R01UH0823EJ0100 Rev.1.00
Page 199 of 1823
Jul 31, 2019
RX23W Group
9. Clock Generation Circuit
9.4.2
Handling of Pins When Sub-Clock is Not Used
If the sub-clock is not in use, connect the XCIN pin to VSS via a resistor (to pull VSS down) and leave the XCOUT pin
open-circuit as shown in
In addition, if an oscillator is not connected, set the sub-clock oscillator stop bit (SOSCCR.SOSTP) to 1 (stopping the
oscillator) and the sub-clock oscillator control bit in RTC control register 3 (RCR3.RTCEN) to 0 (stopping the sub-clock
oscillator). The value of some RTC registers related to the sub-clock will be undefined after a cold start. Accordingly, be
sure to set these bits after a cold start.
Figure 9.9
Pin Handling when Sub-Clock is Not Used
Open
XCOUT
XCIN