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EEPROM availability 2532 & 2732 replacements.

H

Hugo Holden

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Is there a readily available EEprom (electrically erasable ROM) that is pin pin compatible with either the 2532 or the 2732. Ideally there would be a different type that could directly replace each, and also be readily programmable in common programmers like the GQ-4x.

I have not been able to spot any obvious candidates yet. It would be good to have a type that replaced the 2716 too.
 
The 28C16 can directly replace the 2716. The 2732 is not a size currently manufactured in any form. I would think an interposer board would be the way to address both 2532 and 2732 using a 28C64. You could also have some jumpers on it to select one of two images as well as pinout changes between the 25xx and 27xx.
 
Amardeep-AC9MF said:
The 28C16 can directly replace the 2716. The 2732 is not a size currently manufactured in any form. I would think an interposer board would be the way to address both 2532 and 2732 using a 28C64. You could also have some jumpers on it to select one of two images as well as pinout changes between the 25xx and 27xx.
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Thank you for those suggestions. Interesting that the data retention on the 28C16 is suggested at 200 years !

I wonder if anybody has already made a suitable adapter board for the 28C64.

Also I had wondered about an FRAM replacement like the FM16w08 on an adapter board with switches (I have a good number of these left over from a project using them to replace the DS1225 in Tek 2465B scopes). The file could be duplicated 4 times and selected by a small hex pcb switch. The data retention in these is 150 years.
 
Hugo Holden said:
Thank you for those suggestions. Interesting that the data retention on the 28C16 is suggested at 200 years !

I wonder if anybody has already made a suitable adapter board for the 28C64.

Also I had wondered about an FRAM replacement like the FM16w08 on an adapter board with switches (I have a good number of these left over from a project using them to replace the DS1225 in Tek 2465B scopes). The file could be duplicated 4 times and selected by a small hex pcb switch. The data retention in these is 150 years.
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Yes the FRAMs are very nice and the durability is long enough in the later generations as to be virtually limitless at least for hobbyist use. I think there may already be adapters like for the xx32 parts. I'll do a little scrounging around to see what I can turn up.
 
I know I am not answering your question but I had a GQ-4X and I ended up getting another programmer. The ME2700 does these chips. I later upgraded to a EEtools Topmax II for USB support. If you are going to do a lot with these types of chips, it might be worth looking at an alternative programmer for the older chips that the GQ-4x doesn't support. Those adapters add up after a while.
 
It makes me wonder why manufacturers of EEproms didn't make an equivalent replacement for the 2732 and 2532 UV eproms ?

I think Rockwell made mask proms that did, the 2332A and 2332B to suit the two pinouts.
 
Chuck(G) said:
I've heard rumors of an AT28C32, but have never seen one and datasheets seem to be non-existent.
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Some manufacturers would produce a data sheet before the part came off the production line.

One of the better examples I know of this is the Cy9C6264 Magneto-Resistive MRAM.

Here is a remark I wrote about this once:

Another type of non volatile ram is Magneto-Resistive, or Mrams. Cypress were developing this technology around 2004 to 2005. They produced a preliminary data sheet on a CY9C6264 and the pdf datasheet for this item circulated the internet, often taken up by the search engines “Stocking Parts Supply Companies” some of whom claim to actually have it in stock. It was a byte-wide 8k x 8 non volatile memory IC in a SOIC 28 package. However it appears they were never mass produced or commercially shipped to suppliers at all because Cypress sold off their Mram technology.

I came to call this number the "probe" because it is a "tool" you can use to figure out if some company is a genuine parts stocker or not. Because the part doesn't physically exist. So if somebody claims to have this part in their inventory or stock, you know they are not a stocking supplier, but merely a re-seller who waits for some sucker to place an order, they try to source it elsewhere.
 
In a sense, I can see why the EEPROM version of the 2732 was never produced. The period where 32Kb EPROMs held sway was fraught with incompatibilities and was fairly brief (one reason was the move to +5V only units). It didn't take long to move to the 28 pin 64Kb devices, which were enormously popular. The 24 pin 64Kb EPROMs got left in the dust as well.
 
Chuck(G) said:
In a sense, I can see why the EEPROM version of the 2732 was never produced. The period where 32Kb EPROMs held sway was fraught with incompatibilities and was fairly brief (one reason was the move to +5V only units). It didn't take long to move to the 28 pin 64Kb devices, which were enormously popular. The 24 pin 64Kb EPROMs got left in the dust as well.
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From what I have seen the voltage transition to 5V happened between the 2708 and the 2716. I think the 2708 was a lot like the MM5204 and needed the multi voltage. The S-100 Cromemco 8k Bytesaver II board can program the 2708 (easily with Martin Eberhard's software) and he also made the ME5204 programmer too. I programmed some of these for my SOL-20.

Recently when I added an extra ROM to my AIM 65, I chose the 2716, simply because of the "just 5v" even though only 512 bytes was substituted in as ROM and it was dead easy to program in my GQ-4x programmer. (I also have a BP 1400 programmer too, what a masterpiece that machine is)

By far and away the best quality and flawless ROMs I have been able to find lately are coming out of Bulgaria and many are ex mil spec stock and or genuine Japanese or TI parts.
 
Well, the TMS2716 still required a substrate bias supply Datasheet and so was compatible with the 2708. The TMS2516 was +5V Vcc only, but was incompatible pinout-wise with the 2716. The nonsense continued WRT pinout differences between the TMS2732 and TMS2532. Things didn't really get set aright until the 2764 in a 28 pin package.
 
Chuck(G) said:
Well, the TMS2716 still required a substrate bias supply Datasheet and so was compatible with the 2708. The TMS2516 was +5V Vcc only, but was incompatible pinout-wise with the 2716. The nonsense continued WRT pinout differences between the TMS2732 and TMS2532. Things didn't really get set aright until the 2764 in a 28 pin package.
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That is interesting. I did not know there was an incompatible 2716 part, in that a TMS 2716 was different to most other 2716's I have seen, where pin 21 Vpp is normally tied to +5 V in read mode , but on a TMS2716 it is VBB and has to be tied to -5V, that is a real trap.

I assume the TMS2716 won't work with its VBB pin tied to +5V ?

The type I have mainly used are "2716C", which appear to behave normally with pin 21 Vpp tied to + 5V in read mode.
 
No, like he 2708, Vbb has to be -5 or thereabouts. As mentioned, the deal with 2716 and 2732 was a bit of a mess. For example, the NS MM2716 needs only Vcc. Note that JEDEC JESD21C makes a special exemption for the 4Kx8 EPROM {"type B").
 
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Chuck(G) said:
No, like he 2708, Vbb has to be -5 or thereabouts. As mentioned, the deal with 2716 and 2732 was a bit of a mess. For example, the NS MM2716 needs only Vcc. Note that JEDEC JESD21C makes a special exemption for the 4Kx8 EPROM {"type B").
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The only other 2716 I have used aside from the 2716c is the Fujitsu MBM2716 and the SGS Thomson M2716 and these don't need the -5V.

Is there any other brand of 2716 that you know of that needs the -5V like the TMS2716 ? (So I can avoid them)
 
The TI one is the one I recall from "back in the day". I don't know if there were others. The word on the street was to avoid the TI TMS2716.
 
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