ADC tasks

Internal Analog-to-digital converter control. More...

Files
file	ruuvi_task_adc.c
file	ruuvi_task_adc.h

Enumerations
enum	rt_adc_mode_t { RATIOMETRIC , ABSOLUTE }

Functions
rd_status_t	rt_adc_init (void)
	Reserve ADC. More...
rd_status_t	rt_adc_uninit (void)
	Uninitialize ADC to release it for other users. More...
bool	rt_adc_is_init (void)
	Check if ADC is initialized. More...
rd_status_t	rt_adc_configure_se (rd_sensor_configuration_t *const config, const uint8_t handle, const rt_adc_mode_t mode)
	Configure ADC before sampling. More...
rd_status_t	rt_adc_sample (void)
	Take a new sample on ADC configured in single-shot/sleep mode. More...
rd_status_t	rt_adc_voltage_get (rd_sensor_data_t *const data)
	Populate data with latest sample. More...
rd_status_t	rt_adc_ratio_get (rd_sensor_data_t *const data)
	Populate data with latest ratiometric value. More...
rd_status_t	rt_adc_vdd_prepare (rd_sensor_configuration_t *const vdd_adc_configuration)
	Prepare for sampling VDD. More...
rd_status_t	rt_adc_vdd_sample (void)
	Sample VDD. More...
rd_status_t	rt_adc_vdd_get (float *const vdd)
	Get VDD. More...
rd_status_t	rt_adc_absolute_sample (rd_sensor_configuration_t *const configuration, const uint8_t handle, float *const sample)
	Get absolute Voltage Sample from selected ADC handle. More...
rd_status_t	rt_adc_ratiometric_sample (rd_sensor_configuration_t *const configuration, const uint8_t handle, float *const sample)
	Get ratiometric VDD Sample from selected ADC handle. More...

Detailed Description

Internal Analog-to-digital converter control.

Enumeration Type Documentation

rt_adc_mode_t

enum rt_adc_mode_t

Enumerator
RATIOMETRIC	ADC compares value to VDD.
ABSOLUTE	ADC measures absolute voltage in volts.

Definition at line 59 of file ruuvi_task_adc.h.

Function Documentation

rt_adc_absolute_sample()

rd_status_t rt_adc_absolute_sample	(	rd_sensor_configuration_t *const	configuration,
		const uint8_t	handle,
		float *const	sample
	)

Get absolute Voltage Sample from selected ADC handle.

This function initializes ADC, reads absolute voltage sample from selected handle. The parameter sample is absolute voltage relative to the device ground.

Parameters

[in]	configuration	Configuration of ADC.
[in]	handle	Handle to ADC, i.e. ADC pin.
[in]	sample	Pointer to a Voltage Sample.

Return values

RD_SUCCESS	on success
error	code from stack on error.

rt_adc_configure_se()

rd_status_t rt_adc_configure_se	(	rd_sensor_configuration_t *const	config,
		const uint8_t	handle,
		const rt_adc_mode_t	mode
	)

Configure ADC before sampling.

This function readies the ADC for sampling. Configuring the ADC may take some time (< 1 ms) while actual sample must be as fast as possible to catch transients.

Note: ADC should be configured to sleep or continuous mode. To take a single sample, call rt_adc_sample after configuration. Configuring ADC into single sample mode is equivalent to calling rt_adc_sample and configuring ADC into sleep immediately.

Parameters

[in,out]	config	Configuration of ADC.
[in]	handle	Handle to ADC, i.e. ADC pin.
[in]	mode	sampling mode, rt_adc_mode_t.

Return values

RD_SUCCESS	on success.
RD_ERROR_INVALID_STATE	if ADC is not initialized or if it is already configured.

rt_adc_init()

rd_status_t rt_adc_init

(

void

)

Reserve ADC.

Return values

RD_SUCCESS	on success.
RD_ERROR_INVALID_STATE	if ADC is already initialized.

rt_adc_is_init()

bool rt_adc_is_init

(

void

)

Check if ADC is initialized.

Return values

true	if ADC is initialized.
false	if ADC is not initialized.

rt_adc_ratio_get()

rd_status_t rt_adc_ratio_get

(

rd_sensor_data_t *const

data

)

Populate data with latest ratiometric value.

The data is ratio between 0.0 (gnd) and 1.0 (VDD). However the implementation is allowed to return negative values and values higher than 1.0 if the real voltage is beyond the supply rails or if differential sample is negative.

Parameters

[in]

data

Data which has a field for ratiometric ADC value

Return values

RD_SUCCESS	on success
RD_ERROR_INVALID_STATE	if ADC is not initialized or configured.
error	code from stack on error.

rt_adc_ratiometric_sample()

rd_status_t rt_adc_ratiometric_sample	(	rd_sensor_configuration_t *const	configuration,
		const uint8_t	handle,
		float *const	sample
	)

Get ratiometric VDD Sample from selected ADC handle.

This function initializes ADC, reads ratiometric voltage sample from selected handle. The parameter sample is a ration of voltage pin, relative to VDD, varying between 0.0 (GND) and 1.0 (VDD). Additionally the parameter sample could be outside limits as described in rt_adc_ratio_get.

Parameters

[in]	configuration	Configuration of ADC.
[in]	handle	Handle to ADC, i.e. ADC pin.
[in]	sample	Pointer to a Voltage Sample.

Return values

RD_SUCCESS	on success
error	code from stack on error.

rt_adc_sample()

rd_status_t rt_adc_sample

(

void

)

Take a new sample on ADC configured in single-shot/sleep mode.

If this function returns RD_SUCCESS new sample can be immediately read with rt_adc_voltage_get or rt_adc_ratio_get

Return values

RD_SUCCESS	Sampling was successful
RD_ERROR_INVALID_STATE	ADC is not initialized or configured

rt_adc_uninit()

rd_status_t rt_adc_uninit

(

void

)

Uninitialize ADC to release it for other users.

Return values

RD_SUCCESS	on success.
RD_ERROR_FATAL	if ADC lock can't be released. Reboot.

rt_adc_vdd_get()

rd_status_t rt_adc_vdd_get

(

float *const

vdd

)

Get VDD.

This function should be called any time after rt_adc_vdd_sample. The value returned will remain fixed until next call to rt_adc_vdd_sample.

Parameters

[out]

vdd

VDD voltage in volts.

Return values

RD_SUCCESS	on success
RD_ERROR_INVALID_STATE	if rt_adc_vdd_sample wasn't called.

rt_adc_vdd_prepare()

rd_status_t rt_adc_vdd_prepare

(

rd_sensor_configuration_t *const

vdd_adc_configuration

)

Prepare for sampling VDD.

This function should be called before entering energy intensive activity, such as using radio to transmit data. After calling this function ADC is primed for measuring the voltage droop of battery. On ADC configuration error, uninitialize ADC.

Return values

RD_SUCCESS	on success
RD_ERROR_INVALID_STATE	if ADC is already initialized.

rt_adc_vdd_sample()

rd_status_t rt_adc_vdd_sample

(

void

)

Sample VDD.

This function should be called as soon as possible after energy intensive activity. After a successful call value returned by rt_adc_vdd_get is updated and ADC is released.

Return values

RD_SUCCESS	on success
RD_ERROR_INVALID_STATE	if rt_adc_vdd_prepare wasn't called.

rt_adc_voltage_get()

rd_status_t rt_adc_voltage_get

(

rd_sensor_data_t *const

data

)

Populate data with latest sample.

The data is absolute voltage relative to device ground.

Parameters

[in]

data

Data which has a field for absolute ADC value

Return values

RD_SUCCESS	on success
RD_ERROR_INVALID_STATE	if ADC is not initialized or configured.
error	code from stack on error.