This file contains the SAMD QTouch Library pin, register and sensors configuration options for Capacitive Touch acquisition using the PTC module.
Copyright (c) 2016-2018 Microchip Technology Inc. and its subsidiaries.
Macros | |
| #define | DEF_MUTLCAP_AUTO_OS AUTO_OS_DISABLE |
| Mutual Cap auto oversample setting. More... | |
| #define | DEF_MUTLCAP_CLK_PRESCALE PRSC_DIV_SEL_2 |
| Mutual cap PTC clock pre-scalar. More... | |
| #define | DEF_MUTLCAP_FILTER_LEVEL FILTER_LEVEL_32 /* Filter level */ |
| Mutual Cap filter level setting. More... | |
| #define | DEF_MUTLCAP_FREQ_MODE FREQ_MODE_NONE |
| Refer QTouch Library Peripheral Touch Controller User Guide for detailed information on tuning for Noise performance, touch response time and Power consumption. More... | |
| #define | DEF_MUTLCAP_GAIN_PER_NODE |
| Mutual Cap gain per touch channel. More... | |
| #define | DEF_MUTLCAP_HOP_FREQS FREQ_HOP_SEL_1,FREQ_HOP_SEL_2,FREQ_HOP_SEL_3 |
| PTC acquisition frequency delay setting. More... | |
| #define | DEF_MUTLCAP_NODES |
| Mutual Cap method touch channel nodes (GPIO pins) selected. More... | |
| #define | DEF_MUTLCAP_NUM_CHANNELS (10) /* Total number of channels */ |
| Mutual Cap number of channels. More... | |
| #define | DEF_MUTLCAP_NUM_ROTORS_SLIDERS (2) /* Number of rotor sliders */ |
| Mutual Cap number of Rotors and Sliders. More... | |
| #define | DEF_MUTLCAP_NUM_SENSORS (4) /* Total number of sensors */ |
| Mutual Cap number of Sensors. More... | |
| #define | DEF_MUTLCAP_SENSE_RESISTOR RSEL_VAL_100 |
| PTC series resistor setting. More... | |
| #define | DEF_TOUCH_MUTLCAP (1u) |
| Enable/Disable Self/Mutual Capacitance method. More... | |
| #define | DEF_TOUCH_PTC_ISR_LVL (1u) |
| PTC Module clock configuration. More... | |
| #define | DEF_TOUCH_SELFCAP (0u) |
Mutual Cap Global acquisition parameters. | |
Refer the Touch Library User guide for more information on these parameters. | |
| #define | DEF_TOUCH_MEASUREMENT_PERIOD_MS 20u |
| Mutual Cap Sensor measurement interval. More... | |
| #define | DEF_MUTLCAP_DI 4u |
| Mutual Cap Sensor detect integration (DI) limit. More... | |
| #define | DEF_MUTLCAP_TCH_DRIFT_RATE 20u |
| Mutual Cap Sensor towards touch drift rate. More... | |
| #define | DEF_MUTLCAP_ATCH_DRIFT_RATE 5u |
| Mutual Cap Sensor away from touch drift rate. More... | |
| #define | DEF_MUTLCAP_MAX_ON_DURATION 0u |
| Mutual Cap Sensor maximum ON time duration. More... | |
| #define | DEF_MUTLCAP_DRIFT_HOLD_TIME 20u |
| Mutual Cap Sensor drift hold time. More... | |
| #define | DEF_MUTLCAP_ATCH_RECAL_DELAY 10u |
| Mutual Cap Sensor away from touch recalibration delay. More... | |
| #define | DEF_MUTLCAP_ATCH_RECAL_THRESHOLD RECAL_100 |
| Mutual Cap Sensor away from touch recalibration threshold. More... | |
Mutual Cap Callback functions. | |
| #define | DEF_MUTLCAP_FILTER_CALLBACK (NULL) |
| Mutual Cap Filter callback function. More... | |
QDebug debug communication parameters. | |
| #define | DEF_TOUCH_QDEBUG_ENABLE_MUTLCAP |
| #define | DEF_TOUCH_QDEBUG_ENABLE 0u |
| #define DEF_MUTLCAP_ATCH_DRIFT_RATE 5u |
Mutual Cap Sensor away from touch drift rate.
Units: 200ms Default value: 5u = 1 second. Range: 1u to 127u.
| #define DEF_MUTLCAP_ATCH_RECAL_DELAY 10u |
Mutual Cap Sensor away from touch recalibration delay.
Default value: 10. Range: 1u to 255u.
| #define DEF_MUTLCAP_ATCH_RECAL_THRESHOLD RECAL_100 |
Mutual Cap Sensor away from touch recalibration threshold.
Default: RECAL_50 (recalibration threshold = 50% of detection threshold). Range: refer recal_threshold_t enum in touch_api_SAMD.h.
| #define DEF_MUTLCAP_AUTO_OS AUTO_OS_DISABLE |
Mutual Cap auto oversample setting.
Auto oversample controls the automatic oversampling of sensor channels when unstable signals are detected with the default setting of ‘Filter level’. Enabling Auto oversample results in 'Filter level' x 'Auto Oversample' number of samples taken on the corresponding sensor channel when an unstable signal is observed. In a case where ‘Filter level’ is set to FILTER_LEVEL_4 and ‘Auto Oversample’ is set to AUTO_OS_4, 4 oversamples are taken with stable signal values and 16 oversamples are taken when unstable signal is detected. Refer auto_os_t in touch_api_SAMD.h Range: AUTO_OS_DISABLE (oversample disabled) to AUTO_OS_128 (128 oversamples).
| #define DEF_MUTLCAP_CLK_PRESCALE PRSC_DIV_SEL_2 |
Mutual cap PTC clock pre-scalar.
PTC clock prescale setting. Refer touch_configure_ptc_clock() API in touch.c Example: if Generic clock input to PTC = 4MHz, then: PRSC_DIV_SEL_1 sets PTC Clock to 4MHz PRSC_DIV_SEL_2 sets PTC Clock to 2MHz PRSC_DIV_SEL_4 sets PTC Clock to 1MHz PRSC_DIV_SEL_8 sets PTC Clock to 500KHz
| #define DEF_MUTLCAP_DI 4u |
Mutual Cap Sensor detect integration (DI) limit.
Range: 0u to 255u.
| #define DEF_MUTLCAP_DRIFT_HOLD_TIME 20u |
Mutual Cap Sensor drift hold time.
Units: 200ms Default value: 20 (hold off drifting for 4 seconds after leaving detect). Range: 1u to 255u.
| #define DEF_MUTLCAP_FILTER_CALLBACK (NULL) |
Mutual Cap Filter callback function.
A filter callback (when not NULL) is called by the Touch Library each time a new set of Signal values are available. An Example filter callback function prototype. void qm_filter_callback( void );
| #define DEF_MUTLCAP_FILTER_LEVEL FILTER_LEVEL_32 /* Filter level */ |
Mutual Cap filter level setting.
The filter level setting controls the number of samples taken to resolve each acquisition. A higher filter level setting provides improved signal to noise ratio under noisy conditions, while increasing the total time for measurement resulting in increased power consumption and response time. Refer filter_level_t in touch_api_SAMD.h Range: FILTER_LEVEL_1 (one sample) to FILTER_LEVEL_64 ( 64 samples).
| #define DEF_MUTLCAP_FREQ_MODE FREQ_MODE_NONE |
Refer QTouch Library Peripheral Touch Controller User Guide for detailed information on tuning for Noise performance, touch response time and Power consumption.
For best noise performance, set -
For best power consumption, set -
FREQ_MODE_HOP: When frequency mode hopping option is selected, the PTC runs a frequency hopping cycle with subsequent measurements done using the three PTC acquisition frequency delay settings as specified in DEF_MUTLCAP_HOP_FREQS.
FREQ_MODE_SPREAD: When frequency mode spread spectrum option is selected, the PTC runs with spread spectrum enabled for jittered delay based acquisition.
FREQ_MODE_SPREAD_MEDIAN: When frequency mode spread spectrum median option is selected, the PTC runs with spread spectrum enabled. In this case, an additional software median filter is applied to the measured signal values.
FREQ_MODE_NONE: When frequency mode none option is selected, the PTC runs at constant speed. This mode is suited for best power consumption.
| #define DEF_MUTLCAP_GAIN_PER_NODE |
Mutual Cap gain per touch channel.
Gain is applied on a per-channel basis to allow a scaling-up of the touch sensitivity on contact. Note: delta on touch contact, not the resting signal which is measured on each sensor. Refer gain_t in touch_api_SAMD.h Range:GAIN_1 (no scaling) to GAIN_32 (scale-up by 32)
| #define DEF_MUTLCAP_HOP_FREQS FREQ_HOP_SEL_1,FREQ_HOP_SEL_2,FREQ_HOP_SEL_3 |
PTC acquisition frequency delay setting.
Specify three frequency hop delay settings.
The PTC acquisition frequency is dependent on the Generic clock input to PTC and PTC clock pre-scaler setting. This delay setting inserts "n" PTC clock cycles between consecutive measurements on a given sensor, thereby changing the PTC acquisition frequency. FREQ_HOP_SEL_1 setting inserts 0 PTC clock cycle between consecutive measurements. FREQ_HOP_SEL_16 setting inserts 15 PTC clock cycles. Hence, higher delay setting will increase the total time taken for capacitance measurement on a given sensor as compared to a lower delay setting.
A desired setting can be used to avoid noise around the same frequency as the acquisition frequency. Range: FREQ_HOP_SEL_1 to FREQ_HOP_SEL_16
| #define DEF_MUTLCAP_MAX_ON_DURATION 0u |
Mutual Cap Sensor maximum ON time duration.
Units: 200ms (Example: a value 5u indicated Max ON duration of 1 second.) Default value: 0 (No maximum ON time limit). Range: 0u to 255u.
| #define DEF_MUTLCAP_NODES |
Mutual Cap method touch channel nodes (GPIO pins) selected.
Mutual capacitance method use a pair of sensing electrodes for each touch channel. These are denoted as X and Y lines. Touch channel numbering follows the order in which X-Y nodes are specified. Capacitance measurement is done sequentially in the order in which touch channel nodes are specified.
| #define DEF_MUTLCAP_NUM_CHANNELS (10) /* Total number of channels */ |
Mutual Cap number of channels.
Specify the number of Mutual Cap touch channels to be used by the Touch Library. A key is formed used one touch channel. A rotor or slider can be formed using 3 to 8 touch channels. Range: 1u to 256u.
| #define DEF_MUTLCAP_NUM_ROTORS_SLIDERS (2) /* Number of rotor sliders */ |
Mutual Cap number of Rotors and Sliders.
Specify the total number of Mutual Cap Rotors and Sliders to be used by the Touch Library. The number of Rotors and Sliders mentioned here is part of the Total number of sensors specified in the QT_NUM_SENSORS macro. When no rotors or slider are required, specify a value of 0u. Range: 0u to 8u.
| #define DEF_MUTLCAP_NUM_SENSORS (4) /* Total number of sensors */ |
Mutual Cap number of Sensors.
Specify the number of Mutual Cap touch sensors to be used by the Touch Library. A sensor is either a key, rotor or slider. Example configuration: If the configuration has 6 keys (a key is formed using one X-Y node), one rotor (a Mutual Cap rotor is formed using 3 X-Y nodes) and one slider (a Mutual Cap slider is formed using 3 X-Y nodes), then the number of sensors is 6 key + 1 rotor + 1 slider = 8 sensors. Range: 1u to 256u.
| #define DEF_MUTLCAP_SENSE_RESISTOR RSEL_VAL_100 |
PTC series resistor setting.
For Mutual cap mode, this series resistor is switched internally on the Y-pin. For Self cap mode, the series resistor is switched internally on the Sensor pin.
Example: RSEL_VAL_0 sets internal series resistor to 0ohms. RSEL_VAL_20 sets internal series resistor to 20Kohms. RSEL_VAL_50 sets internal series resistor to 50Kohms. RSEL_VAL_100 sets internal series resistor to 100Kohms.
| #define DEF_MUTLCAP_TCH_DRIFT_RATE 20u |
Mutual Cap Sensor towards touch drift rate.
Units: 200ms Default value: 20 = 4 seconds. Range: 1u to 127u.
| #define DEF_TOUCH_MEASUREMENT_PERIOD_MS 20u |
Mutual Cap Sensor measurement interval.
Speicify period in milliseconds. Example, DEF_TOUCH_MEASUREMENT_PERIOD_MS 50u will perform measurement on touch sensors every 50msec.
Referenced by touch_sensors_init().
| #define DEF_TOUCH_MUTLCAP (1u) |
Enable/Disable Self/Mutual Capacitance method.
| #define DEF_TOUCH_PTC_ISR_LVL (1u) |
PTC Module clock configuration.
Before using the QTouch library API, the PTC module clock generator source should be configured appropriately. The PTC module clock can be generated using any of the eight generic clock generators (GCLK0-GCLK7). The associated generic clock multiplexer should be configured such that the PTC module clock is set to 4MHz. Refer touch_configure_ptc_clock API in touch.c for more information. PTC Module interrupt level. The Nested Vectored Interrupt Controller (NVIC) in the SAMD supports four different priority levels. The priority level of the PTC end of conversion ISR, used within QTouch library can be chosen based on application requirements in order to accommodate time critical operations. Range: 0u (Highest priority) to 3u (Lowest prioirity) For more details refer to the Cortex-M0 Technical Reference Manual.
| #define DEF_TOUCH_QDEBUG_ENABLE 0u |
| #define DEF_TOUCH_QDEBUG_ENABLE_MUTLCAP |
| #define DEF_TOUCH_SELFCAP (0u) |
1.8.5