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CHAPTER 3 PIN FUNCTION (
µ
PD78078 SUBSERIES)
3.2.6 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 connected
by defining the pull-up resistor option register L (PUOL).
(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 on-chip pull-up resistor is automatically disabled.
3.2.7 P60 to P67 (Port 6)
These are 8-bit input/output ports. Besides serving as input/output ports, they are used for control in external
memory expansion mode. P60 to P63 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 or output ports with
port mode register 6 (PM6).
P60 to P63 are N-ch open-drain outputs. Mask ROM version can contain pull-up resistors with the mask
option.
When P64 to P67 are used as input ports, on-chip pull-up resistors can be connected by defining the pull-
up resistor option register L (PUOL).
(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 on-chip 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.