How much drive is available from DOMINO’s port pins?
DOMINOs have two kinds of parallel ports. The CMOS Port1 pins on both DOMINO and DOMINO-2 sink 1.6mA and source 10uA. On DOMINO-2 there is a co-processor with additional parallel I/O. The co-processor’s PA0-7 and PB0-7 lines, can source or sink 20mA. NOTE: when the DOMINO-2 is powered down with the real time clock battery-backed, the co-processor’s I/O remains in the last state before power down. If these I/O pins are left in an active state, driving external circuitry, this power has to come from the back-up battery. Leaving co-processor I/O pins active during battery-backup drains the batteries. To prevent excessive battery drain when using the real time clock, make sure all co-processor I/O is placed in a non-active mode before powering the DOMINO-2 down.
