R-IN32M4-CL3 User's Manual: Board design edition
3. Clock Input Pins
R18UZ0074EJ0100
Page 7 of 61
Dec 24, 2019
3.
Clock Input Pins
3.1
Pin Functions
This is a list of pin functions of clock input pins.
Pin Name
Attribute
Function
XT1
I/O
Connects an external oscillator.
When OSCTH = 0, this pin functions as an output pin.
In external clock input mode (OSCTH = 1), drive XT1 to the low level.
XT2
Input
Connects an external oscillator.
In external clock input mode (OSCTH = 1), the clock signal from an external oscillator is
input via XT2.
OSCTH
Note
Input
Selects the clock oscillation source to be connected to the clock pin.
Low level: XT1 and XT2 are to be connected to a resonator.
High level: XT2 is to be connected to an oscillator.
Caution:
For the AC characteristics of the input clock, refer to Section 29.8.1 (1) “Input Clock” in the
“R-IN32M4-CL3 User's Manual: Hardware edition”.
Note:
Connection with an oscillator is recommended.