HP82143 Processor details

[blackjetrock]

(06-02-2023 09:38 PM)brouhaha Wrote:  The processor in the printer is a mask-programmed MK3870 microcontroller (Fairchild F8 architecture) with 1KiB of ROM and 64 bytes of RAM.

I don't think you actually need to know anything about the 3470, which is good because AFAIK no one has dumped the internal masked ROM yet, and we don't have any internal HP doc such as an ERS for that firmware.

That is interesting information. If I can get hold of a broken printer I could have a go at de-capping the IC and getting a die shot. If the ROM data is visible then knowing the processor type would mean a ROM dump could be extracted. I just need to find an unfixable printer...

Quote:The NPIC documentation that we do have gives almost everything you need to know to interface to it. At one point I had a logic analyzer hooked up to it to confirm some details, which I've since forgotten, but there wasn't anything unexpected.

Yes, I have that document, I ws after the bit assignments in the registers so I
could drive the ROM code correctly. I think I have that from some emulator
source code I found.

Thanks for the information

Andrew