Datasheet

RL78/L12 CHAPTER 4 PORT FUNCTIONS
R01UH0330EJ0200 Rev.2.00 108
Dec 13, 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 input mode (PMmn = 1 and POMmn = 0) 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 TTL buffer, pull up to
the power supply of the different potential device via a external pull-up resistor by setting PUmn = 0.
Figure 4-3. Format of Pull-up Resistor Option Register (64-pin products)
Symbol 7 6 5 4 3 2 1 0 Address After reset R/W
PU1 PU17 PU16 PU15 PU14 PU13 PU12 PU11 PU10 F0031H 00H R/W
PU3 0 0 0 0 0 PU32 PU31 PU30 F0033H 00H R/W
PU4 0 0 0 0 PU43 PU42 PU41 PU40 F0034H 01H R/W
PU5 0 0 0 PU54 PU53 PU52 PU51 PU50 F0035H 00H R/W
PU7 0 0 0 PU74 PU73 PU72 PU71 PU70 F0037H 00H R/W
PU12 PU127 PU126 PU125 0 0 0 0 PU120 F003CH 00H R/W
PU14 PU147 PU146 PU145 PU144 PU143 PU142 PU141 PU140 F003EH 00H R/W
PUmn
Pmn pin on-chip pull-up resistor selection
(m = 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
Cautions 1. For the pins used as LCD function pins (SEGxx, CAPL, CAPH, and V
L3), be sure to clear the
corresponding PUmn bit of the PUm register to 0.
2. Be sure to set bits that are not mounted to their initial values. <R>