Renesas RX Series User Manual

R01UH0823EJ0100 Rev.1.00 Page 1521 of 1823
Jul 31, 2019
RX23W Group 43. Capacitive Touch Sensing Unit (CTSU)
Figure 43.15 Timing Chart of Self-Capacitance Multi-Scan Mode
(Measurement Start Condition is Software Trigger)
The following describes operation shown in the timing chart in Figure 43.15.
(1) After various settings are made, operation is started by writing 1 to the CTSUCR0.CTSUSTRT bit.
(2) After a channel to be measured is determined according to the preset conditions, a request for setting the
corresponding channel (CTSUWR) is output.
(3) Upon completion of writing the measurement channel settings (CTSUSSC, CTSUSO0, and CTSUSO1 registers),
the sensor drive pulse is output and the sensor ICO clock and the reference ICO clock operate.
(4) After the sensor stabilization wait time and the measurement time have elapsed and measurement is finished, a
measurement result read request (CTSURD) is output.
(5) After a channel to be measured next is determined, a measurement channel setting request (CTSUWR) is output.
(6) After the stabilization wait time has elapsed and when the previous measurement is read, the result is cleared and
measurement is started.
(7) Upon completion of all measurement channels, a measurement end interrupt (CTSUFN) is output and measurement
is finished (transition to Status 0).
Table 43.7 lists the touch pin states in self-capacitance multi-scan mode.
Table 43.7 Touch Pin States in Self-Capacitance Multi-Scan Mode
Status
Touch Pin
Measurement Channel Non-Measurement Channel
0 Low Low
1 Low Low
2 Low Low
3 Pulse Low
4 Pulse Low
5 Low Low
32
Measurement result
4 (During current/count value
conversion)
3
163 2 63
0
CTSUST.CTSUSTC[2:0]
flags (Status)
0 4 (During current/count value conversion) 051
Sensor drive pulse
Measurement time
Operating clock
CTSUCR0.CTSUSTRT bit
1
(1) (3) (6)
CTSUSC counter
N
Measurement result
5
CTSUMCH0 register
(7)
CTSURD interrupt
CTSUWR interrupt
Sensor ICO clock
CTSUFN interrupt
0
12
(4)
Measurement of channel 2 Measurement of channel N
(2)
0
(5)
Sensor stabilization wait time
(CTSUSST register)

Renesas RX Series Specifications

General

Brand	Renesas
Model	RX Series
Category	Microcontrollers
Language	English