WTT: HP 85 Assembler ROM 00085-15007

[Michael Fehlhammer]

(02-05-2016 01:10 PM)Paul Berger (Canada) Wrote:  I am guessing that you "Custom PRM-87" has a custom programmed CPLD with a different set of preprogrammed select codes, if that is the case it would make me wonder why the seller does not make that available as an option to current buyers.

You guessed perfectly right, Paul.
Bill Kotaska programmed a custom CPLD, and I made my own SUPERROM ( ROM images are available online, you just need an EPROM programmer and a 27C512 EPROM (512 kBit = 64 kByte) that hosts 8 ROM modules ( 8 KByte each ).

My configuration looks like this:

Contact# ROM Address ROM Name
---------- ------------ --------------------
17 232 (E8 Hex) Advanced Programming
18 240 (F0 Hex) Printer/Plotter
19 177 (B1 Hex) Matrix II
20 56 (38 Hex) SYSEXT
21 231 (E7 Hex) Advanced Programming II
22 176 (B0 Hex) Matrix
23 192 (C0 Hex) Input/Output
24 207 (CF Hex) Extended Mass Storage

Since there is a socket for a second EPROM and two DIP switches for ROM addresses, I can use two more ROMs - Assembler and MIKSAM, for example.
So I need only one PRM-85 occupying just one slot to provide 10 ROMs!
Well, admitted, I counted Matrix I and II as two ROMs, same with Adv.Prog I and II. By the way, I think that Bob is right and there is no additional functionality in these double-ROMs, compared to the HP 85- single-ROM versions.

I did suggest to Bill and John that they should offer my custom CPLD along with a suitable SUPERROM to customers who want to use PRM-85 in their HP 86/87 machines, as would seem natural naming it PRM-87, since this obviously would be a big improvement at practically no additional costs. Obviously they forgot about it. I guess they personally use HP 85 machines only.

My tip for HP 86/87 owners who already got their PRM-85:
Ask Bill if he sells the custom CPLD ( which he made for me ) separately.
I am pretty sure he will, for little money. Since the CPLD is in a socket, it is (relatively) easy to replace. I can provide an image of my SUPERROM.
Then you just have to burn that image into a standard EPROM, or find someone who does that. Should not be that difficult. That's all to be done to get your own PRM-87.
If several HP-87 users ask for this modification, Bill and John certainly will offer a complete PRM-87 in future.

Well, by the way, for a perfect solution you might want to integrate your PRM into a nice housing; then you have to slaughter an HP-IB interface module, for example ( I did that ). Or does anyone here sell HP series 80 module cases? :-)