CHAPTER 4 PORT FUNCTIONS
Preliminary User’s Manual U16846EJ1V0UD
80
(3) Pull-up resistor option registers (PU0, PU1, PU3, and PU12)
These registers specify whether the on-chip pull-up resistors of P00 to P03, P10 to P17, P30 to P33, or P120 is to
be used or not. An 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. On-chip pull-up resistor cannot be
connected for 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 input clears these registers to 00H.
Figure 4-16. Format of Pull-up Resistor Option Register
Symbol
7 6 5 4 3 2 1 0
Address
After
reset
R/W
PU0
0 0 0 0
PU03
PU02
PU01
PU00
FF30H
00H
R/W
7 6 5 4 3 2 1 0
PU1 PU17 PU16 PU15 PU14 PU13 PU12 PU11 PU10 FF31H 00H R/W
7 6 5 4 3 2 1 0
PU3
0 0 0 0
PU33
PU32
PU31
PU30
FF33H
00H
R/W
7 6 5 4 3 2 1 0
PU12
0 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