FREQM

FREQM peripheral driver interface. More...

Detailed Description

FREQM peripheral driver interface.

This interface allows to configure and use the Frequency Meter (FREQM) peripheral.

The Frequency Meter uses the frequency of a known reference clock to determine the frequency of a signal connected via GPIO.

Files
file	freqm.h
	FREQM peripheral driver interface definitions.

Typedefs
typedef void(*	freqm_cb_t) (uint32_t result, bool overflow, void *context)
	Frequency meter callback function. More...
typedef uint_fast8_t	freqm_t
	Define default Frequency meter type identifier.

Functions
void	freqm_init (freqm_t idx)
	Initialize the frequency meter. More...
void	freqm_frequency_get_async (freqm_t idx, freqm_cb_t freqm_cb, void *context, uint32_t period_us)
	Read number of periods of measured clock and calculate its frequency. More...
int	freqm_frequency_get (freqm_t idx, uint32_t *result, uint32_t period_us)
	Read number of periods of measured clock and calculate its frequency. More...

Typedef Documentation

freqm_cb_t

typedef void(* freqm_cb_t) (uint32_t result, bool overflow, void *context)

Frequency meter callback function.

When a measurement is done the callbackfunction is called.

Parameters

result	measured frequency in hz
overflow	overflow in sticky counter
context	pointer to user defined context data

Definition at line 49 of file freqm.h.

Function Documentation

freqm_frequency_get()

int freqm_frequency_get	(	freqm_t	idx,
		uint32_t *	result,
		uint32_t	period_us
	)

Read number of periods of measured clock and calculate its frequency.

This function uses a blocking mutex to wait for the measurement to finish.

Parameters

[in]	idx	index of the configuration
[out]	result	calculated frequency
[in]	period_us	measurement duration in microseconds

Returns

-EOVERFLOW if FREQM sticky counter has an overflow

0 on success

freqm_frequency_get_async()

void freqm_frequency_get_async	(	freqm_t	idx,
		freqm_cb_t	freqm_cb,
		void *	context,
		uint32_t	period_us
	)

Read number of periods of measured clock and calculate its frequency.

This function returns after triggering the measurement and calls freqm_callback , with the calculated result and context , when the measurement is done.

Parameters

[in]	idx	index of the configuration
[in]	freqm_cb	callback function when measurement is ready
[in]	context	context for the callback function
[in]	period_us	measurement duration in microseconds

freqm_init()

void freqm_init

(

freqm_t

idx

)

Initialize the frequency meter.

Parameters

[in]

idx

index of the configuration