ADC¶

Analog to digital converters, typically used for measuring voltages for sensors, battery voltage, etc.

Defines¶

MIRA_ADC_PIN_VDD¶

#define MIRA_ADC_PIN_VDD

MIRA_ADC_PIN_DISABLED¶

#define MIRA_ADC_PIN_DISABLED

Types¶

mira_adc_value_t¶

typedef int16_t mira_adc_value_t;

Enums¶

mira_adc_reference_t¶

Name	Description
`MIRA_ADC_REF_VDD`
`MIRA_ADC_REF_INT_3_6V`

Structs¶

mira_adc_context_t¶

Struct containing the context of an ADC channel.

Do not change this struct directly, use the modifier methods mira_adc_set_*().

Name	Type	Description
`gpio_pin_p`	`uint16_t`
`gpio_pin_n`	`uint16_t`
`reference`	`mira_adc_reference_t`
`is_measuring`	`mira_bool_t`
`value`	`mira_adc_value_t`
`measuring_process`	`struct process *`

Functions¶

mira_adc_init¶

mira_status_t mira_adc_init(mira_adc_context_t *context);

Initialize the ADC module and an ADC context with default values.

Use this to set up the context block with default parameters and initialize the ADC module.

Parameters

Name	Description
context	Configuration block for the ADC.

Return value

Name	Description
MIRA_SUCCESS	The initialization was successful.

mira_adc_uninit¶

mira_status_t mira_adc_uninit(mira_adc_context_t *context);

Uninitialize the ADC module.

Uninitializes the ADC module and aborts on-going measurement.

Parameters

Name	Description
context	Configuration block for the ADC.

Return value

Name	Description
MIRA_SUCCESS	The initialization was successful.

mira_adc_set_source_supply¶

mira_status_t mira_adc_set_source_supply(mira_adc_context_t *context);

Set the source of the ADC to the supply voltage.

Parameters

Name	Description
context	Configuration block for the ADC.

Return value

Name	Description
MIRA_SUCCESS	The operation was successful.

mira_adc_set_source_single¶

mira_status_t mira_adc_set_source_single(mira_adc_context_t *context, mira_gpio_pin_t pin);

Set the source of the ADC to a single ended measurement.

Parameters

Name	Description
context	Configuration block for the ADC.
pin	GPIO pin for the source (not analog pin number).

Return value

Name	Description
MIRA_SUCCESS	The operation was successful. No error on wrong pin selection, mira_adc_measurement_start() detects that instead.

mira_adc_set_source_diff¶

mira_status_t mira_adc_set_source_diff(mira_adc_context_t *context, mira_gpio_pin_t pin_p, mira_gpio_pin_t pin_n);

Set the source of the ADC to a differential measurement.

If CPU doesn't support differential measurements, this will be emulated by two consecutive measurements.

Parameters

Name	Description
context	Configuration block for the ADC.
pin_p	GPIO pin for the positive source (not analog pin number).
pin_n	GPIO pin for the negative soruce (not analog pin number).

Return value

Name	Description
MIRA_SUCCESS	The operation was successful. No error on wrong pin selection, mira_adc_measurement_start() detects that instead.

mira_adc_set_reference¶

mira_status_t mira_adc_set_reference(mira_adc_context_t *context, mira_adc_reference_t reference);

Set the reference voltage of the analog conversion.

Sets the voltage that maps to the maximum voltage of the conversion.

Parameters

Name	Description
context	Configuration block for the ADC.
reference	The reference for the conversion.

Return value

Name	Description
MIRA_SUCCESS	The operation was successful.
MIRA_ERROR_NOT_SUPPORTED	The reference voltage is not supported by the device.

mira_adc_measurement_start¶

mira_status_t mira_adc_measurement_start(mira_adc_context_t *context);

Start a measurement.

mira_adc_measurement_in_progress() returns MIRA_FALSE when the measurement is finished.

Correct procedure for measurement:

mira_status_t status;
mira_value_t value;
status = mira_adc_measurement_start(&context);
if(status == MIRA_SUCCESS) {
    PROCESS_WAIT_UNTIL(!mira_adc_measurement_in_progress(&context));
    status = mira_adc_measurement_finish(&context, &value);
    ... measurement result and status ...
} else {
    ... handle error ...
}

Call mira_adc_measurement_finish() for every successful mira_adc_measurement_start() call.

Parameters

Name	Description
context	Configuration block for the ADC.

Return value

Name	Description
MIRA_SUCCESS	The operation was successful.
MIRA_ERROR_NOT_INITIALIZED	The ADC module is not initialized.
MIRA_ADC_ERROR_INVALID_PIN	A pin is invalid.
MIRA_ADC_ERROR_CHANNEL_BUSY	A measurement is already in progress.

mira_adc_measurement_in_progress¶

mira_bool_t mira_adc_measurement_in_progress(mira_adc_context_t *context);

Check if the measurement is in progress.

Parameters

Name	Description
context	Configuration block for the ADC.

Return value

Name	Description
MIRA_TRUE	A measurement is in progress.
MIRA_FALSE	No measurement is in progress.

mira_adc_measurement_finish¶

mira_status_t mira_adc_measurement_finish(mira_adc_context_t *context, mira_adc_value_t *value);

Finish the conversion and get the result.

Call this for each successful mira_adc_measurement_start() call, in order to free the ADC for other measurements.

Parameters

Name	Description
context	Configuration block for the ADC.
value	Storage of the measurement value. Only set if successful.

Return value

Name	Description
MIRA_SUCCESS	The operation was successful.
MIRA_ADC_ERROR_NO_MEASUREMENT	Measurement failed to start.