CHAPTER 4 PORT FUNCTIONS
Preliminary User’s Manual U19014EJ1V0UD
78
(3) Pull-up resistor option registers (PU0, PU1, PU3, and PU12)
These registers specify whether the on-chip pull-up resistors of P00 and P01, P10 to P17, P30 to P33, or P120
are to be used or not. On-chip pull-up resistors can be used in 1-bit units only for the bits set to input mode of the
pins to which the use of an on-chip pull-up resistor has been specified in PU0, PU1, PU3, and PU12. On-chip
pull-up resistors cannot be connected to bits set to output mode and bits used as alternate-function output pins,
regardless of the settings of PU0, PU1, PU3, and PU12.
These registers can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation sets these registers to 00H.
Figure 4-17. Format of Pull-up Resistor Option Register
7
0
Symbol
PU0
6
0
5
0
4
0
3
0
2
0
1
PU01
0
PU00
Address
FF30H
After reset
00H
R/W
R/W
PU17
PU1
PU16
PU15
PU14
PU13
PU12
PU11
PU10
FF31H
00H
R/W
0
PU3
0
0
0
PU33
PU32
PU31
PU30
FF33H
00H
R/W
0
PU12
0
0
0
0
0
0
PU120
FF3CH
00H
R/W
PUmn
Pmn pin on-chip pull-up resistor selection
(m = 0, 1, 3, 12; n = 0 to 7)
0
On-chip pull-up resistor not connected
1
On-chip pull-up resistor connected
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