What is HP-42X?

It is an HP-42S Extended MicroCode Emulator for HP-48GX/SX and HP-49G calculators. This famous vintage calculator is fully recreated because I emulated the real CPU behavior and the emulator executes a code from the real HP-42S ROM. Beside the emulation, I added some advanced features (like 96K of HP-42 RAM and 16/30/31K+32K of Port 1/2 RAM) to the original specifications.

There are few variations of HP-42X according to the various calculator configurations and different user needs. These are:

HP42X48: The EXTENDED (96K+31K+32K) version for HP-48GX with a 128K RAM card in Slot1 and >=128K RAM card in Slot2. Uses one RAM card for the HP-42/Emulator ROM and another for the HP-42/Emulator RAM.

HP42X48E: The EASY (32K) version for HP-48GX with only one >=128K RAM card in either Slot1 or Slot2. Uses RAM card for the HP-42/Emulator ROM and main calculator RAM for the HP-42/Emulator RAM.

HP42X48L: The LITE (96K+16K+32K) version for HP-48GX with only one >=128K RAM card in either Slot1 or Slot2. Uses RAM card for the HP-42/Emulator ROM and Port0 for the HP-42/Emulator RAM.

HP42X48S: The EXTENDED (96K+31K+32K) version for HP-48SX with a 128K RAM card in Port1 and another 128K RAM card in Port2. Uses one RAM card for the HP-42/Emulator ROM and another for the HP-42/Emulator RAM.

HP42X48D: The DEMO (8K) version for HP-48GX with only one >=128K RAM card in either Slot1 or Slot2. Uses RAM card for the HP-42/Emulator ROM and main calculator RAM for the HP-42/Emulator RAM.

HP42X49: The EXTENDED (96K+31K+32K) version for HP-49G with both banks of Port1 empty. Uses one bank for the HP-42/Emulator ROM and another for the HP-42/Emulator RAM (uses the whole Port1).

HP42X49E: The EASY (32K) version for HP-49G with only one bank of Port1 empty. Uses this bank for the HP-42/Emulator ROM and main calculator RAM for the HP-42/Emulator RAM. version is especially suitable for use with HP-41X because it allows you to have both HP-41X and HP-42X installed together (into Port1).

HP42X49L: The LITE (96K+30K+32K) version for HP-49G with only one bank of Port1 empty. Uses this bank for the HP-42/Emulator ROM and Port0 for the HP-42/Emulator RAM. This version is especially suitable for use with HP-41X because it allows you to have both HP-41X and HP-42X installed together (into Port1).

HP42X49D: The DEMO (8K) version for HP-49G with only one bank of Port1 empty. Uses this bank for the HP-42/Emulator ROM and and main calculator RAM for the HP-42/Emulator RAM.

The numbers in the parenthesis are the amount of the HP-42 and port RAM (Port1+Port2).

Here are few samples captured from the emulator running under Emu48 for Windows:

Installation guide with description of many other (advanced) features is here.

Please, keep in mind that HP-42X is not a free software.
If you want to buy one, you can find the necessary info here.
Demo version can be obtained at request.