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CHAPTER 4 PIN FUNCTION (
μ
PD780024Y, 780034Y SUBSERIES)
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 interrupt request flag (KRIF) can be set to 1 by detecting a falling edge.
The following operating mode can be specified bit-wise.
(1) Port mode
These ports function as 8-bit input/output ports. They can be specified bit-wise for input or output ports by using
the port mode register 4 (PM4). When they are used as input ports, on-chip pull-up resistors can be used by
setting pull-up resistor option register 4 (PU4).
(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 pull-up resistor is automatically disabled.
4.2.6 P50 to P57 (Port 5)
These are 8-bit input/output ports. Besides serving as input/output ports, they function as an address bus.
Port 5 can drive LEDs directly.
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/output ports with port
mode register 5 (PM5). When they are used as input ports, on-chip pull-up resistors can be used by setting pull-
up resistor option register 5 (PU5).
(2) Control mode
These ports function as high-order address bus pins (A8 to A15) in external memory expansion mode. When
pins are used as an address bus, the pull-up resistor is automatically disabled.
4.2.7 P64 to P67 (Port 6)
These are 4-bit input/output ports. Besides serving as input/output ports, they are used for control in external
memory expansion mode.
The following operating modes can be specified bit-wise.
(1) Port mode
These ports function as 4-bit input/output ports. They can be specified bit-wise as input or output ports with port
mode register 6 (PM6).
When they are used as input ports, on-chip pull-up resistors can be used by setting pull-up resistor option register
6 (PU6).
(2) Control mode
These ports function as control signal output pins (RD, WR, WAIT, ASTB) in external memory expansion mode.
When a pin is used as a control signal output, the pull-up resistor is automatically disabled.
Caution
When external wait is not used in external memory expansion mode, P66 can be used as an
input/output port.