NEC uPD78056Y - Manual (Page 80)

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CHAPTER 4 PIN FUNCTION (
µ
PD78054Y Subseries)
4.2 Description of Pin Functions
4.2.1 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 in 1-bit units.
(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 in 1-bit units 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
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