R01UH0823EJ0100 Rev.1.00
Page 1528 of 1823
Jul 31, 2019
RX23W Group
43. Capacitive Touch Sensing Unit (CTSU)
43.4
Usage Notes
43.4.1
Measurement Result Data (CTSUSC and CTSURC Counters)
Read access during measurement is prohibited. If the measurement result data is accessed, an incorrect value may be read
due to asynchronous operation.
43.4.2
Software Trigger
When 10b (PCLK/4) is selected by the CTSUCR1.CTSUCLK[1:0] bits, to restart measurement by writing 1 to the
CTSUCR0.CTSUSTRT bit after measurement has been completed, wait for at least three cycles to elapse after an
interrupt is generated, and then write to the CTSUCR0.CTSUSTRT bit.
Figure 43.21
Notes on Restarting Measurement
43.4.3
External Trigger
If an external trigger is input during the measurement time, measurement is not started. The next external event is
enabled after one cycle of the operating clock when a CTSUFN interrupt is generated.
To stop external trigger mode, write 0 to the CTSUCR0.CTSUSTRT bit and 1 to the CTSUCR0.CTSUINIT bit at
the same time (forced stop).
CTSUSTRT
PCLK
CTSUFN interrupt
Writing 1 to CTSUSTRT (restart) is disabled
Automatically cleared by CTSU
Restart setting is possible (fastest)