IBM nec pd78p081(a2) User Manual

This is an 2-bit input/output port with output latches.  Input mode/output mode can be specified bit-wise by means

of port mode register 10 (PM10).  When pins P100 to P101 are used as input port pins, an on-chip pull-up resistor

can be used as an 2-bit unit by means of pull-up resistor option register H (PUOH).

These pins are dual function pins and serve as timer inputs/outputs.

RESET input sets the input mode.

The port 10 block diagram is shown in Figure 4-9.

PUO :  Pull-up resistor option register

PM

:  Port mode register

RD

:  Port 10 read signal

WR :  Port 10 write signal

P-ch

WR

PM

WR

PORT

RD

WR

PUO

V

DD

Selector

PUO10

Output Latch
(P100 to P101)

PM100 to PM101

Internal bus

P100/TI5/TO5,
P101/TI6/TO6

Alternate

Functions