RL78/G13 CHAPTER 4 PORT FUNCTIONS
R01UH0146EJ0100 Rev.1.00 187
Sep 22, 2011
4.2.4 Port 3
Port 3 is an I/O port with an output latch. Port 3 can be set to the input mode or output mode in 1-bit units using port
mode register 3 (PM3). When the P30 to P37 pins are used as an input port, use of an on-chip pull-up resistor can be
specified in 1-bit units by pull-up resistor option register 3 (PU3).
Input to the P35 to P37 pins can be specified as analog input or digital input in 1-bit units, using port mode control
register 3 (PMC3).
This port can also be used for external interrupt request input, real-time clock correction clock output, clock/buzzer
output, timer I/O, and A/D converter analog input.
Reset signal generation sets P30 to P34 to input mode, and sets P35 to P37 to analog input.
Table 4-7. Settings of Registers When Using Port 3
Pin Name
Name I/O
PM3× PMC3×
Alternate Function Setting
Note 6
Remark
Input 1
− ×
P30
Output 0
RTC1HZ output = 0
Note 1
SCK11/SCL11 output = 0
Note 2
Input 1
− ×
P31
Output 0
TO03 output = 0
Note 3
PCLBUZ0 output = 0
Note 4
(PCLBUZ0 output = 0
Note 5
)
Input 1
− ×
P32 to P34
Output 0
×
Input 1 0
×
P35 to P37
Output 0 0
×
Notes 1. To use P30/RTC1HZ/INTP3 as a general-purpose port, set bit 5 (RCLOE1) of real-time clock control
register 0 (RTCC0) to “0”, which is the same as its default status setting.
2. To use P30/INTP3/RTC1HZ/SCK11/SCL11 as a general-purpose port in 20-pin to 100-pin products, set
serial channel enable status register 0 (SE0), serial output register 0 (SO0) and serial output enable
register 0 (SOE0) to the default status.
3. To use P31/TI03/TO03/INTP4 as a general-purpose port, set bit 3 (TO03) of timer output register 0 (TO0)
and bit 3 (TOE03) of timer output enable register 0 (TOE0) to “0”, which is the same as their default status
setting.
4. To use P31/TI03/TO03/INTP4/PCLBUZ0 as a general-purpose port in 24- to 44-pin products, set bit 7
(PCLOE0) of clock output select register 0 (CKS0) to “0”, which is the same as their default status setting.
5. To use P31 as a general-purpose port, do not set PIOR3 set to 1.
6. The descriptions in parentheses indicate the case where PIORx = 1.
Remark ×: don’t care
PM3×: Port mode register 3
PMC3×: Port mode control register 3
PIOR×: Peripheral I/O redirection register
<R>
<R>
<R>
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