LESENSE - Low Energy Sensor

Initialize the LESENSE module.

This function configures the main parameters of the LESENSE interface. See the initialization parameter type definition (LESENSE_Init_TypeDef) for more details.

Note

LESENSE_Init() is designed to initialize LESENSE once in an operation cycle. Be aware of the effects of reconfiguration if using this function from multiple sources in your code. This function has not been designed to be re-entrant. Requesting reset by setting reqReset to true is required in each reset or power-on cycle to configure the default values of the RAM mapped LESENSE registers. Notice that GPIO pins used by the LESENSE module must be properly configured by the user explicitly for the LESENSE to work as intended. (When configuring pins, one should remember to consider the sequence of configuration to avoid unintended pulses/glitches on output pins.)

Parameters

[in]	init	The LESENSE initialization structure.
[in]	reqReset	Request to call LESENSE_Reset() first to initialize all LESENSE registers with default values.

Set the scan frequency for periodic scanning.

This function only applies to LESENSE if a period counter is used as a trigger for scan start. The calculation is based on the following formula: Fscan = LFACLKles / ((1+PCTOP)*2^PCPRESC)

Note

Note that the calculation does not necessarily result in the requested scan frequency due to integer division. Check the return value for the resulted scan frequency.

Parameters

[in]	refFreq	Select reference LFACLK clock frequency in Hz. If set to 0, the current clock frequency is being used as a reference.
[in]	scanFreq	Set the desired scan frequency in Hz.

Returns

Frequency in Hz calculated and set by this function. Users can use this to compare the requested and set values.

Set scan mode of the LESENSE channels.

This function configures how the scan start is triggered. It can be used for re-configuring the scan mode while running the application but it is also used by LESENSE_Init() for initialization.

Note

Users can configure the scan mode by LESENSE_Init() function, but only with a significant overhead. This simple function serves the purpose of controlling this parameter after the channel has been configured. Be aware of the effects of the non-atomic Read-Modify-Write cycle.

Parameters

[in]	scanMode	Select the location to map LESENSE alternate excitation channels. lesenseScanStartPeriodic - A new scan is started each time the period counter overflows. lesenseScanStartOneShot - A single scan is performed when LESENSE_ScanStart() is called. lesenseScanStartPRS - A new scan is triggered by pulse on the PRS channel.
[in]	start	If true, LESENSE_ScanStart() is immediately issued after configuration.

Set the start delay of the sensor interaction on each channel.

This function sets the start delay of the sensor interaction on each channel. It can be used for adjusting the start delay while running the application but it is also used by LESENSE_Init() for initialization.

Note

Users can configure the start delay by LESENSE_Init() function, but only with a significant overhead. This simple function serves the purpose of controlling this parameter after the channel has been configured. Be aware of the effects of the non-atomic Read-Modify-Write cycle.

Parameters

[in]

startDelay

A number of LFACLK cycles to delay. A valid range: 0-3 (2 bit).

Set the clock division for LESENSE timers.

Use this function to configure the clock division for the LESENSE timers used for excitation timing. The division setting is global but the clock source can be selected for each channel using LESENSE_ChannelConfig() function. See documentation for more details.

Note

If AUXHFRCO is used for excitation timing, LFACLK can't exceed 500 kHz. LFACLK can't exceed 50 kHz if the ACMP threshold level (ACMPTHRES) is not equal for all channels.

Parameters

[in]	clk	Select the clock to prescale. lesenseClkHF - set AUXHFRCO clock divisor for HF timer. lesenseClkLF - set LFACLKles clock divisor for LF timer.
[in]	clkDiv	The clock divisor value. A valid range depends on the clk value.