Cautions On Specifying The Pin Settings - Renesas RL78/G1P Hardware User Manual

RL78/G1P

4.6.2 Cautions on specifying the pin settings

If the output function of an alternate function is assigned to a pin that is also used as an output pin, the output of the
unused alternate function must be set to its initial state so as to prevent conflicting outputs. For details about the alternate
output function, see 4.5 Settings of Port Related Register When Using Alternate Function.
No specific setting is required for input pins because the output function of their alternate functions is disabled (the
buffer output is Hi-Z).
The following indicates the specific targets and the method of processing.
Affected Unit Output or I/O Pins
Timer array units TO0n
Clock/buzzer PCLBUZn
output circuit
Serial array units SCK00, SO00,
TxD0
IICA SCLAn, SDAAn
Example: P12/TI03/TO03/INTP4/PCLBUZ0 pin
(1) When the pin is used as PCLBUZ0 output
P12: Specify the output mode by setting PM12 of port mode register 1 to 0.
TI03, INTP4: These are input pins, so this note does not apply.
TO03: This is an output pin, so set TO01 and TOE01 of timer array unit 0 to 0.
(2) When the pin is used as TO03 output
P12: Specify the output mode by setting PM12 of port mode register 1 to 0.
PCLBUZ0: This is an output pin, so set PCLOE0 of clock/buzzer output to 0, respectively.
TI03: This is an input pin, so this note does not apply.
Like TxD0 when using the P30/INTP2/TxD0/TOOLTxD/SO00 pin as the SO00 output pin, changing the operation mode
does not enable alternate functions assigned to pins on the same serial channel, and this note does not apply to such pins.
(If the CSI function is specified (MD002 = MD001 = 0), the pin does not function as a UART pin, and therefore TxD0
output is invalid.)
Disabling the unused functions, including blocks that are only used for input or do not have I/O, is recommended to
lower power consumption.
R01UH0895EJ0100 Rev.1.00
Nov 29, 2019
Table 4-15. Handling of Unused Alternate Functions
of Unused
Alternate
Functions
Make sure that bit n (TO0n) of timer output register 0 (TO0) and bit n (TOE0n) of timer
output enable register 0 (TOE0) are set to their initial value (0).
Make sure that bit 7 (PCLOEn) of clock output select register n (CKSn) is set to its
initial value (0).
Make sure that bit 0 (SE00) of serial channel enable status register 0 (SE0), bit 0
(SO00) of serial output register 0 (SO0), and bit 0 (SOE00) of serial output enable
register 0 (SOE0) are set to their initial value (1 for SO00 and 0 for others).
Disable the IICA operation by setting bit 7 (IICEn) of the IICCTLn0 register to 0.
CHAPTER 4 PORT FUNCTIONS
Handling of Unused Alternate Functions
95