Posted on May 17, 2011 at 12:07 There are pretty significant differences. The MCU ports (P1, P3, and P4) basically have the same electrical characteristics as the Intel 8032AH MCU. This means that they're TTL-compatible and not CMOS technology. The PSD ports ARE CMOS ports which means that have much higher Voh and lower Vol. Additionally, they're capable of sinking / sourcing far more current than the MCU ports. Finally, the PSD ports can interact with the programmable logic to automatically serve different functions (chip selects, etc.).
