UPD78044F datasheet(40/472 Pages) NEC

40 / 472 page

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.

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.

UPD78044F Datasheet(PDF) 40 Page - NEC