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Chapter 2
Pin Function (μPD780828A Subseries)
User’s Manual U16504EE1V1UD00
2.3.4 P34 to P37 (Port 3)
These are 4-bit input/output ports. Besides serving as input/output ports, they function as data input/
output to/from and clock input/out of the serial interface. Additionally they function as timer input/output
and segment signal output of the LCD controller/driver.
The port mode and the port function 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 the port mode register 3.
(2)
Control mode
These ports function as timer input/output, as serial interface data input/output, serial clock
input/output and as LCD segment output.
(a) SI30, SO30
Serial interface serial data input/output pins.
(b) SCK30
Serial interface serial clock input/output pin.
(c) TI50
Pin for external count clock input to 8-bit timer/event counter.
(d) TO50
Pin for output of the 8-bit timer/event counter.
(e) S24 to S27
Pins for segment output signals of the LCD controller/driver.
Caution:
When this port is used as a serial interface, the I/O function and output latches must
be set according to the function the user requires.
2.3.5 P40 to P47 (Port 4)
This is an 8-bit input/output port. Besides serving as input/output port, they function as segment signal
output pins of the LCD controller/driver.
The following operating modes can be specified bit-wise or byte-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 4.
(2)
Control mode
These port function as segment output signal pins (S0 to S7) of the LCD controller/driver and can
specified byte-wise.