
CHAPTER 4 PORT FUNCTIONS
Preliminary User’s Manual U16315EJ1V0UD
100
(2) Pull-up resistor option registers (PU0, PU1, PU3, PU7, PU12, and PU14)
These registers specify whether the on-chip pull-up resistors of P00 to P03, P10 to P17, P30 to P33, P70 to P77,
P120, or P140 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, PU7,
PU12, and PU14. On-chip pull-up resistors cannot be used for bits set to output mode and bits used as alternate-
function output pins, regardless of the settings of PU0, PU1, PU3, PU7, PU12, and PU14.
These registers can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input clears these registers to 00H.
Caution
Use of a pull-up resistor can be specified for P60 to P63 pins by a mask option only in the mask
ROM versions.
Figure 4-20. Format of Pull-up Resistor Option Register
7
0
Symbol
PU0
6
0
5
0
4
0
3
PU03
2
PU02
1
PU01
0
PU00
Address
FF30H
After reset
00H
R/W
R/W
7
PU17
PU1
6
PU16
5
PU15
4
PU14
3
PU13
2
PU12
1
PU11
0
PU10
FF31H
00H
R/W
7
0
PU3
6
0
5
0
4
0
3
PU33
2
PU32
1
PU31
0
PU30
FF33H
00H
R/W
7
PU77
PU7
6
PU76
5
PU75
4
PU74
3
PU73
2
PU72
1
PU71
0
PU70
FF37H
00H
R/W
7
0
PU12
6
0
5
0
4
0
3
0
2
0
1
0
0
PU120
FF3CH
00H
R/W
7
0
PU14
6
0
5
0
4
0
3
0
2
0
1
0
0
PU140
FF3EH
00H
R/W
PUmn
Pmn pin on-chip pull-up resistor selection
(m = 0, 1, 3, 7, 12, 14; n = 0 to 7)
0
On-chip pull-up resistor not connected
1
On-chip pull-up resistor connected