NEC uPD78056Y - Manual (Page 82)

82
CHAPTER 4 PIN FUNCTION (
µ
PD78054Y Subseries)
4.2.4 P30 to P37 (Port 3)
These are 8-bit input/output ports. Beside serving as input/output ports, they function as timer input/output, clock
output, and buzzer output.
The following operating modes can be specified in 1-bit units.
(1) Port mode
These ports function as 8-bit input/output ports. They can be specified in 1-bit units as input or output ports
with port mode register 3 (PM3). When they are used as input ports, on-chip pull-up resistors can be used
by defining the pull-up resistor option register L (PUOL).
(2) Control mode
These ports function as timer input/output, clock output, and buzzer output.
(a) TI1 and TI2
Pin for external count clock input to the 8-bit timer/event counter.
(b) TO0 to TO2
Timer output pins.
(c) PCL
Clock output pin.
(d) BUZ
Buzzer output pin.
4.2.5 P40 to P47 (Port 4)
These are 8-bit input/output ports. Besides serving as input/output ports, they function as an address/data bus.
The test input flag (KRIF) can be set to 1 by detecting a falling edge.
The following operating mode can be specified in 8-bit units.
(1) Port mode
These ports function as 8-bit input/output ports. They can be specified in 8-bit units for input or output ports
by using the memory expansion mode register (MM). When they are used as input ports, on-chip pull-up
resistors can be used by defining the pull-up resistor option register L (PUOL).
(2) Control mode
These ports function as low-order address/data bus pins (AD0 to AD7) in external memory expansion mode.
When pins are used as an address/data bus, the on-chip pull-up resistor is automatically disabled.