CSLIB Capacitive Sensing Library#
Capacitive sensing firmware library for Silicon Labs MCUs.
Introduction#
The capacitive sensing library provides pre-compiled code set that performs touch qualification, filtering, and state maintanence for capacitive sensing-enabled Silicon Laboratories MCUs.
The library functions using calls into a device layer that interfaces with hardware peripherals.
Modules#
Enumerations#
Defines all noise characterization states the CSLIB will use for characterization.
Variables#
Global counter incremented by the system timer.
Stores interference characterization level, 0 being lowest and 3 being highest.
Sensor node data structure.
Bit that can be set to disable entrance to sleep, overriding timers.
Size of the sensor node struct, should only be changed at compile time by editing DEF_NUM_SENSORS.
Size of raw data buffers within sensor node struct elements, should not be changed.
Sets the number of consecutive values above/below threshold before button is qualified/disqualified.
Sets the scan period in ms for active mode scanning. Defaults to DEF_ACTIVE_MODE_PERIOD.
Describes average interference seen as a percentage of the average touch delta.
Sets the scan period in ms for sleep mode scanning. Defaults to DEF_ACTIVE_MODE_PERIOD.
Sets the number of consecutive scans without a single qualified touch before entering sleep mode.
Configures whether system goes to sleep between scans in active mode.
Sets whether the system is allowed to ever use sleep mode scanning.
Array storring percentages within touch deltas below which touch release events are qualified.
Array storring percentages within touch deltas below which touch events are qualified.
Array of expected conversion output codes between inactive and active sensor states.
Functions#
Checks to see if any enabled sensor is single active.
Checks if a sensor is single active.
Checks to see if any enabled sensor is debounce active.
Checks if a sensor is debounce active.
Pushes new sensor sample into sensor node buffer.
Reads a node structure sensor's raw buffer value.
Read touch delta from sensor node struct and expand from 8-bit value.
Resets an element of the sensor node struct back to defaults.
Initializes capacitive sensing-related peripherals.
Initializes capacitive sensing state variables.
Scans capacitive sensing inputs, processes and updates state variables.
Performs capacitive sensing conversion on a sensor.
Checks timing and possibly enters low power mode.
Checks timing and possibly enters low power mode.
Exits low power state for CSLIB.
Returns raw or filtered sensor data, based on characterized interference.
Get baseline-adjusted, noise-adjusted touch delta.
Callback to configure sensors for sleep mode.
Callback to confiure sensors for active mode.
Configure timer for sleep mode.
Callback to configure timer for active mode scanning.
Callback to enter low power mode.
Check wake sources.
Modify capacitive sense config for baseline initialization.
Restore capacitive sensing config to operational state.
Macros#
Defines the depth of the raw buffer. Note: this value should not be changed.
Bit that is set when sensor is qualified active.
Bit that is set when sensor is candidate active.
Enumeration Documentation#
CSLIB_noiseLevels#
CSLIB_noiseLevels
Defines all noise characterization states the CSLIB will use for characterization.
Enumerator | |
---|---|
low | Interference should have negligible impact on sensing. |
mid | Interference forces system to qualify touches conservatively. |
high | Interference forces entrance into no confidence mode if enabled. |
448
of file platform/middleware/cslib/inc/cslib.h
Variable Documentation#
timerTick#
uint8_t timerTick
Global counter incremented by the system timer.
391
of file platform/middleware/cslib/inc/cslib.h
noise_level#
uint8_t noise_level
Stores interference characterization level, 0 being lowest and 3 being highest.
394
of file platform/middleware/cslib/inc/cslib.h
CSLIB_node#
SensorStruct_t CSLIB_node[]
Sensor node data structure.
397
of file platform/middleware/cslib/inc/cslib.h
disable_sleep_and_stall#
uint8_t disable_sleep_and_stall
Bit that can be set to disable entrance to sleep, overriding timers.
400
of file platform/middleware/cslib/inc/cslib.h
CSLIB_numSensors#
uint8_t CSLIB_numSensors
Size of the sensor node struct, should only be changed at compile time by editing DEF_NUM_SENSORS.
403
of file platform/middleware/cslib/inc/cslib.h
CSLIB_sensorBufferSize#
uint8_t CSLIB_sensorBufferSize
Size of raw data buffers within sensor node struct elements, should not be changed.
406
of file platform/middleware/cslib/inc/cslib.h
CSLIB_buttonDebounce
uint8_t CSLIB_buttonDebounce
Sets the number of consecutive values above/below threshold before button is qualified/disqualified.
Defaults to DEF_BUTTON_DEBOUNCE
410
of file platform/middleware/cslib/inc/cslib.h
CSLIB_activeModePeriod#
uint16_t CSLIB_activeModePeriod
Sets the scan period in ms for active mode scanning. Defaults to DEF_ACTIVE_MODE_PERIOD.
413
of file platform/middleware/cslib/inc/cslib.h
CSLIB_systemNoiseAverage#
uint16_t CSLIB_systemNoiseAverage
Describes average interference seen as a percentage of the average touch delta.
100 would mean that average sample to sample interference is equal to the average touch delta configured in the system.
418
of file platform/middleware/cslib/inc/cslib.h
CSLIB_sleepModePeriod#
uint16_t CSLIB_sleepModePeriod
Sets the scan period in ms for sleep mode scanning. Defaults to DEF_ACTIVE_MODE_PERIOD.
421
of file platform/middleware/cslib/inc/cslib.h
CSLIB_countsBeforeSleep#
uint16_t CSLIB_countsBeforeSleep
Sets the number of consecutive scans without a single qualified touch before entering sleep mode.
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of file platform/middleware/cslib/inc/cslib.h
CSLIB_freeRunSetting#
uint8_t CSLIB_freeRunSetting
Configures whether system goes to sleep between scans in active mode.
1 means that the system is in free run mode and will not go to sleep. 0 means that the system will take a single scan within an active mode scan period and will then enter sleep once CSLIB_lowPowerUpdate() is called. The system will stay asleep until the next active mode scan period begins.
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of file platform/middleware/cslib/inc/cslib.h
CSLIB_sleepModeEnable#
uint8_t CSLIB_sleepModeEnable
Sets whether the system is allowed to ever use sleep mode scanning.
If set to 0, the system will always remain in active mode. If set to 1, the system is allowed to perform sleep mode scanning when conditions permit it.
436
of file platform/middleware/cslib/inc/cslib.h
CSLIB_inactiveThreshold#
const uint8_t CSLIB_inactiveThreshold[]
Array storring percentages within touch deltas below which touch release events are qualified.
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of file platform/middleware/cslib/inc/cslib.h
CSLIB_activeThreshold#
const uint8_t CSLIB_activeThreshold[]
Array storring percentages within touch deltas below which touch events are qualified.
442
of file platform/middleware/cslib/inc/cslib.h
CSLIB_averageTouchDelta#
const uint8_t CSLIB_averageTouchDelta[]
Array of expected conversion output codes between inactive and active sensor states.
445
of file platform/middleware/cslib/inc/cslib.h
Function Documentation#
CSLIB_anySensorSingleActive#
uint8_t CSLIB_anySensorSingleActive (void )
Checks to see if any enabled sensor is single active.
N/A |
This function checks the SINGLE_ACTIVE_MASK in the sensor node structure for all enabled sensors. If any sensor's SINGLE_ACTIVE_MASK is set, meaning that the sensor is a candidate active sensor, the the function returns TRUE. Otherwise it returns FALSE.
Returns
1 if any sensor is active, 0 otherwise
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of file platform/middleware/cslib/inc/cslib.h
CSLIB_isSensorSingleActive#
uint8_t CSLIB_isSensorSingleActive (uint8_t index)
Checks if a sensor is single active.
N/A | index | into sensor node element to be checked |
This checks to see if any enabled sensor is a candidate active sensor.
Returns
1 if element selected by index is single active, 0 otherwise
122
of file platform/middleware/cslib/inc/cslib.h
CSLIB_anySensorDebounceActive#
uint8_t CSLIB_anySensorDebounceActive (void )
Checks to see if any enabled sensor is debounce active.
N/A |
Checks to see if any enabled sensor is qualified active, meaning that the data from the sensor on this input has risen above the active threshold for a consecutive number of samples equaling at least the value defined by DEF_DEBOUNCE_COUNTS.
Returns
1 if any enabled sensor is debounce active, 0 otherwise
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of file platform/middleware/cslib/inc/cslib.h
CSLIB_isSensorDebounceActive#
uint8_t CSLIB_isSensorDebounceActive (uint8_t index)
Checks if a sensor is debounce active.
N/A | index | into sensor node element to be checked |
This checks to see if any enabled sensor is a qualified active sensor.
Returns
1 if element selected by index is debounce active, 0 otherwise
144
of file platform/middleware/cslib/inc/cslib.h
CSLIB_nodePushRaw#
void CSLIB_nodePushRaw (uint8_t index, uint32_t newValue)
Pushes new sensor sample into sensor node buffer.
N/A | index | index into sensor node array |
N/A | newValue | value to be pushed at index |
This function is used by the device layer of code that interfaces with capacitive sensing hardware. When CSLIB_update() calls into the device layer to convert a new sample set using CSLIB_scanSensorCB(), the device layer implementation of CSLIB_scanSensorCB should use this routine to push newly converted samples into the sensor node structure for processing within the library.
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of file platform/middleware/cslib/inc/cslib.h
CSLIB_nodeGetRaw#
uint16_t CSLIB_nodeGetRaw (uint8_t sensorIndex, uint8_t bufferIndex)
Reads a node structure sensor's raw buffer value.
N/A | sensorIndex | The element of the sensor node structure |
N/A | bufferIndex | The element inside the sensor node element's raw data buffer |
This function can be used to read values in the raw data buffer at bufferIndex of an enabled sensor specified by sensorIndex.
Note
sensorIndex should not exceed the value defined by CSLIB_numSensors
bufferIndex should not exceed the value defined by CSLIB_sensorBufferSize
Returns
the value in the raw data buffer
174
of file platform/middleware/cslib/inc/cslib.h
CSLIB_getUnpackedTouchDelta#
int16_t CSLIB_getUnpackedTouchDelta (uint8_t index)
Read touch delta from sensor node struct and expand from 8-bit value.
N/A | index | Designates the sensor touch delta to be read |
This function returns the 8-bit compressed touch delta as an uncompressed 16 bit value.
Returns
16-bit signed touch delta value of a sensor defined by index
185
of file platform/middleware/cslib/inc/cslib.h
CSLIB_resetSensorStruct#
void CSLIB_resetSensorStruct (uint8_t sensorIndex, uint16_t fillValue)
Resets an element of the sensor node struct back to defaults.
N/A | sensorIndex | index of sensor node struct to reset |
N/A | fillValue | value to be used when filling raw data buffer |
This function is called during initialization to reset the sensor at node sensorIndex back to back to its power-on state.
196
of file platform/middleware/cslib/inc/cslib.h
CSLIB_initHardware#
void CSLIB_initHardware (void )
Initializes capacitive sensing-related peripherals.
N/A |
This function calls into the library, which in turn calls into the device layer functions initializing the sensing and timing hardware used during capacitive sensing conversions.
206
of file platform/middleware/cslib/inc/cslib.h
CSLIB_initLibrary#
void CSLIB_initLibrary (void )
Initializes capacitive sensing state variables.
N/A |
This function resets all state variables in the sensor node struct and library-internal state variables to default.
215
of file platform/middleware/cslib/inc/cslib.h
CSLIB_update#
void CSLIB_update (void )
Scans capacitive sensing inputs, processes and updates state variables.
N/A |
This function should be called in a firmware project's main() loop. The function will execute a capacitive sensing scan sequence, filter samples, examine samples for qualified touches, and update other state variables.
225
of file platform/middleware/cslib/inc/cslib.h
CSLIB_scanSensorCB#
uint32_t CSLIB_scanSensorCB (uint8_t index)
Performs capacitive sensing conversion on a sensor.
N/A | index | The sensor to be scanned, corresponds to sensor node struct |
This device layer function is called from within library code after CSLIB_update() is called in the main loop. The function is responsible for any configuration of the capacitive sensing block necessary to perform the scan.
Returns
the newly converted capacitive sensing output
238
of file platform/middleware/cslib/inc/cslib.h
CSLIB_lowPowerUpdate#
void CSLIB_lowPowerUpdate (void )
Checks timing and possibly enters low power mode.
N/A |
This function checks the time in the system relative to active mode scan period timing. It should be called in the firmware project's main() while(1) loop.
If FREE_RUN_SETTING is set to 0, the function will enter low power until the next active mode scan period.
If FREE_RUN_SETTING is set to 1, the function will exit, allowing for another iteration in the main() loop.
If CSLIB_lowPowerUpdate() finds that no qualified touches have been found in a time specified by COUNTS_BEFORE_SLEEP multiplied by ACTIVE_MODE_SCAN_PERIOD, the function initializes the system to run in its sleep scanning mode and enters a low power state.
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of file platform/middleware/cslib/inc/cslib.h
CSLIB_lowPowerUpdateCheckAppBuilder#
void CSLIB_lowPowerUpdateCheckAppBuilder (void )
Checks timing and possibly enters low power mode.
N/A |
This function checks the time in the system relative to active mode scan period timing.
If CSLIB_lowPowerUpdate() finds that no qualified touches have been found in a time specified by COUNTS_BEFORE_SLEEP multiplied by ACTIVE_MODE_SCAN_PERIOD, the function initializes the system to run in its sleep scanning mode. The calling system stack will intiate low power entry.
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of file platform/middleware/cslib/inc/cslib.h
CSLIB_lowPowerUpdateExitAppBuilder#
void CSLIB_lowPowerUpdateExitAppBuilder (void )
Exits low power state for CSLIB.
N/A |
This function is called by the interface layer when it detects a threshold crossing interrupt. The function will return to normal CSLIB operation.
283
of file platform/middleware/cslib/inc/cslib.h
CSLIB_getNoiseAdjustedSensorData#
uint16_t CSLIB_getNoiseAdjustedSensorData (uint8_t index)
Returns raw or filtered sensor data, based on characterized interference.
N/A | index | Sensor node element whose data is to be read |
This function either returns the newest raw data for a sensor, or the newest filtered data for a sensor, depending on which data type the interference characterization algorithm determines to be necessary to show current sensor state. In low interference environments, raw data will be returned. In higher interference states, filtered data will be returned.
Returns
sensor data from sensor node struct defined index
298
of file platform/middleware/cslib/inc/cslib.h
CSLIB_getNormalizedDelta#
uint16_t CSLIB_getNormalizedDelta (uint8_t sensor_index, uint16_t flood_level)
Get baseline-adjusted, noise-adjusted touch delta.
N/A | sensor_index | Index into sensor node struct |
N/A | flood_level | additional value that can be subtracted in addition to baseline |
Returns value that is raw or filtered data minus the sensor's baseline. flood_level can be used to remove additional margin along with baseline.
Returns
Absolute delta between baseline and raw/filtered data
312
of file platform/middleware/cslib/inc/cslib.h
CSLIB_configureSensorForSleepModeCB#
void CSLIB_configureSensorForSleepModeCB (void )
Callback to configure sensors for sleep mode.
N/A |
Callback routine used if low power mode is included in build, this function configures the capacitive sensing block and inputs for sleep mode.
321
of file platform/middleware/cslib/inc/cslib.h
CSLIB_configureSensorForActiveModeCB#
void CSLIB_configureSensorForActiveModeCB (void )
Callback to confiure sensors for active mode.
N/A |
Callback routine to configure sensors for active mode scanning.
329
of file platform/middleware/cslib/inc/cslib.h
CSLIB_configureTimerForSleepModeCB#
void CSLIB_configureTimerForSleepModeCB (void )
Configure timer for sleep mode.
N/A |
If low power mode is included in build, this function sets the wake-up event to the sleep mode scan period.
338
of file platform/middleware/cslib/inc/cslib.h
CSLIB_configureTimerForActiveModeCB#
void CSLIB_configureTimerForActiveModeCB (void )
Callback to configure timer for active mode scanning.
N/A |
Configures the timer to initiate a scan as defined by active mode scan period.
346
of file platform/middleware/cslib/inc/cslib.h
CSLIB_enterLowPowerStateCB#
void CSLIB_enterLowPowerStateCB (void )
Callback to enter low power mode.
N/A |
If low power mode is included in build, this function mode-switches the core to a low power state.
355
of file platform/middleware/cslib/inc/cslib.h
CSLIB_checkTimerCB#
void CSLIB_checkTimerCB (void )
Check wake sources.
N/A |
This function examines the system timer to check for wake events.
This callback function examines the system timer to check for wake events.
363
of file platform/middleware/cslib/inc/cslib.h
CSLIB_baselineInitEnableCB#
void CSLIB_baselineInitEnableCB (void )
Modify capacitive sense config for baseline initialization.
N/A |
Saves configuration state and makes device-level modifications appropriate to baseline initialization using the CSLIB_scanSensorCB() function.
372
of file platform/middleware/cslib/inc/cslib.h
CSLIB_baselineInitDisableCB#
void CSLIB_baselineInitDisableCB (void )
Restore capacitive sensing config to operational state.
N/A |
This function reverts any baseline-related capactive sensing config.
380
of file platform/middleware/cslib/inc/cslib.h
Macro Definition Documentation#
DEF_SENSOR_BUFFER_SIZE#
#define DEF_SENSOR_BUFFER_SIZEValue:
2
Defines the depth of the raw buffer. Note: this value should not be changed.
65
of file platform/middleware/cslib/inc/cslib.h
DEBOUNCE_ACTIVE_MASK#
#define DEBOUNCE_ACTIVE_MASKValue:
0x80
Bit that is set when sensor is qualified active.
68
of file platform/middleware/cslib/inc/cslib.h
SINGLE_ACTIVE_MASK#
#define SINGLE_ACTIVE_MASKValue:
0x40
Bit that is set when sensor is candidate active.
71
of file platform/middleware/cslib/inc/cslib.h