R01UH0823EJ0100 Rev.1.00
Page 1529 of 1823
Jul 31, 2019
RX23W Group
43. Capacitive Touch Sensing Unit (CTSU)
43.4.4
Notes on Forcibly Stopping Operation
To forcibly stop the current operation, write 0 to the CTSUCR0.CTSUSTRT bit and 1 to the CTSUCR0.CTSUINIT bit at
the same time. After this setting, the operation is stopped and the internal control registers are initialized.
When the CTSUCR0.CTSUINIT bit is used for initialization, the following registers are initialized in addition to the
initialization of the internal measurement state.
CTSUMCH0 register
CTSUMCH1 register
CTSUST register
CTSUSC counter
CTSURC counter
If operation is forcibly stopped, an interrupt request may be generated depending on the internal state. After operation is
forcibly stopped, perform the processing for stopping/disabling the DTC or ICU.
If DTC transfer is stopped in the mounted system for some reason, also perform the processing for forcibly stopping and
initializing the CTSU.
43.4.5
TSCAP Pin
The TSCAP pin requires an external decoupling capacitor to stabilize CTSU internal voltage. The traces between the
TSCAP pin and the capacitor, and the capacitor and ground should be as short and wide as physically possible.
The capacitor connected to the TSCAP pin should be fully discharged using I/O port control to output a low level, before
turning on the switch (CTSUCR1.CTSUCSW bit = 1) to establish a connection.
43.4.6
Notes during Measurement Operation (CTSUCR0.CTSUSTRT Bit = 1)
During measurement operation (CTSUCR0.CTSUSTRT bit = 1), do not use settings such as “stop the peripheral module
clock” or “change the port settings related to the touch pins (TS and TSCAP pins)” in the higher layers of the system.
If control settings non-compliant to these restrictions are made, after operation is forcibly stopped
(CTSUCR0.CTSUSTRT bit = 0 and CTSUCR0.CTSUINIT bit = 1), write 0 to the CTSUCR1.CTSUPON bit and 0 to the
CTSUCR1.CTSUCSW bit at the same time, and set the CTSUCR0.CTSUSNZ bit to 0. Then, restart from the initial
setting flow shown in