USER GUIDE
AT08578: SAM D20 QTouch Robustness Demo
Atmel QTouch
Description
The Atmel | SMART SAM D20 QTouch Robustness Demo demonstrates the
high performance capacitive touch support of the Peripheral Touch Controller
(PTC) while achieving best-in-class conducted immunity and moisture tolerance.
The demo implements a robustness solution that allows customers to easily
incorporate the Atmel QTouch technology into designs that require high levels of
noise immunity and moisture tolerance.
®
®
Features
Six self-capacitance buttons with Philipp Spring
Four mutual-capacitance buttons
Individual LEDs for indicating button status
One 8-channel mutual-capacitance slider
Seven LEDs to indicate slider position
Buzzer for audio feedback
On-board Embedded Debugger module
Connectivity with QTouch Analyzer
On-board Embedded Debugger module for programming/debugging and
QDebug data streaming
Atmel-42324A-SAM-D20-QTouch-Robustness-Demo_UserGuide_102014
Ta bl e of Conte nts
1
2
3
Overview ..................................................................................................................... 3
Hardware Description ................................................................................................. 4
2.1
Block Diagram ....................................................................................................................................... 4
Pin Configuration ........................................................................................................ 5
3.1
3.2
3.3
3.4
Mutual Capacitance Sensors ................................................................................................................ 5
Self Capacitance Sensors ..................................................................................................................... 5
Indication ............................................................................................................................................... 6
Communication Interface ...................................................................................................................... 6
4
5
Unit Assembly ............................................................................................................. 7
Powering up the Kit ..................................................................................................... 8
5.1
5.2
USB Port ............................................................................................................................................... 8
External DC Power Supply .................................................................................................................... 8
6
7
8
Embedded Debugger (EDBG) ..................................................................................... 9
Connecting to QTouch Analyzer .............................................................................. 10
Switch Operation ....................................................................................................... 12
8.2
8.3
Noise Handling .................................................................................................................................... 12
Moisture Tolerance.............................................................................................................................. 12
9
Board Operation ........................................................................................................ 13
9.1
9.2
Product Layout .................................................................................................................................... 13
Button Description ............................................................................................................................... 13
9.2.1 Power Button .......................................................................................................................... 13
9.2.2 Lock Button............................................................................................................................. 13
Operating Modes of the Kit .................................................................................................................. 14
9.3.1 Application Flow ..................................................................................................................... 14
9.3.2 Normal Mode .......................................................................................................................... 14
9.3.3 Mode Change ......................................................................................................................... 14
9.3.4 Settings Mode......................................................................................................................... 15
9.3.4.1 LED Brightness Adjustment .................................................................................... 15
9.3.4.2 Buzzer Volume Adjustment .................................................................................... 15
9.3
10 Schematic .................................................................................................................. 17
10.1
10.2
10.3
10.4
MCU and Sensor Configuration Section.............................................................................................. 17
LED, Buzzer, and Switch Section ........................................................................................................ 18
Power Supply Section ......................................................................................................................... 19
Sensor Board ...................................................................................................................................... 19
Main MCU PCB – Top Layer ............................................................................................................... 20
Main MCU PCB – Bottom Layer .......................................................................................................... 21
Sensor PCB – Top Layer .................................................................................................................... 22
Sensor PCB – Bottom Layer ............................................................................................................... 23
11 PCB Design ................................................................................................................ 20
11.1
11.2
11.3
11.4
12 Bill of Materials .......................................................................................................... 24
13 References ................................................................................................................. 25
14 Revision History ........................................................................................................ 26
2
SAM D20 QTouch Robustness Demo [USER GUIDE]
2
Atmel-42324A-SAM-D20-QTouch-Robustness-Demo_UserGuide_102014
1
Overview
This document describes the SAM D20 QTouch Robustness demo kit. The demo kit showcases both
self-capacitance (with springs) sensors and mutual-capacitance sensors running on the same Atmel SAM D20
microcontroller. The associated package for SAM D20 QTouch Robustness Demo contains the schematic,
Gerber, BoM, and firmware.
The demo kit consists of two different PCBs. The mutual capacitance sensors and LEDs are kept on the top PCB.
The self capacitance sensors and other electronics are kept on the bottom PCB. The PCBs are electrically
connected to each other by means of a flex cable. The PCBs are mechanically held by hex screw mount
standoffs. The front panel is pasted over the top sensor PCB.
The demo kit is designed to be used as a standalone unit with its own on-board microcontroller to evaluate the
noise immunity and moisture tolerance performance. The SAM D20 QTouch Robustness demo kit running its
associated firmware can pass Test Level 3 (10V
RMS
) of IEC/EN 61000-4-6 specifications for conducted immunity.
Figure 1-1.
Internal View of the Demo Kit
SAM D20 QTouch Robustness Demo [USER GUIDE]
Atmel-42324A-SAM-D20-QTouch-Robustness-Demo_UserGuide_102014
3 3
3
3.1
Pin Configuration
Mutual Capacitance Sensors
The demo kit has one slider and four buttons which are based on mutual-capacitance sensing technology. The
slider is composed of eight channels. There are eight X-lines and two Y-lines.
Table 3-1.
Pin Configuration of the Mutual Capacitance Sensors
MCU PIN #
17
18
19
20
25
26
27
28
15
16
MCU PIN NAME
PA08
PA09
PA10
PA11
PB12
PB13
PB14
PB15
PA06
PA07
FUNCTIONALITY
X0
X1
X2
X3
X12
X13
X14
X15
Y4
Y15
3.2
Self Capacitance Sensors
The demo kit has six buttons which are based on self capacitance sensing technology. Philipp Spring is used to
bridge the air gap between the PCB and front panel. The Philipp Spring design is patented by Atmel. The design
specification of the Philipp Spring can be obtained from Atmel.
Table 3-2.
Pin Configuration of the Self Capacitance Sensors
MCU PIN #
4
5
6
9
10
11
MCU PIN NAME
PA03
PB04
PB05
PB06
PB07
PB08
FUNCTIONALITY
Y1
Y10
Y11
Y12
Y13
Y14
SAM D20 QTouch Robustness Demo [USER GUIDE]
Atmel-42324A-SAM-D20-QTouch-Robustness-Demo_UserGuide_102014
5 5
Embedded System
京公网安备 11010802033920号
EEWORLD
