What's up with 2716 EPROMs?

[Leo Bodnar]

I have re-written some firmware for R6502 and INS8070 CPUs in an old spectrum/network analyser https://www.eevblog.com/forum/index.php?topic=3502.msg46805#msg46805

It all went well up until I tried to program original UV-eraseable EPROMs NEC D2716.

I have a Chinese piece of sh!t programmer called TOP2004 that is supposed to support them but nada! It does not write them, only pretends to:  I have looked at pins on the scope and it does not even pulse the -PGM pin or increments address bus pins.  Works fine with 27C64, 27C256, etc though.

Anyway after a lot of swearing I went online to find a cheap-ish EPROM programmer to be able to flash the 2716 ICs but it looks like a lot of programmers start support from 2732, e.g. http://www.farnell.com/datasheets/72577.pdf

What's so special about 2716s?

So far I have used 27C256 in place of 2716 with a classic hack of putting it into a socket with top 4 pins hanging lose and connected to +5V.  It works a treat but I want to re-flash now cleanly erased 2716 at some point in the future.

Has anybody here ever successfully programmed their 2716s?

[mikeselectricstuff]

These EPROMS are of a vintage where standards varied quite a bit between manufacturers, e.g. Texas ones needed multiple supply rails, and some makes had some quirks.
TBH I'd just stick to the 27C256's as they will probably be more reliable long-term.

[Rufus]

Has anybody here ever successfully programmed their 2716s?

Yes, but not in the last decade. Last time I needed new 2716's it was easier to buy 28C16 EEPROMS which were plug in replacements. They are probably hard to buy new now as well.

I couldn't find a NEC datasheet but they second sourced a lot of Intel parts at the time and the Intel part needs 25v VPP. Some later die shrunk version need 12.7v. Does your programmer give you those options? or choice of manufacturer and specific part numbers?

[Leo Bodnar]

Finally got it to work.

I have downloaded the very oldest programming software I could find on the Internet and it sort of works.  
Apart from the fact that it issues 5ms programming pulse while the device needs 50msec.  Programming it 10 times fixed the floating bits.

The moral of the story is... there is Chinese quality and there is Chinese quality.  
Since there is no other option don't buy the cheapest Chinese stuff but something more expensive then bottom price.

As to the TOP series programmers - run away as fast as you can.  
Even if they are offered for free.

[Leo Bodnar]

Yes, but not in the last decade. Last time I needed new 2716's it was easier to buy 28C16 EEPROMS which were plug in replacements. They are probably hard to buy new now as well.

I couldn't find a NEC datasheet but they second sourced a lot of Intel parts at the time and the Intel part needs 25v VPP. Some later die shrunk version need 12.7v. Does your programmer give you those options? or choice of manufacturer and specific part numbers?

I had 28C16s on order but they won't be here for another week.  They are NOS from China!    Oh, yes baby, NOS - don't make me laugh.  But will do.  This thing is not going to space.
This is one of the first revisions so 25V it is.  They heat up a lot - I guess they consume about 50-100mA when accessed for read.
The programmer could output it, it just the software was complete sh!t and did not even send the correct commands to the hardware.

I guess most programmers shy away from 2716 because they need 30mV@25V and 100mA@5V during programming cycle.  Programming cycle lasts good few minutes.  This puts power requirement at 1.25W of constant power.

Somewhere along the line I want to replace the whole digital section with a single 16 bit uC based PCB that will handle analogue section control and TFT screen output.
I have penciled in PIC24FJ256DA210 for this - it's a great uC with inbuilt USB and VGA hardware, 98K RAM and 256K flash.
I have used it before and it would be perfect for this purpose.

[david77]

  I can sympathise, I've got the TOP2005 programmer sitting here. It is a piece of shite and the software is even worse. Getting the damn thing to work is an adventure every time.

[Neganur]

I have two used MBM27C16 from Fairchild (both 1980) you could have, if needed. I should be able to program them too.

[tinhead]

Leo,

the programming voltage on 2716 sucks, especialy older EPROM models like NEC,
that's why most programmers can't support them.


I can burn NEC D2716D on my top3100, i remember it was working on top2007 too
but only with External power supply (USB powered didn't work proper on older top models).

Typical 25V PGM works, it does work with 21V too for some never chips,
it is always a good idea to burn two, three times with same content.
Additionaly the top software does have (on second tab) settings for delay,
higher delay helps out too for some hard to program ics.
(some NECs 2716 works with 1ms, some need 50ms and 2-3 times overburning...)


As i have tons of older equipment here, i have of course some EPROMS too, starting from 2708 to 512.
So if you need working 2716 EPROMs (or even better 2732) let me know


BTW, top programmer are not that bad, sure software is not the best (well, the new topwin6 is already light years better)
The best model is of course top3100, each pins can be driven (the older or lower models can drive only some pins),

There is an open source software for top programmer too: http://bu3sch.de/cms/index.html

[Leo Bodnar]

Tinhead, Neganur thank you for your offers!  I will see how things work out.  My plan is to move away from 2716 as they are really heavy in power consumption even in read-only normal operation mode.  It's not something you want in an analyser.

I have opened TOP2004 and had a sniff inside.  Hardware idea seems to be a good one.  Xilinx IC at the core, few variable voltage supplies and a lot of transistor switches to drive pins to arbitrary levels.
This is good and probably what a lot of people would want to do if designing their own programmer.  I know I would.

But a lot of TQFP ICs are hand soldered, software is terrible.  New version does not even try to program 2716s for some reason.  Must be a bug introduced at some point as old one at least does 1ms programming cycle.

Thanks for TOP3100 hint.  I don't mind giving a manufacturer a second chance even though my first experience was terrible.

By the way I have also had TOP2004 problems with some 8-pin serial EEPROM - can't remember now.  It won't program.  Luckily I also have ELNEC programmer and it worked a treat then.

[74HC04]

The following link may be of interest regarding the design (and modification) of the TOP series, the TOP2005 being the subject of this article.

http://openschemes.com/2010/04/29/turning-a-top2005-eprom-programmer-into-a-desktop-test-bench/]
[url]http://openschemes.com/2010/04/29/turning-a-top2005-eprom-programmer-into-a-desktop-test-bench/[/url]

Regards

[Leo Bodnar]

I had 28C16s on order but they won't be here for another week.  They are NOS from China!    Oh, yes baby, NOS - don't make me laugh.

I take my words back.  They have arrived and they are pristine virgin unused ICs dated 9607.
I bought them here:  http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190442699493