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Caution For the in-circuit emulator, the level of each port 2 pin from which noise has not been removed can be read and tested.
5.3.4 Built-In Pull-Up Resistor
P22 through P27 have built-in pull-up resistors. When they must be pulled up, the built-in pull-up resistors should
be used. Use of the built-in pull-up resistors can reduce the number of the required components and the required
installation space.
The PUO2 bit of the pull-up-resistor-option register (PUO) can specify whether to use the built-in pull-up resistors
at P22 through P27, for all six pins at one time. (It is impossible to specify use of the built-in pull-up resistor for
an individual bit independently of the other bits.)
P20 or P21 does not have a built-in pull-up resistor.
7
PUO
0
PUO6
Remark Resetting the PUO2 bit to 00H can reduce the required current in the STOP mode.
Fig. 5-7 Port Specified as an Input Port
RD
IN
Fig. 5-8 Built-In Pull-Up Resistor Format
6
5
4
3
2
PUO5
PUO4
PUO3
PUO2
P2n
n = 0 to 7
1
0
0
0
(00H when RESET is input)
PUO2
Specifies pull-up resistor connection of port 2
0
Not connected with port 2
1
Connected with pins P22 to P27
Chapter 5 Port Functions
5
65
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