UPD784938 Datasheet, PDF (197/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 6 PORT FUNCTIONS
6.11.4 On-chip pull-up resistors
Port 10 incorporates pull-up resistors. Use of these internal resistors when pull-up is necessary enables the number of parts
and the mounting area to be reduced.
Whether or not an on-chip pull-up resistor is to be used can be specified for each pin by setting the PUOH10 bit of the pull-
up resistor option register H (PUOH) and the port 10 mode register (PM10). When PUOH10 is 1, the on-chip pull-up resistors
of the pins for which input is specified by PM10 (PM10n = 1, n = 0 to 7) are enabled.
Also, the specification for use of the pull-up resistor is also valid for pins specified as control mode pins (pull-up resistors are
also connected to pins that function as output pins in the control mode). Therefore, if you do not want to connect the pull-up
resistors in the control mode, the contents of the corresponding bits of PM10 should be set to 0 (output mode).
Figure 6-79. Pull-Up Resistor Option Register H (PUOH) Format
7
6
5
4
3
2
1
0 Address After reset R/W
PUOH 0
0
0
0
0 PUOH10 PUOH9 0 0FF4FH
00H
R/W
PUOH10 Port 10 Pull-Up Resistor Specification
0 Not used in port 10
1 Used in port 10
Remark When STOP mode is entered, setting PUOH to 00H is effective for reducing the current consumption.
Figure 6-80. Pull-Up Specification (Port 10)
VDD
Internal
bus
Input
buffer
(PUOH)
PUOH10
Port 10 mode register
(PM10)
Preliminary User’s Manual U13987EJ1V0UM00
P107
P106
P105
P101
P100
197