It's basically an option ROM but contains 8 different images. The first is a menu selection pick which ROM you want active and the other 7 are normal option ROMs. The menu selection ROM also has ram tests, video test cards and a JiffyDOS selection that allows you to turn off and on older "Switched" JiffyDOS installs by replacing the toggle switch with a wire from this board.
It remember state through power down so no re-selecting the ROM every time you turn it on, it stays as you left it.
That sounds really cool (and no rule violations I see). But can you explain how it remembers the state after power-down? Sure I/we can follow the link if bored (time to kill), but if you can write a little more detail we would appreciate it!
Following your link I didn't find much more detail (perhaps I missed something?) I did see that you are "Out of Stock" which (I presume) means business is good?! Always nice to see a fellow Commie succeed!
Anyway, Happy New Year and thanks for sharing your "C128 Multi-ROM" with us!
It's artificially out of stock while I try and make the installation idiot proof. We are waiting for new cable clips that can easily be attached to the pin of U3 (existing ones suck).
It stores the state in eeprom contained inside the PIC micro controller that actually does the rom selection. When you set menu options data data is actually written to an unused memory address that is decoded by U3 inside the 128, the PIC sees that and saves it.
The multirom works on ANY C128. They all have the U36 option rom slot where it fits. The option to control JiffyDos is simple an output from the board (1 or 2 wires) that go to the address select on your JD Rom. The roms have to be laid out in such a way as the select lines work, but if you have a JD with a switch you can control it with this instead. This does NOT replace or include any kernal/JiffyDos rom. It simply has the switching output to control which rom bank is selected if a suitable one is installed.