R01UH0823EJ0100 Rev.1.00
Page 1515 of 1823
Jul 31, 2019
RX23W Group
43. Capacitive Touch Sensing Unit (CTSU)
43.3.2
Measurement Modes
The CTSU supports self-capacitance and mutual capacitance methods.
illustrates these methods.
Figure 43.8
Overview of Self-Capacitance Method and Mutual Capacitance Method
In the self-capacitance method, a single touch pin is allocated to a single touch key to measure individual electrostatic
capacitance when a finger is in close proximity. In this method, single scan and multi-scan can be used as measurement
modes.
In the mutual capacitance method, the capacitance between two opposite electrodes (transmit and receive pins) is
measured.
Key 1
Key 2
Key 3
Key 4
Key 5
Touch key arrangement for
self-capacitance method
TS0
TS1
TS2
TS3
TS4
TS5
Receive pin
Tr
an
sm
it
p
in
Touch sensor arrangement for
mutual capacitance method
Touch key
TS1 TS2 TS3 TS4 TS5 TS6
