R01UH0823EJ0100 Rev.1.00 Page 1491 of 1823
Jul 31, 2019
RX23W Group 43. Capacitive Touch Sensing Unit (CTSU)
43.1 Overview
Table 43.1 lists the specifications of the CTSU, and Figure 43.3 shows a block diagram of the CTSU.
As shown in
Figure 43.3, the CTSU consists of the status control block, trigger control block, clock control block,
channel control block, port control block, sensor drive pulse generator, measurement block, interrupt block, and control
registers.
Figure 43.3 CTSU Block Diagram (m = 2, 3, 4, 7, 8, 12, 13, 22, 23, 27, 30, 35)
Table 43.1 CTSU Specifications
Item Description
Operating clock PCLK, PCLK/2, or PCLK/4
Pins TS2, TS3, TS4, TS7, TS8, TS12,
TS13, TS22, TS23, TS27, TS30,
TS35
Electrostatic capacitance measurement pins (12 channels)
TSCAP LPF (low-pass filter) connection pin
Measurement
modes
Self-capacitance single scan
mode
Electrostatic capacitance on a channel is measured by the self-capacitance
method.
Self-capacitance multi-scan mode Electrostatic capacitance on multiple channels is measured successively by the
self-capacitance method.
Mutual capacitance full scan
mode
Electrostatic capacitance on multiple channels is measured successively by
mutual capacitance.
Noise prevention Synchronous noise prevention, high-pass noise prevention
Measurement start conditions
Software trigger
External trigger (event input from the event link controller (ELC))
Table 43.2 CTSU Pin Configuration
Pin Name I/O Function
TS2, TS3, TS4, TS7, TS8, TS12,
TS13, TS22, TS23, TS27, TS30,
TS35
I/O Electrostatic capacitive measurement pins (touch pins)
TSCAP — LPF connection pin
System control block
Trigger
control block
Status
control
Capacitive touch sensing unit (CTSU)
Channel
control block
PCLK
PCLK/2
PCLK/4
Event input from event link
controller (ELC)
Port
control
Measurement block
(counter measurement)
• CTSUSC counter
• CTSURC counter
Clock
control
block
Sensor drive
pulse generator
Interrupt
block
Port control
Sensor drive pulse
Operation enable
Control registers
Offset control
Sensor ICO clock
Reference ICO clock
Port
control
block
Power
supply
DTC
CTSURD interrupt request
Data bus
Memory
CTSUWR interrupt request
CPU ICU
CTSUFN
interrupt request
Diffusion clock
Count
source
H/M
Sensor ICO
Reference ICO
Power supply
control
Diffusion clock
Touch I/O
I/O block
TSCAP
LPF
TSCAP I/O
TSm
ICO: Current-Controlled Oscillator
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