ADC¶

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

Defines¶

Name	Value	Description
`MIRA_ADC_PIN_VDD`	0xFF00
`MIRA_ADC_PIN_DISABLED`	0xFF01

Types¶

Name	Type	Description
`mira_adc_value_t`	`int16_t`

Enums¶

mira_adc_reference_t¶

Name	Value	Description
`MIRA_ADC_REF_VDD`
`MIRA_ADC_REF_INT_3_6V`

Structs¶

mira_adc_context_t¶

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

Struct containing the context of an ADC channel.

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

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

Parameter	Description
`context`	Configuration block for the ADC.

Return

Status of the operation.

Value	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

Parameter	Description
`context`	Configuration block for the ADC.

Return

Status of the operation.

Value	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

Parameter	Description
`context`	Configuration block for the ADC.

Return

Status of the operation.

Value	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

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

Return

Status of the operation.

Value	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

Parameter	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

Status of the operation.

Value	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

Parameter	Description
`context`	Configuration block for the ADC.
`reference`	The reference for the conversion.

Return

Status of the operation.

Value	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.

Return

mira_status_t

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

Parameter	Description
`context`	Configuration block for the ADC.

Return

Status of the operation.

Value	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

Parameter	Description
`context`	Configuration block for the ADC.

Return

Status of measurement.

Value	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

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

Return

Status of the operation.

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