Is there is an EPROM programming algorithm that works for nearly all EPROMs?

I have a Needham's PB-10 programmer. It cost something like $100 or $150 new, and plugs into a PC's ISA bus (which disappeared from new PCs many years ago), so I have it in an older computer I have my DOS stuff on. The computer is a replacement for an earlier one whose HD controller went out, and it wasn't easy to get the not-as-old computer to even recognize the programmer. I haven't actually tried programming an EPROM yet on this computer, but it looks like it'll work now. Unfortunately Needham's Electronics went out of business several years ago.

I seldom need to program EPROMs anymore, but I want to keep the capability, and I'm thinking it might be good to get it away from being dependent on PCs. It would be easy to make a programmer that my home-made workbench computer could control, but it seems that EPROM manufacturers kept the programming algorithms kind of secret to protect the programmer manufacturers. Since the need is seldom now, I probably don't need the super-fast algorithms, although the old, original 50ms per byte would be a killer if I had to do a 1Mx8. (14 hours anyone?)

The PB-10 seems to only have a handful of algorithms, and as I was reading the manual again, it started looking like you could probably do all EPROMs the same way: use the specified programming voltage (higher voltages apparently allow faster programming but require greater care to avoid damaging the EPROM), then for each byte, give it a 100µs pulse, check, do again as necessary until you read back the right data, then take the total number of pulses and do twice that number again for the one location before moving on to the next.

Is this a valid method? Does anyone have better info? It appears that EEPROMs are neither as fast or as dense as UV EPROMs, so I would be more interested in the latter.

http://wiki.xtronics.com/index.php/How_ ... algorithms

And also:
http://www.atmel.com/Images/doc0578.pdf

"Quick" algorithm (i.e. the 100us one you described) should work fine on all of the EPROMS (well... maybe excluding the old 24 pin ones like 2716 or 32, never tried this).
It's been about 10 years since I used professional programmers at work (DataIO's All-xx, Advantech's LabTool) - I do not remember any problems with the "quick" algorithm other than a bad chip.

_________________
Practice safe HEX !

Excellent info, especially in the Atmel ap. note. I didn't know about the bits sometimes getting slowly erased by subsequent bits' programming.

I was hoping not to have to have Vcc at anything other than 5V, so maybe some software experimentation is in order. My home-made PIC programmer can set Vcc to any voltage from 2V to 6V, but it's a lot less circuitry to convert voltages since it's serial and there's only the one clock line and one data line. A big EPROM might have 30 lines to convert, and the 8 data lines have to convert in both directions. Edit: I guess the address and control lines wouldn't need any conversion because 5V (or even somewhat less) is still a solid logic "1" with a 6.5V Vcc, and the data lines could easily be made to protect the 5V workbench computer's inputs from excessive voltages by using low-resistance-value resistors and a diode on each line to a regulated 4.25V or something like that.

When I was programming 8Kx8 EPROMs 27c64 for one of our products years ago with the Needham's programmer using the quick-pulse algorithm, they went almost as fast as you could get the EPROM into the socket and back out; so there was no use in having a gang programmer for EPROMs that small with that algorithm. It wouldn't have saved any time. We never had any problems with them, but maybe the larger EPROMs like 1Mx8 (27c080?) are more susceptible to erasure by subsequent bit programming.

I'm still open to more info any anyone has any.

I just bought a Bytek standalone programmer, eBay item number 270921704048 for $50 + shipping. I almost didn't want to pay that much, but it prevents having to make my own. I did get my Needhams' one in the older PC working, but I would still like to get more independent of the PCs. This Bytek has an RS-232 connector on the back, and any computer with RS-232 can feed the Intel Hex data over this interface. I did this with a similar Bytek one (the Bytek Writer) in the 1980's with even my hand-held HP-41 calculator/computer, and later the HP-71.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources