Epson HX-20 ROM dump

Epson HX-20 ROM dump

The ROMs in the HX-20 are almost, but not exactly compatible with 2764 EPROMS. So my smart DATA IO programmer would not read them. But the HX-20 has a BASIC and a serial port, so a small program and a lot of patience will do the trick. It is simple and dumps only one ROM at the time. If you want another range, you have to change line 100.

Somehow I do not seem to get the HX-20 BASIC to calculate a proper checksum, boolean arithmetic is not present. Maybe I'll fix this later. The files below have a corrected checksum, so should be accepted by EPROM programmers.

The output format is currently Intel Intellec 8/MDS Format. The Motorola Exorciser (S1) Format would be more appropriate, but I leave this to the reader.

What you also need;

The download stuff:

Marco Orlandi send a ROM set dump of a HX-20 with a french keyboard. Only the Monitor and Utility ROM differ. An other tip is for reading these ROMs with a standard programmer. Connect pins 1,26,27,28 and setting CS (chip select) to active high. Then the ROMS read as a Nec 2764.

Last update: 2017-06-06