NEC uPD78P078 - Manual (Page 70)

70
CHAPTER 3 PIN FUNCTION (
µ
PD78078 SUBSERIES)
3.2 Description of Pin Functions
3.2.1 P00 to P07 (Port 0)
These are 8-bit input/output ports. Besides serving as input/output ports, they function as an external interrupt
request input, an external count clock input to the timer, a capture trigger signal input, and crystal connection for
subsystem oscillation.
The following operating modes can be specified bit-wise.
(1) Port mode
P00 and P07 function as input-only ports and P01 to P06 function as input/output ports.
P01 to P06 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 connected to them by defining the pull-up resistor option
register L (PUOL).
(2) Control mode
In this mode, these ports function as an external interrupt request input, an external count clock input to
the timer, and crystal connection for subsystem clock oscillation.
(a) INTP0 to INTP6
INTP0 to INTP6 are external interrupt request input pins which can specify valid edges (rising edge,
falling edge, and both rising and falling edges). INTP0 or INTP1 becomes a 16-bit timer/event counter
capture trigger signal input pin with a valid edge input.
(b) TI00
Pin for external count clock input to 16-bit timer/event counter
(c) TI01
Pin for capture trigger signal to capture register (CR00) of 16-bit timer/event counter
(d) XT1
Crystal connect pin for subsystem clock oscillation
3.2.2 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 connected to them by defining the pull-up resistor option register L
(PUOL).
(2) Control mode
These ports function as A/D converter analog input pins (ANI0 to ANI7). The pull-up resistor is automatically
disabled when the pins are specified for analog input.