HP75 EPROM Buring


The hp75 utilizes a standard TI smj27c256 32K eprom. Burning to this eprom should be fairly straight-forward.

Does anyone have any information past this? How does one place hp75 files on the eprom? Do you need the hp75 plug-in rom simulator (PMS)?




I don't think you need the ROM Emulator---it was for testing that what you were going to burn would actually run from ROM. As a secondary intent, I think it was assumed that some users would send the ROM Emulator to a service bureau to have actual ROMs made for them.

I had the ROM Emulator but used it just to increase the data space available for my programs. By putting my programs in the ROM Emulator, I could have almost the whole 24k of RAM available for data. (I don't remember exactly how much of the 24k was available.) The ROM Emulator had two 8k "banks" if I remember correctly.



From the manual, it seems like HP would have also allowed customer send them the rom image on either mag cards, tape, or diskette. The reason I think this is because the PMS manual directs the user to request a ROM i.d. from HP before sending them anything. Then you actually have to re-build your rom using the ROM i.d. HP assigns.

The rom image can be obtained with the command "copy 'all:romX' to 'filename'". This results in a file with a "rom" extention.

Incidentally, the contents of ANY rom can be copied in this manner as long as you have the PMS LEX file on your system. I've copied the contents of my i/o rom in this manner. It consists of 3, 8K lex files which can't be copied any other way (at least not in a straight-forward way).

The trouble is that this command results in a ROM file, not a LEX file. So in order to burn this to an eprom, one would have to somehow convert the ROM file back into its constiuent files.

I'll bet HP had a nice setup on a larger computer that would read in the ROM file, process it, and burn it to an eprom.

Maybe for kicks I could call hp and ask them for a ROM i.d. # for my PMS and where I should send the image to for processing!

BTW, do you still have your PMS? Would you like to sell it? If I had two, then I would have a total of 32K in rom space which would allow me to copy complete roms (like i/o or visicalc) and run them on 2 PMS's (my wife gets a kick out of that acronym).



My PMS is long gone! I sold everything HP75C related in 1986.


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