ADC driver

Analog-to-Digital Converter (ADC) peripheral driver. More...

Modules
	ADC peripheral driver configuration

Data Structures
struct	nrfx_adc_done_evt_t
	ADC driver DONE event structure. More...
struct	nrfx_adc_sample_evt_t
	SAMPLE event structure. More...
struct	nrfx_adc_evt_t
	ADC driver event. More...
struct	nrfx_adc_channel_s
	ADC channel. More...
struct	nrfx_adc_config_t
	ADC configuration. More...

Macros
#define	NRFX_ADC_DEFAULT_CHANNEL(analog_input)
	Macro for initializing the ADC channel with the default configuration. More...
#define	NRFX_ADC_DEFAULT_CONFIG
	ADC default configuration. More...

Typedefs
typedef struct nrfx_adc_channel_s	nrfx_adc_channel_t
	Forward declaration of the nrfx_adc_channel_t type.
typedef void(*	nrfx_adc_event_handler_t )(nrfx_adc_evt_t const *p_event)
	User event handler prototype. More...

Enumerations
enum	nrfx_adc_evt_type_t {   NRFX_ADC_EVT_DONE,   NRFX_ADC_EVT_SAMPLE }
	Driver event types. More...

Functions
nrfx_err_t	nrfx_adc_init (nrfx_adc_config_t const *p_config, nrfx_adc_event_handler_t event_handler)
	Function for initializing the ADC. More...
void	nrfx_adc_uninit (void)
	Function for uninitializing the ADC. More...
void	nrfx_adc_channel_enable (nrfx_adc_channel_t *const p_channel)
	Function for enabling an ADC channel. More...
void	nrfx_adc_channel_disable (nrfx_adc_channel_t *const p_channel)
	Function for disabling an ADC channel. More...
void	nrfx_adc_all_channels_disable (void)
	Function for disabling all ADC channels. More...
void	nrfx_adc_sample (void)
	Function for starting ADC sampling. More...
nrfx_err_t	nrfx_adc_sample_convert (nrfx_adc_channel_t const *const p_channel, nrf_adc_value_t *p_value)
	Function for executing a single ADC conversion. More...
nrfx_err_t	nrfx_adc_buffer_convert (nrf_adc_value_t *buffer, uint16_t size)
	Function for converting data to the buffer. More...
bool	nrfx_adc_is_busy (void)
	Function for retrieving the ADC state. More...
__STATIC_INLINE uint32_t	nrfx_adc_start_task_get (void)
	Function for getting the address of the ADC START task. More...

Detailed Description

Analog-to-Digital Converter (ADC) peripheral driver.

Macro Definition Documentation

#define NRFX_ADC_DEFAULT_CHANNEL

(

analog_input

)

Value:

{ \
 NULL, \
 { \
 .resolution = NRF_ADC_CONFIG_RES_10BIT, \
 .scaling = NRF_ADC_CONFIG_SCALING_INPUT_FULL_SCALE, \
 .reference = NRF_ADC_CONFIG_REF_VBG, \
 .input = (analog_input), \
 .extref = NRF_ADC_CONFIG_EXTREFSEL_NONE \
 } \
 }

Macro for initializing the ADC channel with the default configuration.

#define NRFX_ADC_DEFAULT_CONFIG

Value:

{ \
 .interrupt_priority = NRFX_ADC_CONFIG_IRQ_PRIORITY \
}

ADC default configuration.

Typedef Documentation

typedef void(* nrfx_adc_event_handler_t)(nrfx_adc_evt_t const *p_event)

User event handler prototype.

This function is called when the requested number of samples has been processed.

Parameters

p_event

Event.

Enumeration Type Documentation

enum nrfx_adc_evt_type_t

Driver event types.

Enumerator
NRFX_ADC_EVT_DONE	Event generated when the buffer is filled with samples.
NRFX_ADC_EVT_SAMPLE	Event generated when the requested channel is sampled.

Function Documentation

void nrfx_adc_all_channels_disable

(

void

)

Function for disabling all ADC channels.

This function can be called only when there is no conversion in progress (the ADC is not busy).

nrfx_err_t nrfx_adc_buffer_convert	(	nrf_adc_value_t *	buffer,
		uint16_t	size
	)

Function for converting data to the buffer.

If the driver is initialized in non-blocking mode, this function returns when the first conversion is set up. When the buffer is filled, the application is notified by the event handler. If the driver is initialized in blocking mode, the function returns when the buffer is filled.

Conversion is done on all enabled channels, but it is not triggered by this function. This function will prepare the ADC for sampling and then wait for the SAMPLE task. Sampling can be triggered manually by the nrfx_adc_sample function or by PPI using the NRF_ADC_TASK_START task.

Note

If more than one channel is enabled, the function emulates scanning, and a single START task will trigger conversion on all enabled channels. For example: If 3 channels are enabled and the user requests 6 samples, the completion event handler will be called after 2 START tasks.

The application must adjust the sampling frequency. The maximum frequency depends on the sampling timer and the maximum latency of the ADC interrupt. If an interrupt is not handled before the next sampling is triggered, the sample will be lost.

Parameters

[in]	buffer	Result buffer.
[in]	size	Buffer size in samples.

Return values

NRFX_SUCCESS	Conversion was successful.
NRFX_ERROR_BUSY	The driver is busy.

void nrfx_adc_channel_disable

(

nrfx_adc_channel_t *const

p_channel

)

Function for disabling an ADC channel.

This function can be called only when there is no conversion in progress (the ADC is not busy).

Parameters

p_channel

Pointer to the channel instance.

void nrfx_adc_channel_enable

(

nrfx_adc_channel_t *const

p_channel

)

Function for enabling an ADC channel.

This function configures and enables the channel. When nrfx_adc_buffer_convert is called, all channels that have been enabled with this function are sampled.

This function can be called only when there is no conversion in progress (the ADC is not busy).

Note

The channel instance variable p_channel is used by the driver as an item in a list. Therefore, it cannot be an automatic variable that is located on the stack.

Parameters

[in]

p_channel

Pointer to the channel instance.

nrfx_err_t nrfx_adc_init	(	nrfx_adc_config_t const *	p_config,
		nrfx_adc_event_handler_t	event_handler
	)

Function for initializing the ADC.

If a valid event handler is provided, the driver is initialized in non-blocking mode. If event_handler is NULL, the driver works in blocking mode.

Parameters

[in]	p_config	Pointer to the structure with the initial configuration.
[in]	event_handler	Event handler provided by the user.

Return values

NRFX_SUCCESS	Initialization was successful.
NRFX_ERROR_INVALID_STATE	The driver is already initialized.

bool nrfx_adc_is_busy

(

void

)

Function for retrieving the ADC state.

Return values

true	The ADC is busy.
false	The ADC is ready.

void nrfx_adc_sample

(

void

)

Function for starting ADC sampling.

This function triggers single ADC sampling. If more than one channel is enabled, the driver emulates scanning and all channels are sampled in the order they were enabled.

nrfx_err_t nrfx_adc_sample_convert	(	nrfx_adc_channel_t const *const	p_channel,
		nrf_adc_value_t *	p_value
	)

Function for executing a single ADC conversion.

This function selects the desired input and starts a single conversion. If a valid pointer is provided for the result, the function blocks until the conversion is completed. Otherwise, the function returns when the conversion is started, and the result is provided in an event (driver must be initialized in non-blocking mode, otherwise an assertion will fail). The function will fail if ADC is busy. The channel does not need to be enabled to perform a single conversion.

Parameters

[in]	p_channel	Channel.
[out]	p_value	Pointer to the location where the result is to be placed. Unless NULL is provided, the function is blocking.

Return values

NRFX_SUCCESS	Conversion was successful.
NRFX_ERROR_BUSY	The ADC driver is busy.

__STATIC_INLINE uint32_t nrfx_adc_start_task_get

(

void

)

Function for getting the address of the ADC START task.

This function is used to get the address of the START task, which can be used to trigger ADC conversion.

Returns

Start task address.

void nrfx_adc_uninit

(

void

)

Function for uninitializing the ADC.

This function stops all ongoing conversions and disables all channels.