Nathan Plemons

I have in one of my computers right now a Needhams PB10 chip programmer / reader. It reads just fine, in that it will read my Ed Wright 27C256 chip perfectly. However the chips I have to write to are 29C256's. They are very nice in that they are flashable and so you don't have to have a UV eraser, and oh yeah I have 2 of them ;)

The problem is that the PB 10 does not really know how to communicate with the 29C256. It will read one of these chips as a 27C256 set to 5 volts, but it cannot write to it. Here's the deal, this chip programmer is actually an internal ISA card that has a ribbon cable attached to a ZIF socket. The software that came with it has the program for the EMP 20, the external programmer made by this company at the same time. It knows how to talk to a 29C256, but of course it can't talk to my internal programmer card.

I know, a pocket programmer will solve all of these problems, but this was free so I am going to do everything I can to try and use it. I can just use 27C256 chips I suppose but I don't have any spares, nor do I have the UV eraser. I might find a few at work, and I we do have a UV eraser, but I was really hoping to be able to use these flash chips.

Any ideas?

-=Jeff=-

What voltage is needed to program and erase the 29C256 PROMS? I don't know off the top of my head, but I would think if you have an external power source for the PROM it would work..

EDIT= I have the PB-10 as well, but never gave it much thought to get it to work.



[Modified by -=Jeff=-, 7:56 AM 10/23/2002]

Nathan Plemons

It uses 5 volts but I don't think it's a matter of voltage but rather the writing algorithm.

If you want to write to a 27C256 it uses the Algorithm "Intelligent 1ms 3X"
The other software which can write to the 29C256 wants to use the "64 Byte Page (10ms)" algorithm

In fact I went out to the Atmel website and downloaded the specs on my chips, it claims that they do not even have to be erased before you can write to them, and that just writing to them again effectively erases what was already there. I would prefer to erase them first of course just to verify but I would be willing to try just writing to it. Unfortunately it doesn't work if I try to write to it as a 27C256 set for 5 volts.

I guess I may just use 27C256 chips. We have a UV eraser at work and such. I just really wanted to be able to use the flash ones.

-=Jeff=-

Yep,

After I posted I looked at the Data sheets for both..

Oh well one of these days I will break down and buy a EEPROM programmer