Renesas rl78 User Manual
RL78/G1A
CHAPTER 4 PORT FUNCTIONS
R01UH0305EJ0200 Rev.2.00
107
Jul 04, 2013
4.3.3 Pull-up resistor option registers (PUxx)
These registers specify whether the on-chip pull-up resistors are to be used or not. On-chip pull-up resistors can be
used in 1-bit units only for the bits set to both normal output mode (POMmn = 0) and input mode (PMmn = 1) for the pins
to which the use of an on-chip pull-up resistor has been specified in these registers. On-chip pull-up resistors cannot be
connected to bits set to output mode and bits used as alternate-function output pins and analog setting (PMC = 1, ADPC =
1), regardless of the settings of these registers.
These registers can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears these registers to 00H (Only PU4 is set to 01H).
Caution When a port with the PIMn register is input from different potential device to the TTL buffer, pull up to
the power supply of the different potential device via an external resistor by setting PUmn = 0.
Figure 4-3. Format of Pull-up Resistor Option Register
Symbol
7 6 5 4 3 2 1 0
Address
After
reset
R/W
PU0
0
PU06 PU05 PU04 PU03
PU02
PU01
PU00
F0030H
00H
R/W
PU1
0
PU16 PU15 PU14 PU13
PU12
PU11
PU10
F0031H
00H
R/W
PU3
0 0 0 0 0 0
PU31
PU30
F0033H
00H
R/W
PU4
0 0 0 0
PU43
PU42
PU41
PU40
F0034H
01H
R/W
PU5
0 0 0 0 0 0
PU51
PU50
F0035H
00H
R/W
PU7 PU77 PU76 PU75 PU74 PU73
PU72
PU71
PU70
F0037H
00H
R/W
PU12
0 0 0 0 0 0 0
PU120
F003CH
00H
R/W
PU14
0 0 0 0 0 0
PU141
PU140
F003EH
00H
R/W
PUmn
Pmn pin on-chip pull-up resistor selection
(m = 0, 1, 3 to 5 , 7, 12, 14; n = 0 to 7)
0
On-chip pull-up resistor not connected
1
On-chip pull-up resistor connected
Caution Be sure to set bits that are not mounted to their initial values.
<R>
<R>