Howdy y'all,

Wersi is a German manufacturer of electronic organs and pianos. Their antique SL-M2 NR.51173 module contains two Zilog Z0861112PSC microcontrollers with programs in diffusion ROM. My buddy David Ryskalczyk politely asked me to photograph that ROM for extraction, and this repo contains the partial result.

The ROM is advertised as 4kB, but it is arranged as 130 rows and 256 columns totaling 33,280 bits. The extra 512 bits hold a test ROM that is independent of the application. This test ROM is documentation by Zilog.

To edit the bit markings, simply open rom10x.bmp in Mask ROM Tool. make rom10x.txt will produce an ASCII art of the bits in physical order.

We don't yet know the proper decoding into physically ordered bytes, but it's possible that the GatoROM program can solve the ordering or be extended to support it. It's also possible that GatoROM and MaskRomTool will need to be extended with support for Z8's format.

If you figure out the bit ordering, or if you happen to have implemented the electronic backdoor method of dumping the ROM, please get in touch.

Happy hunting,

--Travis Goodspeed