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Hi there.

I am now the proud owner of a 41cx and am looking for some modules for it (I'm in the UK, so they seem quite scarce) and I got to thinking about making one or two.

As we have the ROM files available for most modules, it should be fairly straightforward to burn an EPROM or two to make a module of the required type. Were/are there EPROM modules available for the 41 (3rd party or HP?) and has anyone tried making their own module hardware?

Finally, where can I get the detailed information about the 41's hardware so that I can go about designing a module?

regards

JasonG

Hi,
I have some experience in burning Eproms for HP-41 and HP-71 Eprom Box.

I am working on an FPGA that will behave like an EPROM box, but will use FLASH EPROMS instead. I am nearly finished with the simulations and will then start looking implementing it in real hardware. It will be 2 IC's only: the FPGA (most likely a CPLD) and the FLASH EPROM.
I will soon start working on a full MLDL version with RAM, allowing you to develop your own microcode.
I have a preliminary spec available at www.kuipers.to/hp41

For instance, you need a couple of Eproms for HHP or SCIP 16K Eprom Boxes:
2716 and 2732 in order to generate a 4K (1 MCode page) module. 2732 and 2764 for 8K (2 pages). 2732 and 27128 for a 16K (4 pages).
HHP 32K Eprom for HP-71B use a 2764 (8K module), a 27128 (16K) or a 27256 (32K).

I have made a number of eproms for the HP41. This was done
in the 80's. I still have all the equipment I used to do
this including the MLDL, Mountain computer eprom making
equipment, HHP-16K eprom box made by Hand Held Products(4 of
these) an eprom holder built into a card reader box that slips on the 41, also made by Hand Held Products. If anyone
is interested let me hear from you with an offer.

Of course I'm interested in getting your Mountain Computer IL Eprom Programmer and one of your HHP 16K EBs. Yours.