NEC NEC PD78081(A), User Manual

Page: 40 / 274

17
CHAPTER 2 PIN FUNCTION
2.2 Description of Pin Functions
2.2.1 P00 to P03 (Port 0)
These are 4-bit input/output ports. Besides serving as input/output ports, they function as an external interrupt
request input.
The following operating modes can be specified bit-wise.
(1) Port mode
P00 functions as input-only port and P01 to P03 function as input/output ports.
P01 to P03 can be specified for input or output ports bit-wise with a port mode register 0 (PM0). When they
are used as input ports, on-chip pull-up resistors can be used to them by defining the pull-up resistor option
register L (PUOL).
(2) Control mode
INTP1 to INTP3 function as external interrupt request input pins which are capable of specifying the valid edges
(rising edge, falling edge, and both rising and falling edges).
2.2.2 P10 to P17 (Port 1)
These are 8-bit input/output ports. Besides serving as input/output ports, they function as an A/D converter analog
input.
The following operating modes can be specified bit-wise.
(1) Port mode
These ports function as 8-bit input/output ports.
They can be specified bit-wise as input or output ports with a port mode register 1 (PM1). If used as input
ports, on-chip pull-up resistors can be used to these ports by defining the pull-up resistor option register L
(PUOL).
(2) Control mode
These ports function as A/D converter analog input pins (ANI0-ANI7). The on-chip pull-up resistor is
automatically disabled when the pins specified for analog input.