Saturday, 1 February 2025

MCLZ8 on Freebee

So it turns out you can emulate a Z80 using a Teensy 4.1. Better yet, with the aid of a few voltage translators on a little interposer board, you can plug the teensy into your Z80 machine and run using the teensy as the processor.

This is kinda huge - the sky's the limit for the debug ability that comes from being able to interrogate everything that's happening at processor level over a dead-basic USB connection.

Luckily, Freebee doesn't need no stinkin' coreboard to run as a basic 32K bee, so the rather tall Teensy + interposer board is no impediment. However the interposer board as layed out on the Microcore website was a bit bulky, so I redid it so it fits neatly under the Teensy. This means a third board is also needed to get back to the normal 0.6" pin pitch for the Z80. I guess I could have used an SMD connector for both Teensy and Z80 socket, but it's easier with through-hole here.

Then we download the MCLZ8 firmware, install the Arduino IDE + Teensy loader, compile the source, and upload the code to the Teensy. And just like that, we have a Z80 hardware emulator in software.

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