I received an email from Electronics Goldmine this morning advertising this microprocessor:
https://theelectronicgoldmine.com/products/G26807

Two things found interesting:

* It claims to be upwards compatible with the HD6800. I looked at the data sheet and sure enough the instruction set looks like a 6800 to me. But I am not fluent in that assembly language, so I might be missing something.

* The ominous warning at the bottom! Did they use depleted uranium to make this thing? Following the link at the bottom, since they're based in California and they don't know if it contains any of the hazardous materials listed in the Prop 65 law ( can't afford to test it), they added the warning as a CYA.

Anyway I posted it here because it's a cousin of the 6502, and it is retro enough that someone might want to use it as an I/O controller while staying period accurate.

An interesting processor - it's got the usual microcontroller peripherals, and it has a 7 cycle multiply instruction. However, it has 4k mask ROM on-chip, which is unlikely to be much use, so you'd need to select a mode with external busses and connect to an external ROM, which means some of the I/O gets used for those busses.

Don't go to California; everything can cause cancer out there...

Hitachi is well known as a second source manufacturer. This is their version of the Motorola 6801; a 6800 with on-chip peripherals and some added instructions.

I do like the enhancements Hitachi made - they weren't just doing me-too manufacturing.