Datasheet

CHAPTER 4 PORT FUNCTIONS
User’s Manual U18698EJ1V0UD
93
4.2.8 Port 14
Port 14 is a 4-bit I/O port with an output latch. Port 14 can be set to the input mode or output mode in 1-bit units
using port mode register 14 (PM14). When the P140 to P143 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 14 (PU14).
This port can also be used for segment output.
Reset signal generation sets port 14 to input mode.
Figure 4-14 shows a block diagram of port 14.
Figure 4-14. Block Diagram of P140 to P143
P140/SEG8 to
P143/SEG11
RD
WR
PORT
WR PM
Output latch
(P140 to P143)
PM140 to PM143
PM14
WR PU
PU140 to PU143
P-ch
PU14
Selector
Selector
Internal bus
P14
V
DD
LCD controller/driver
WR PF
PF14ALL
PFALL
P14: Port register 14
PU14: Pull-up resistor option register 14
PM14: Port mode register 14
PFALL: Port function register ALL
RD: Read signal
WR××: Write signal