Datasheet

CHAPTER 4 PORT FUNCTIONS

User’s Manual U18698EJ1V0UD

4.2.9 Port 15

Port 15 is a 4-bit I/O port with an output latch. Port 15 can be set to the input mode or output mode in 1-bit units

using port mode register 15 (PM15). When the P150 to P153 pins are used as an input port, use of an on-chip pull-up

resistor can be specified in 1-bit units by pull-up resistor option register 15 (PU15).

This port can also be used for segment output.

Reset signal generation sets port 15 to input mode.

Figure 4-15 shows a block diagram of port 15.

Figure 4-15. Block Diagram of P150 to P153

P150/SEG12 to

P153/SEG15

PORT

Output latch

(P150 to P153)

PM150 to PM153

PM15

PU150 to PU153

P-ch

PU15

Selector

Internal bus

P15

LCD controller/driver

PF15ALL

PFALL

P15: Port register 15

PU15: Pull-up resistor option register 15

PM15: Port mode register 15

PFALL: Port function register ALL

RD: Read signal

WR××: Write signal