Brace yourselves, because Ted is back with — any guesses? Yep, another drop-in emulator, this time for the 16/32-bit Motorola 68000!

Ted Fried aka MicroCore Labs has been featured a fair number of times on the PJRC blog with his Teensy-based drop-in CPU replacements, including the MCL65-Fast Apple II Accelerator, MCLZ8 Zilog Z80 (RIP!) emulator, and MCL64 Commodore 64 Accelerator.

The MCL68+ emulates both the 68k itself, and the local bus interface (at full speed) thanks to Ted’s prior experience and some new tricks. In the case of the Macintosh 512K, the MCL68+ is able to substitute for the original CPU, while bit-banging the bus at the required 7.8MHz. Byte-wide latches based on 74HCT574 flip-flops are used to power the address and data busses due to the sheer amount of I/O required to emulate the m68k. As always, source code can be found on GitHub, and you can see it in action below.