Atmel QTouch Library User Guide

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• ARM: refers to a device in the ATSAM ARM® basedmicrocontroller family.• ATMEL QTouch Library: The combination of libraries for both touch sensing acquisitionmethods (QTouch and QMatrix).• QTouch Technology: A type of capacitive touch sensing technology using selfcapacitance - each channel has only one electrode.• QMatrix Technology: A type of capacitive touch sensing technology using mutualcapacitance – each channel has an drive electrode (X) and an receive electrode (Y).• Sensor: A channel or group of channels used to form a touch sensor. Sensors are of 3types (keys, rotors or sliders).• KEY: a single channel forms a single KEY type sensor, also known as a BUTTON• ROTOR, also known as a WHEEL, a group of channels forms a ROTOR sensor to detectangular position of touch.ooA Rotor is composed of 3 channels for a QTouch acquisition method.A Rotor can be composed of 3 to 8 channels for QMatrix acquisition method.• SLIDER, a group of channels forms a SLIDER sensor to detect the linear position oftouch.ooA Slider is composed of 3 channels for a QTouch acquisition method.A Slider can be composed of 3 to 8 channels for QMatrix acquisition method.• AKS: Adjacent Key Suppression. See Section 5.4.5• SNS PIN: Sense line for capacitive measurement using the QTouch Technology -connected to Cs.• SNSK PIN: Sense Key line for capacitive measurement using the QTouch Technology -connected to channel electrode through Rs.• X Line: The drive electrode (or drive line) used for QMatrix Technology.• Y Line: The receive electrode (or receive line) used for QMatrix Technology.• Port Pair: A combination of SNS port and SNSK port to which sensors are connected forQTouch technology. The SNS and SNSK ports used in a port pair can be located in thesame AVR Port (8 pins for 4 sensors), or they may be in different 2 different AVR Ports(8+8 pins for 8 sensors).• Charge Cycle Period: It is the width of the charging pulse applied to the channelcapacitor.• Dwell Cycle: In a QMatrix acquisition method, the duration in which charge coupled fromX to Y is captured.• Acquisition: A single capacitive measurement process.• Electrode: Electrodes are typically areas of copper on a printed circuit board but can alsobe areas of clear conductive indium tin oxide (ITO) on a glass or plastic touch screen.• Intra-port: A configuration for QTouch acquisition method libraries, when the sensor SNSand SNSK pins are available on the same port.• Inter-port: A configuration for QTouch acquisition method libraries, when the sensor SNSand SNSK pins are available on distinct ports.128207K-AT42-09/11
Generic QTouch LibrariesIntroductionATMEL QTouch provides a simple to use solution to realize touch sensing solutions on a range ofsupported ATMEL AVR Microcontrollers. The QTouch libraries provide support for both QTouchand QMatrix acquisition methods.Touch sensing using QMatrix or QTouch acquisition methods can be added to an application bylinking the appropriate ATMEL QTouch Library for the AVR Microcontroller and using a simple setof API to define the touch channels and sensors and then calling the touch sensing API’speriodically (or based on application needs) to retrieve the channel information and determinetouch sensor states.Figure 5-1 shows a typical configuration of channels when using an AVR and using the ATMELQTouch Library. The ATMEL QTouch Library has been added to a host application running on anAVR microcontroller. The sample configuration illustrates using the library that supports eighttouch channels numbered 0 to 7. The sensors are configured in the following order,• Sensor 0 on channels 0 to 2 have been configured as a rotor sensor.• Sensor 1 on channels 3 to 5 have been configured as a slider sensor.• Sensor 2 on channel 6 is configured as key sensor.• Sensor 3 on channel 7 is configured as key sensor.The host application uses the QTouch Library API’s to configure these channels and sensors,and to initiate detection of a touch using capacitive measurements.channel 0channel 1channel 2HostApplicationAtmel QTouchLibrarychannel 3channel 4sensor1sensor0channel 5channel 6sensor2channel 7sensor3Figure 5-1 : Typical interface of the ATMEL QTouch library with the host application.The QTouch libraries use minimal resources of the microcontroller. The sampling of the sensorsis controlled by the QTouch library, while the sampling period is controlled by the application(possibly using timers, sleep periods, varying the CPU clock, external events like interrupts orcommunications, etc).Acquisition MethodsThere are two methods available for touch acquisition namely1. QTouch acquisition method.2. QMatrix acquisition method.13
Page 1: Atmel QTouch LibraryUser GuideSuppo
Page 4: 5.6.11.6.1 Debug Support in the sam
Page 7 and 8: 6.3.16.21 touch_info_t ............
Page 14 and 15: Libraries for AVR microcontrollers
Page 16 and 17: QMatrix charge transfer is labeled
Page 18 and 19: Maximum ON DurationIf an object uni
Page 20 and 21: Setting Variable name Data Type Uni
Page 22 and 23: Guard ChannelGuard channel in Qtouc
Page 24 and 25: 7 AKS groups are supported by the l
Page 26 and 27: Data structuresThis section lists t
Page 28 and 29: The signal gain for each sensor is
Page 30 and 31: • This function can be called any
Page 32 and 33: unit16_t qt_measure_sensors( uint16
Page 34 and 35: Channel NumberingChannel numbering
Page 36 and 37: qt_reset_sensing()qt_enable_xxx()qt
Page 38 and 39: Port AAll SNSK pinsterminatedon thi
Page 40 and 41: Example:Pins A0 ,A3 and A5 of PORT
Page 42 and 43: Channel 47 N/A N/A N/A N/A N/A X7Y5
Page 44 and 45: channel 0channel 1channel 2channel
Page 46 and 47: Disabling and Enabling of Pull-up f
Page 48 and 49: ‣ Recommended threshold should be
Page 50 and 51: QMatrix acquisitionmethod libraries
Page 52 and 53: definition is not required.QT_NUM_C
Page 54 and 55: SNS1 and SNSK1 pins usethe same por
Page 56 and 57: • It is recommended to disable PU
Page 58 and 59: Table 4 :List of configurable param
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Number ofchannels requiredfor the a
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2. The above definitions should be
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NUM_Y_LINES_ROTOR_SLIDER_QT_MAX_NUM
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has Four Comparators (AC0A , AC1A ,
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Note: When using the IAR IDE / comp
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Figure 5-11: Selecting the right co
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SNS1 - SNSK1 & SNS2 -SNSK2QT_NUM_CH
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Selecting the right configurationTh
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Figure 5-20 : Specifying QMatrix ac
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Debug Support in Example applicatio
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Support for different compiler tool
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Maximum number of rotor / sliders s
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Tips on pin assignments for the sen
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ATtiny88)v1g1s2(ATtiny461,ATmega16a
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X0,X1,X2,X3 are on PB0,PB1,PB2,PB3N
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1. The channel numbers are allocate
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SNSK_array[1][1]=0x00; (SNSK odd ma
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SNSK_array[1][0]=0x14; (SNSK even m
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Figure 5-28: New Design Sensors in
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Figure 5-31: Selecting the MCU for
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Figure 5-34: Selecting the SNS and
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2. QTOUCH_STUDIO_MASKS needs to be
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Figure 5-38: Selecting New Design3.
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Figure 5-42: Start window of the co
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Figure 5-45: Selecting the X,YA,YB,
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The code can be copied using the
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ApplicablereleaseQTouch libraries v
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Device Specific LibrariesIntroducti
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Table 8 Compiler tool chains suppor
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maintains the States of QMatrix, QT
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equired as shown in the case A of F
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Figure 37 QMatrix method schematicQ
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Figure 39 QMatrix API Flow diagram
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CAT Module Pin NameCSA0CSB0CSA1CSB1
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The QTouch method acquisition using
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Host Application codeUsing the init
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Frozen Stop Stop Run Run Run Run On
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Figure 45 Raw acquisition mode API
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Figure 46 GNU Example project usage
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the QTouch Library as QMatrix data
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TOUCH_STATUS_CHANGE 0x0002u Status
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sensor_type_tEnumerationUsesensor_t
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OUT_OF_TOUCHIN_TOUCHCurrently the a
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num_channel_signals uint8_t Length
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touch_at_statusstructureInput / Out
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UseData structure which holds the R
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variable to the Touch library. The
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structure.p_qta_config touch_qt_con
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p_touch_sensor_param touch_qm_param
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current_time_ms touch_time_t Curren
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touch_ret_t touch_qt_sensor_config(
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touch_qt_sensors_calibratetouch_ret
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touch_qt_get_libinfotouch_ret_t tou
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• This API updates the configurat
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Rule Rule Description Advisory/Requ
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VCCPA0No ConnectionPA1PA2ATtiny20PA
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QTouch Library configuration parame
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Recommended setting.Table 19 QTouch
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Figure 51 Schematic overview of QTo
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QTouch Library configuration parame
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Devices supportedThe list of differ
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• The channel number is derived f
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MISRA Compliance ReportThis section
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May 2010Ver 4.2July 2010Ver 4.3Jan
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Atmel QTouch Library User Guide

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