Atmel QTouch Library User Guide

More documents

Recommendations

Info

QMatrix charge transfer is labeled as the X line. The receiver electrode (or receive line) used forQMatrix charge transfer is labeled as the Y line.QMatrix circuits offer good immunity to moisture films, extreme levels of temperature stability,superb low power characteristics, and small IC package sizes for a given key count.Sensor schematics for a QMatrix acquisition method designAtmel MCUX0RX0Sensor0,0Sensors,X,YSensor0,m...XnRXnSensorn,0Sensorn,mRY0Y0A...YmARYmCS0...CSmY0BYmBTypical values:RX: 1kRY: 1kCS: 4.7nFRYB: 470k----------------------------------Port-pin count =n + (2 * m) + 2SMPVrefRYB0RYBmn – number of X linesm – number of Y lines----------------------------------Port requirements:X: Configurable I/O pinYA:Configurable I/O pin (*)YB: ADC port (*)SMP: Configurable I/O pinVref: AIN0 (Comparator)(*): The port I/O pin shouldbe in consecutive orderFigure 5-5 : Schematics for a QMatrix acquisition method designGlobal settings common to all sensors of a specific acquisition methodThe touch sensing using QTouch library could be fine tuned by using a number of configurablesettings. This section explains the settings that are common to all sensors of a specific acquisitionmethod like QMatrix or QTouch.For example, if recalibration threshold (one of the global settings) of QMatrix acquisition methodis set as 1, all QMatrix sensors will have recalibration threshold of 1.168207K-AT42-09/11
Recalibration ThresholdRecalibration threshold is the level above which automatic recalibration occurs. Recalibrationthreshold is expressed as a percentage of the detection threshold setting. This setting is anenumerated value and its settings are as follows:• Setting of 0 = 100% of detect threshold (RECAL_100)• Setting of 1 = 50% of detect threshold (RECAL_50)• Setting of 2 = 25% of detect threshold (RECAL_25)• Setting of 3 = 12.5% of detect threshold (RECAL_12_5)• Setting of 4 = 6.25% of detect threshold (RECAL_6_25)However, an absolute value of 4 is the hard limit for this setting. For example, if the detectionthreshold is say, 40 and the Recalibration threshold value is set to 4. This implies an absolutevalue of 2 (40 * 6.25% = 2.5), but this is hard limited to 4.Setting Variable name Data Type Unit Min Max TypicalRecalibration threshold qt_recal_threshold uint8_t Enum 4 Detect 1thresholdDetect IntegrationThe QTouch Library features a detect integration mechanism, which acts to confirm detection in arobust fashion. The detect integrator (DI) acts as a simple signal filter to suppress false detectionscaused by spurious events like electrical noise.A counter is incremented each time the sensor delta has exceeded its threshold and stayed therefor a specific number of acquisitions, without going below the threshold levels. When this counterreaches a preset limit (the DI value) the sensor is finally declared to be touched. If on anyacquisition the delta is not seen to exceed the threshold level, the counter is cleared and theprocess has to start from the beginning. The DI process is applicable to a ‘release’ (going out ofdetect) event as well.For example, if the DI value is 10, then the device has to exceed its threshold and stay there for10 acquisitions in succession without going below the threshold level, before the sensor isdeclared to be touched.Setting Variable name Data Type Unit Min Max TypicalDI qt_di uint8_t Cycles 0 255 4Drift Hold TimeDrift Hold Time (DHT) is used to restrict drift on all sensors while one or more sensors areactivated. It defines the length of time the drift is halted after a key detection.This feature is useful in cases of high density keypads where touching a key or floating a fingerover the keypad would cause untouched keys to drift, and therefore create a sensitivity shift, andultimately inhibit any touch detection.Setting Variable name Data Type Unit Min Max TypicalDrift hold time qt_drift_hold_time uint8_t 200 ms 1 255 20 (4s)17
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 12 and 13: • ARM: refers to a device in the
Page 14 and 15: Libraries for AVR microcontrollers
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
Page 60 and 61: Number ofchannels requiredfor the a
Page 62 and 63: 2. The above definitions should be
Page 64 and 65: NUM_Y_LINES_ROTOR_SLIDER_QT_MAX_NUM
Page 66 and 67:
has Four Comparators (AC0A , AC1A ,
Page 68 and 69:
Note: When using the IAR IDE / comp
Page 70 and 71:
Figure 5-11: Selecting the right co
Page 72 and 73:
SNS1 - SNSK1 & SNS2 -SNSK2QT_NUM_CH
Page 74 and 75:
Selecting the right configurationTh
Page 76 and 77:
Figure 5-20 : Specifying QMatrix ac
Page 78 and 79:
Debug Support in Example applicatio
Page 80 and 81:
Support for different compiler tool
Page 82 and 83:
Maximum number of rotor / sliders s
Page 84 and 85:
Tips on pin assignments for the sen
Page 86 and 87:
ATtiny88)v1g1s2(ATtiny461,ATmega16a
Page 88 and 89:
X0,X1,X2,X3 are on PB0,PB1,PB2,PB3N
Page 90 and 91:
1. The channel numbers are allocate
Page 92 and 93:
SNSK_array[1][1]=0x00; (SNSK odd ma
Page 94 and 95:
SNSK_array[1][0]=0x14; (SNSK even m
Page 96 and 97:
Figure 5-28: New Design Sensors in
Page 98 and 99:
Figure 5-31: Selecting the MCU for
Page 100 and 101:
Figure 5-34: Selecting the SNS and
Page 102 and 103:
2. QTOUCH_STUDIO_MASKS needs to be
Page 104 and 105:
Figure 5-38: Selecting New Design3.
Page 106 and 107:
Figure 5-42: Start window of the co
Page 108 and 109:
Figure 5-45: Selecting the X,YA,YB,
Page 110 and 111:
The code can be copied using the
Page 112 and 113:
ApplicablereleaseQTouch libraries v
Page 114 and 115:
Device Specific LibrariesIntroducti
Page 116 and 117:
Table 8 Compiler tool chains suppor
Page 118 and 119:
maintains the States of QMatrix, QT
Page 120 and 121:
equired as shown in the case A of F
Page 122 and 123:
Figure 37 QMatrix method schematicQ
Page 124 and 125:
Figure 39 QMatrix API Flow diagram
Page 126 and 127:
CAT Module Pin NameCSA0CSB0CSA1CSB1
Page 128 and 129:
The QTouch method acquisition using
Page 130 and 131:
Host Application codeUsing the init
Page 132 and 133:
Frozen Stop Stop Run Run Run Run On
Page 134 and 135:
Figure 45 Raw acquisition mode API
Page 136 and 137:
Figure 46 GNU Example project usage
Page 138 and 139:
the QTouch Library as QMatrix data
Page 140 and 141:
TOUCH_STATUS_CHANGE 0x0002u Status
Page 142 and 143:
sensor_type_tEnumerationUsesensor_t
Page 144 and 145:
OUT_OF_TOUCHIN_TOUCHCurrently the a
Page 146 and 147:
num_channel_signals uint8_t Length
Page 148 and 149:
touch_at_statusstructureInput / Out
Page 150 and 151:
UseData structure which holds the R
Page 152 and 153:
variable to the Touch library. The
Page 154 and 155:
structure.p_qta_config touch_qt_con
Page 156 and 157:
p_touch_sensor_param touch_qm_param
Page 158 and 159:
current_time_ms touch_time_t Curren
Page 160 and 161:
touch_ret_t touch_qt_sensor_config(
Page 162 and 163:
touch_qt_sensors_calibratetouch_ret
Page 164 and 165:
touch_qt_get_libinfotouch_ret_t tou
Page 166 and 167:
• This API updates the configurat
Page 168 and 169:
Rule Rule Description Advisory/Requ
Page 170 and 171:
VCCPA0No ConnectionPA1PA2ATtiny20PA
Page 172 and 173:
QTouch Library configuration parame
Page 174 and 175:
Recommended setting.Table 19 QTouch
Page 176 and 177:
Figure 51 Schematic overview of QTo
Page 178 and 179:
QTouch Library configuration parame
Page 180 and 181:
Devices supportedThe list of differ
Page 182 and 183:
• The channel number is derived f
Page 184 and 185:
MISRA Compliance ReportThis section
Page 186 and 187:
May 2010Ver 4.2July 2010Ver 4.3Jan
show all

Atmel QTouch Library User Guide

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?