ADC channel

Management and configuration functions for the individual ADC channels.

The API functions and definitions can be divided in two groups:

• channel management: direct access for getting conversion result.
• channel configuration: create/change configurations and write/read them to/from ADC channels.

Data Structures
struct	adc_channel_config
	ADC channel configuration. More...

Macros
#define	CONFIG_ADC_INTLVL   ADC_CH_INTLVL_LO_gc
	Default ADC channel interrupt level. More...

Enumerations
enum	adcch_mode {   ADCCH_MODE_COMPLETE = ADC_CH_INTMODE_COMPLETE_gc,   ADCCH_MODE_BELOW = ADC_CH_INTMODE_BELOW_gc,   ADCCH_MODE_ABOVE = ADC_CH_INTMODE_ABOVE_gc }
	ADC channel interrupt modes. More...
enum	adcch_negative_input {   ADCCH_NEG_PIN0,   ADCCH_NEG_PIN1,   ADCCH_NEG_PIN2,   ADCCH_NEG_PIN3,   ADCCH_NEG_PIN4,   ADCCH_NEG_PIN5,   ADCCH_NEG_PIN6,   ADCCH_NEG_PIN7,   ADCCH_NEG_PAD_GND,   ADCCH_NEG_INTERNAL_GND,   ADCCH_NEG_NONE }
	ADC channel negative input. More...
enum	adcch_positive_input {   ADCCH_POS_PIN0,   ADCCH_POS_PIN1,   ADCCH_POS_PIN2,   ADCCH_POS_PIN3,   ADCCH_POS_PIN4,   ADCCH_POS_PIN5,   ADCCH_POS_PIN6,   ADCCH_POS_PIN7,   ADCCH_POS_PIN8,   ADCCH_POS_PIN9,   ADCCH_POS_PIN10,   ADCCH_POS_PIN11,   ADCCH_POS_PIN12,   ADCCH_POS_PIN13,   ADCCH_POS_PIN14,   ADCCH_POS_PIN15,   ADCCH_POS_TEMPSENSE,   ADCCH_POS_BANDGAP,   ADCCH_POS_SCALED_VCC,   ADCCH_POS_DAC }
	ADC channel positive input. More...

ADC channel configuration
void	adcch_write_configuration (ADC_t *adc, uint8_t ch_mask, const struct adc_channel_config *ch_conf)
	Write configuration to ADC channel. More...
void	adcch_read_configuration (ADC_t *adc, uint8_t ch_mask, struct adc_channel_config *ch_conf)
	Read configuration from ADC channel. More...
static uint8_t	adcch_get_gain_setting (uint8_t gain)
	Get ADC channel setting for specified gain. More...
static void	adcch_set_input (struct adc_channel_config *ch_conf, enum adcch_positive_input pos, enum adcch_negative_input neg, uint8_t gain)
	Set ADC channel input mode, multiplexing and gain. More...
static void	adcch_set_pin_scan (struct adc_channel_config *ch_conf, uint8_t start_offset, uint8_t max_offset)
	Set ADC channel 0 pin scan. More...
static void	adcch_set_interrupt_mode (struct adc_channel_config *ch_conf, enum adcch_mode mode)
	Set ADC channel interrupt mode. More...
static void	adcch_enable_interrupt (struct adc_channel_config *ch_conf)
	Enable interrupts on ADC channel. More...
static void	adcch_disable_interrupt (struct adc_channel_config *ch_conf)
	Disable interrupts on ADC channel. More...
#define	ADCCH_FORCE_1X_GAINSTAGE   0xff
	Force enabling of gainstage with unity gain. More...

#define ADCCH_FORCE_1X_GAINSTAGE   0xff

Force enabling of gainstage with unity gain.

Referenced by adcch_get_gain_setting().

#define CONFIG_ADC_INTLVL   ADC_CH_INTLVL_LO_gc

Default ADC channel interrupt level.

Note

To override the channel interrupt level, define this symbol as the desired level in conf_adc.h.

Referenced by adcch_enable_interrupt().

enum adcch_mode

ADC channel interrupt modes.

Enumerator
ADCCH_MODE_COMPLETE	Set interrupt flag when conversions complete.
ADCCH_MODE_BELOW	Set interrupt flag when conversion result is below compare value.
ADCCH_MODE_ABOVE	Set interrupt flag when conversion result is above compare value.

enum adcch_negative_input

ADC channel negative input.

Identifies the signals that can be used as negative input to the ADC channels in differential mode. Some of the input signals are only available with certain gain settings, e.g., 1x gain.

Note

The ADC must be set in signed mode to use differential measurements. For single-ended measurements, ADDCH_NEG_NONE should be specified as negative input.

Pad and internal GND are not available on all devices. See the device manual for an overview of available input signals.

Enumerator
ADCCH_NEG_PIN0	ADC0 pin.
ADCCH_NEG_PIN1	ADC1 pin.
ADCCH_NEG_PIN2	ADC2 pin.
ADCCH_NEG_PIN3	ADC3 pin.
ADCCH_NEG_PIN4	ADC4 pin.
ADCCH_NEG_PIN5	ADC5 pin.
ADCCH_NEG_PIN6	ADC6 pin.
ADCCH_NEG_PIN7	ADC7 pin.
ADCCH_NEG_PAD_GND	PAD ground.
ADCCH_NEG_INTERNAL_GND	Internal ground.
ADCCH_NEG_NONE	Single ended mode.

enum adcch_positive_input

ADC channel positive input.

Identifies the external and internal signals that can be used as positive input to the ADC channels.

Enumerator
ADCCH_POS_PIN0
ADCCH_POS_PIN1
ADCCH_POS_PIN2
ADCCH_POS_PIN3
ADCCH_POS_PIN4
ADCCH_POS_PIN5
ADCCH_POS_PIN6
ADCCH_POS_PIN7
ADCCH_POS_PIN8
ADCCH_POS_PIN9
ADCCH_POS_PIN10
ADCCH_POS_PIN11
ADCCH_POS_PIN12
ADCCH_POS_PIN13
ADCCH_POS_PIN14
ADCCH_POS_PIN15
ADCCH_POS_TEMPSENSE	Temperature sensor.
ADCCH_POS_BANDGAP	Bandgap reference.
ADCCH_POS_SCALED_VCC	VCC scaled down by 10.
ADCCH_POS_DAC	DAC output.

static void adcch_disable_interrupt ( struct adc_channel_config *  ch_conf )

inlinestatic

Disable interrupts on ADC channel.

Parameters

ch_conf

Pointer to ADC channel configuration.

References adc_channel_config::intctrl.

Referenced by differential_signed_average(), main(), and single_ended_unsigned_average().

static void adcch_enable_interrupt ( struct adc_channel_config *  ch_conf )

inlinestatic

Enable interrupts on ADC channel.

Parameters

ch_conf

Pointer to ADC channel configuration.

References CONFIG_ADC_INTLVL, and adc_channel_config::intctrl.

Referenced by main().

static uint8_t adcch_get_gain_setting ( uint8_t  gain )

inlinestatic

Get ADC channel setting for specified gain.

Returns the setting that corresponds to specified gain.

Parameters

gain	Valid gain factor for the measurement.

Returns

Gain setting of type ADC_CH_GAIN_t.

References ADC_CH_GAIN_DIV2_gc, ADCCH_FORCE_1X_GAINSTAGE, and Assert.

Referenced by adcch_set_input().

void adcch_read_configuration	(	ADC_t *	adc,
		uint8_t	ch_mask,
		struct adc_channel_config *	ch_conf
	)

Read configuration from ADC channel.

Reads out the current configuration from the ADC channel to the specified buffer.

Parameters

adc	Pointer to ADC module.
ch_mask	Mask of ADC channel(s): ADC_CHn , where n specifies the channel. (Only a single channel can be given in mask)
ch_conf	Pointer to ADC channel configuration.

References ADC_CH0, adc_disable_clock(), adc_enable_clock(), adc_get_channel(), cpu_irq_restore(), cpu_irq_save(), adc_channel_config::ctrl, adc_channel_config::intctrl, adc_channel_config::muxctrl, and adc_channel_config::scan.

Referenced by main().

static void adcch_set_input ( struct adc_channel_config *  ch_conf, enum adcch_positive_input  pos, enum adcch_negative_input  neg, uint8_t  gain  )

inlinestatic

Set ADC channel input mode, multiplexing and gain.

Sets up an ADC channel's input mode and multiplexing according to specified input signals, as well as the gain.

Parameters

ch_conf	Pointer to ADC channel configuration.
pos	Positive input signal.
neg	Negative input signal: ADCCH_NEG_NONE for single-ended measurements. ADCCH_NEG_PINn , where n specifies a pin, for differential measurements. ADDCH_x_GND , where x specified pad or internal GND, for differential measurements.
gain	Gain factor for measurements: 1 for single-ended or differential with pin 0, 1, 2 or 3, pad or internal GND as negative input. 0 (0.5x), 1, 2, 4, 8, 16, 32 or 64 for differential with pin 4, 5, 6 or 7, pad or internal GND as negative input. ADCCH_FORCE_1X_GAINSTAGE to force the gain stage to be enabled with unity gain for differential measurement.

Note

The GND signals are not available on all devices. Refer to the device manual for information on available input signals.

With unity (1x) gain, some input selections may be possible both with and without the gain stage enabled. The driver will default to the configuration without gainstage to keep the current consumption as low as possible unless the user specifies ADCCH_FORCE_1X_GAINSTAGE as gain.

References ADC_CH_MUXNEG_MODE10_GND_gc, ADC_CH_MUXNEG_MODE10_INTGND_gc, ADC_CH_MUXNEG_MODE11_GND_gc, ADC_CH_MUXNEG_MODE11_INTGND_gc, adcch_get_gain_setting(), ADCCH_NEG_INTERNAL_GND, ADCCH_NEG_NONE, ADCCH_NEG_PAD_GND, ADCCH_NEG_PIN3, ADCCH_NEG_PIN4, ADCCH_NEG_PIN7, ADCCH_POS_TEMPSENSE, Assert, adc_channel_config::ctrl, and adc_channel_config::muxctrl.

Referenced by differential_signed_average(), main(), and single_ended_unsigned_average().

static void adcch_set_interrupt_mode ( struct adc_channel_config *  ch_conf, enum adcch_mode  mode  )

inlinestatic

Set ADC channel interrupt mode.

Parameters

ch_conf	Pointer to ADC channel configuration.
mode	Interrupt mode to set.

References adc_channel_config::intctrl.

Referenced by differential_signed_average(), main(), and single_ended_unsigned_average().

static void adcch_set_pin_scan ( struct adc_channel_config *  ch_conf, uint8_t  start_offset, uint8_t  max_offset  )

inlinestatic

Set ADC channel 0 pin scan.

Sets the parameters for pin scan, which enables measurements on multiple, successive input pins without any reconfiguration between conversions.

Pin scan works by adding a offset to the positive MUX setting to get the current input pin. The offset is incremented for each conversion, and is reset to 0 once a conversion with the maximum offset is done.

Parameters

ch_conf	Pointer to the ADC channel configuration structure
start_offset	Initial offset to start pin scan at 0 - max_offset
max_offset	Maximum offset for the pin scan 0 to disable 1 - 15 to enable

Note

Only the AVR XMEGA AU family features this setting.

Pin scan is only available on ADC channel 0.

References ADC_CH_OFFSET_gp, Assert, and adc_channel_config::scan.

void adcch_write_configuration	(	ADC_t *	adc,
		uint8_t	ch_mask,
		const struct adc_channel_config *	ch_conf
	)

Write configuration to ADC channel.

Writes the specified configuration to the ADC channel.

Parameters

adc	Pointer to ADC module.
ch_mask	Mask of ADC channel(s): ADC_CHn , where n specifies the channel. (Only a single channel can be given in mask)
ch_conf	Pointer to ADC channel configuration.

Note

The specified ADC's callback function must be set before this function is called if callbacks are enabled and interrupts are enabled in the channel configuration.

References ADC_CH0, adc_disable_clock(), adc_enable_clock(), adc_get_channel(), Assert, cpu_irq_restore(), cpu_irq_save(), adc_channel_config::ctrl, adc_channel_config::intctrl, adc_channel_config::muxctrl, and adc_channel_config::scan.

Referenced by differential_signed_average(), main(), and single_ended_unsigned_average().