If your still looking for these Jameco has them in stock. Just noticed the other day.

http://www.jameco.com/webapp/wcs/stores/servlet/KeywordSearchResultView?langId=-1&storeId=10001&catalogId=10001&searchType=k&searchValue=27c32&categoryId=105040&rscount=3

bemis · Joined: 14 Nov 2006 Posts: 17

I've heard that they might have some.

I have had a 1 in 4 success rate of erasing and reprograming the 2432 chips that I have pulled from the junkyards. Mostly because my cheap Willem programmer can't make enough current for the 25V write voltage. And, Delco switched back and forth between 2732 and TMS2532 chips, which have different Vpp, ~OE, and ~CS locations.

So, if I can't reprogram the orignals, then my next step is to build an adapter to fit SST27SF512 EEPROMS on to the PC board. According to the pinouts between the two chips, all I need to do is place a 28DIP socket into the 24DIP slot on the PC board. To make it fit, I cut pins 1(A15), 2(A12), 27(A14), 26(A13) on the 28DIP. Then I route hole 24(Vcc) to pin 28 on the 28DIP with a small wire. I'm not yet sure if I need to ground pins 1, 2, 27, and 26 so they are not floating.

Calum · Joined: 11 Feb 2004 Posts: 226

Don't leave CMOS inputs floating. Pull them up or down.

bemis · Joined: 14 Nov 2006 Posts: 17

Which ever way I do pull them, I should note that in my programming too.

Pulled high, write software at end of chip.

Pulled low, write software at front of chip.

So, I guess this means that Nissan typically pulls their EPROMs high, since, without making hardware modifications, I have to write my software at the end of the chips.