SPI and GPIO Outputs - Block Z


        This circuit is designed to for future external expansion.  The complete SPI interface signals can be configured as four other general purpose digital outputs.  These outputs are terminated at proto pads so they would have to be wire to a spare I/O pin of the rear DB-37 auxiliary connector (Block ZZ).  These eight outputs are all at a high impedance level until the MPC555 has finished booting and reconfigured its I/O ports.