HP71MultiMod Repository

A ROM Emulator Board for the HP-71B

This repository contains the source and data files associated with the MultiMod ROM emulator board. The board fits into the Card Reader well of the HP-71B and can be used with an optional enclosure.

The emulator is easily programmed using just a USB to TTL Serial cable. The emulator can enumerate up to 112 KB of ROM images stored in 7 16 KB "chips" that can be combined to form ROMs of size 16 KB, 32 KB, 48 KB, or 64 KB.

Further details on the ROM emulator, how it works and how to use it, can be found in the User Manual.

Directory structure

• The BIN directory will contain ROM images in .BIN format. For the moment, images of HP ROMs are not present. ROM images available from and hosted by others will only be added by permission. Links will be provided in the meantime.
• The data files containing ROM images can be found in the DAT directory.
• The HEX directory will contain files that can be used to program the PIC processor in the MultiMod directly using a Microchip programmer and IPE software.
• The LIF directory contains floppy disk images in HP's proprietary LIF format. These images contain various useful programs.
• The doc directory contains documentation for the MultiMod emulator as well as for some of the ROM images.
• The utils directory contains useful utilities, including python scripts to convert .BIN files into the .DAT files used by the MultiMod serial monitor.
• The src directory contains the MPASM assembly source files used to program the MultiMod PIC processor. Version 5.35 or earlier of the Microchip MPLAB IDE X is needed to use the MPASM assembler and linker.