Datasheet

29.4 Signal Description
Table 29-1. Signal Description for PTC
Name Type Description
Y[m:0] Analog Y-line (Input/Output)
X[n:0] Digital X-line (Output)
Note: The number of X- and Y-lines are device dependent. Refer to Configuration Summary for details.
Refer to I/O Multiplexing and Considerations for details on the pin mapping for this peripheral. One signal
can be mapped on several pins.
29.5 System Dependencies
In order to use this Peripheral, configure the other components of the system as described in the
following sections.
29.5.1 I/O Lines
The I/O lines used for analog X-lines and Y-lines must be connected to external capacitive touch sensor
electrodes. External components are not required for normal operation. However, to improve the EMC
performance, a series resistor of 1 kΩ or more can be used on X-lines and Y-lines.
29.5.1.1 Mutual-Capacitance Sensor Arrangement
A mutual-capacitance sensor is formed between two I/O lines - an X electrode for transmitting and Y
electrode for sensing. The mutual capacitance between the X and Y electrode is measured by the
Peripheral Touch Controller.
Figure 29-3. Mutual Capacitance Sensor Arrangement
PTC
Module
MCU
X
0
X
n
Y
0
Y
m
X
1
Y
1
Sensor Capacitance C
x,y
C
x0,y0
C
x0,y1
C
x0,ym
C
x1,y0
C
x1,y1
C
x1,ym
C
xn,y0
C
xn,y1
C
xn,ym
PTC
Module
ATmega328PB
PTC - Peripheral Touch Controller
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001906C-page 362