NEC 78014Y Series, User Manual

Page: 67 / 547

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CHAPTER 3 PIN FUNCTION (
µ
PD78014 Subseries)
67
3.2 Description of Pin Functions
3.2.1 P00 to P04 (Port 0)
These are 5-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 clock oscillation.
The following operating modes can be specified bit-wise.
(1) Port mode
P00 and P04 function as input-only ports 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, a pull-up resistor can be connected to them with an on-chip pull-up resistor option register
(PUO).
(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 INTP3
INTP0 to INTP2 are external interrupt request input pins which can specify valid edges (rising edge, falling
edge, and both rising and falling edges). INTP0 becomes a 16-bit timer/event counter capture trigger signal
input pin with a valid edge input. INTP3 becomes a falling edge detection external interrupt request input
pin.
(b) TI0
TI0 is a pin for external count clock input to 16-bit timer/event counter.
(c) XT1
Crystal connection pin for subsystem clock oscillation