Because the project itself will be a cross-continent multi-site project. Partitioned in modules helps different folks in focusing their own parts based on the common interface without worrying about bumping into each other in fighting for the same port. For example:

1. Keypad of push buttons can be implemented in both matrix fashion (more io pins required) and ADC fashion (only one IO pin required). They can be put into two (or one) child boards.

2. Moto control boards can be in many variants, e.g. on/off stepper or pwm type. People can easily replace one module with another in both HW and SW. It is critical to feed the motor power and provide other protection on the child board.

3. People can make their own child boards to try their own circuits.

We can use the same idea of PC/104, which uses 104 pins for PC ISA-bus compatible. How about we coin our standard as MCU/52 (or MC/51) with 52(51) pins. Short introduction on PC/104 can be found at http://www.controlled.com/pc104/techp1.html

Even x51 can not live forever, it sure can live longer than I can. Why not organize our own society and promote our own standard, by the people and not by the companies, you know what I mean.

Regards, Oliver

Regards, Oliver

Regards, Oliver