Internal Pull-Up Resistors - NEC uPD784038 Series User Manual

5.2.4 Internal Pull-Up Resistors

Port 0 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 internal pull-up resistor is to be used can be specified for each pin by means of the PUO0 bit of the pull-
up resistor option register (PUO) and the port 0 mode register (PM0). When PUO0 is 1, the internal pull-up resistors of the pins
for which input is specified by PM0 are enabled (PM0n = 1, n = 0 to 7).
7 6
PUO 0 PUO6
Remark When STOP mode is entered, setting 00H in PUO is effective in reducing the power consumption.
Internal
Bus
118
CHAPTER 5 PORT FUNCTIONS
Figure 5-6 Pull-Up Resistor Option Register (PUO) Format
5 4 3 2
PUO5 PUO4 PUO3 PUO2
Figure 5-7 Pull-Up Resistor Specification (Port 0)
Input
Buffer
(PUO)
PUO0
User's Manual U11316EJ4V1UD
1 0 Address After Reset
PUO1 PUO0 0FF4EH
PUO0 Port 0 Pull-Up Resistor Specification
0
Not used in port 0
Used in port 0
1
Port 0 Mode Register
(PM0)
R/W
00H R/W
V
DD0
P07
P06
P05
P01
P00