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The both the Ace ROM's are in fact 2532 EPROMs. They can store 4096 x 8, - 32,768 bits, ultraviolet-light-erasable, and programmable with the correct EPROM burner. They come in 24 pin DIP type package like the image below.
You can spot the manufacturing code on these chips as "8305", made in 1983 (83) in week five of that year (05).
The 2532 EPROMs can operate from a single +5V supply (in the read mode). No pull up resistor are required, static operation, no clocks or refresh. All inputs / outputs to the chip can be driven be 74 series TTL circuits, of which the Ace is built from. A full data sheet on the 2532 EPROMs click here
For an image of the Aces ROM see the ROM's download page.
The 2532 EPROMS are now very hard to find, also the modern EPROM readers/ burners might not support them which makes building as Ace seem difficult, But we have a simple effective solution with the
EB ROMboard thanks to Edwin.
2532 EPROM Important Information.
The 25xx series is almost exclusively Texas Instrument TMS EPROMs.
As the story goes, TI developed the TMS-2716 (2K EPROM), but like the 2708 before it, it needed three voltages sources to program/use them . This was more complicated and therefore more expensive.
At roughly the same time, Intel also launched "their" 2716 chip which was different than the TMS-2716 in that it only needed a single voltage to program (25v) and a 5V to operate. The Intel pin out was also a bit different than the TMS pin out.
Similar to the Beta vs VHS battle, only one could survive and Intel proved to be the more popular, and thus, most other manufacturers produced Intel-like 2716.
Bowing to pressure, TI also produced an Intel-like chip but could not call it 2716 since they already had a 2716. So they identified it as the TMS-2516. And thus was born the 25xx series.
Unfortunately, the story does not end there...
After the 2K chips came the 4K chips (xx32) Intel simply used the same pin out as it's 2716 and added an extra addressing pin, thus the 2732. TI again decided to use a different pin out and to differentiate itself from the Intel 2732, it named it the TMS-2532, these are used in the Jupiter Ace)
So 2532 is NOT compatible with 2732
Virtually all 2532 you'll find are TI chips. Only very few manufacturers other than TI made 2532, everyone again followed Intel's lead to create the 2732.
As far as I know, there is no TI 2732. (...but TI stopped the madness by adopting the Intel standard for all chips starting with the TI 2764 )
Also, unlike the TMS-2716, the TMS-2532 WAS pretty popular
and used in several applications (...notably arcade games. )
The 2732 and 2532 are NOT programmed the same way and are not interchangeable without some board modifications. Virtually ALL EPROM burners will do 2732, but some of the cheaper ones will not do 2532.
As for programming voltages, all early EPROMs need 25V. Chips ending with an "A" (like 2732A or TMS-2532A ) need 21V. The 12.5V is only used in "newer" EPROMs (circa late 80's), typically CMOS chips, like 27c010, etc... (a good EPROM burner with decent software will know which parameters to use for each chip )