"The Missing Module"
Pairing this module with S. Cousins SC108 (CPU+memory) or SC114 SBC form a complete CP/M computer system.
The beauty with #61 is that it can be used as a
1) bus clock
2) serial interface
4) or a combination of these functions.
In addition, it allows the CPU to run asynchronously up to 24Mhz (Z80) or 33Mhz (Z180)