Atmel Xplained Pro Evaluation Kit for the ATSAMD21J18A Microcontroller ATSAMD21-XPRO ATSAMD21-XPRO Data Sheet

920

Atmel | SMART SAM D21 [DATASHEET]

Atmel-42181C–SAM-D21_Datasheet–07/2014

Note:

1. The number of X and Y lines are device dependent. Refer to 

 for details. 

 for details on the pin mapping for this peripheral. One signal 

can be mapped on several pins. 

In order to use this Peripheral, configure the other components of the system as described in the following sections.

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 K

Ω can be used on X-lines and Y-lines.

A mutual-capacitance sensor is formed between two I/O lines - an X electrode for transmitting and Y electrode for 
receiving. The mutual capacitance between the X and Y electrode is measured by the Peripheral Touch Controller.

X[n:0]

Digital

X-line (Output)

Y[m:0]

Analog

Y-line (Input/Output)

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