DAC

Interfaces for Digital-to-Analog Converters. More...

Topics
	Device-specific DAC API extensions

Files
file	dac.h
	Main header file for DAC (Digital-to-Analog Converter) driver API.

Data Structures
struct	dac_channel_cfg
	Structure for specifying the configuration of a DAC channel. More...
struct	dac_dt_spec
	Container for DAC channel information specified in devicetree. More...

Macros
#define	DAC_CHANNEL_BROADCAST   0xFF
	Broadcast channel identifier for DACs that support it.
#define	DAC_CHANNEL_CFG_DT(node_id)
	Get DAC channel configuration from a given devicetree node.
#define	DAC_DT_SPEC_GET_BY_NAME(node_id, name)
	Get DAC io-channel information from devicetree by name.
#define	DAC_DT_SPEC_GET_BY_NAME_OR(node_id, name, default_value)
	Like DAC_DT_SPEC_GET_BY_NAME(), with a fallback to a default value.
#define	DAC_DT_SPEC_INST_GET_BY_NAME(inst, name)
	Get DAC io-channel information from a DT_DRV_COMPAT devicetree instance by name.
#define	DAC_DT_SPEC_INST_GET_BY_NAME_OR(inst, name, default_value)
	Like DAC_DT_SPEC_INST_GET_BY_NAME(), with a fallback to a default value.
#define	DAC_DT_SPEC_GET_BY_IDX(node_id, idx)
	Get DAC io-channel information from devicetree.
#define	DAC_DT_SPEC_GET_BY_IDX_OR(node_id, idx, default_value)
	Like DAC_DT_SPEC_GET_BY_IDX(), with a fallback to a default value.
#define	DAC_DT_SPEC_INST_GET_BY_IDX(inst, idx)
	Get DAC io-channel information from a DT_DRV_COMPAT devicetree instance.
#define	DAC_DT_SPEC_INST_GET_BY_IDX_OR(inst, idx, default_value)
	Like DAC_DT_SPEC_INST_GET_BY_IDX(), with a fallback to a default value.
#define	DAC_DT_SPEC_GET(node_id)
	Equivalent to DAC_DT_SPEC_GET_BY_IDX(node_id, 0).
#define	DAC_DT_SPEC_GET_OR(node_id, default_value)
	Equivalent to DAC_DT_SPEC_GET_BY_IDX_OR(node_id, 0, default_value).
#define	DAC_DT_SPEC_INST_GET(inst)
	Equivalent to DAC_DT_SPEC_INST_GET_BY_IDX(inst, 0).
#define	DAC_DT_SPEC_INST_GET_OR(inst, default_value)
	Equivalent to DAC_DT_SPEC_INST_GET_BY_IDX_OR(inst, 0, default).

Typedefs
typedef int(*	dac_x_to_raw_fn) (uint32_t ref_mv, uint8_t resolution, uint32_t *valp)
	Conversion from specified input units to raw DAC units.

Functions
int	dac_channel_setup (const struct device *dev, const struct dac_channel_cfg *channel_cfg)
	Configure a DAC channel.
static int	dac_channel_setup_dt (const struct dac_dt_spec *spec)
	Configure an DAC channel from a struct dac_dt_spec.
int	dac_write_value (const struct device *dev, uint8_t channel, uint32_t value)
	Write a single value to a DAC channel.
static int	dac_write_value_dt (const struct dac_dt_spec *spec, uint32_t value)
	Write a single value to a DAC channel from a struct dac_dt_spec.
static int	dac_millivolts_to_raw (uint32_t ref_mv, uint8_t resolution, uint32_t *valp)
	Convert a millivolts value to a raw DAC value.
static int	dac_microvolts_to_raw (uint32_t ref_mv, uint8_t resolution, uint32_t *valp)
	Convert a raw DAC value to microvolts.
static int	dac_x_to_raw_dt_chan (dac_x_to_raw_fn conv_func, const struct dac_dt_spec *spec, uint32_t *valp)
	Convert a raw DAC value to an arbitrary output unit.
static int	dac_millivolts_to_raw_dt (const struct dac_dt_spec *spec, uint32_t *valp)
	Convert a millivolts value to raw DAC using information stored in a struct dac_dt_spec.
static int	dac_microvolts_to_raw_dt (const struct dac_dt_spec *spec, uint32_t *valp)
	Convert a microvolts value to raw DAC value using information stored in a struct dac_dt_spec.
static bool	dac_is_ready_dt (const struct dac_dt_spec *spec)
	Validate that the DAC device is ready.

Detailed Description

Interfaces for Digital-to-Analog Converters.

Since

2.3

Version

1.1.0

Macro Definition Documentation

DAC_CHANNEL_BROADCAST

#define DAC_CHANNEL_BROADCAST   0xFF

#include <zephyr/drivers/dac.h>

Broadcast channel identifier for DACs that support it.

Note

Only for use in dac_write_value().

DAC_CHANNEL_CFG_DT

#define DAC_CHANNEL_CFG_DT

(

node_id

)

#include <zephyr/drivers/dac.h>

Value:

        { \
        .resolution       = DT_PROP_OR(node_id, zephyr_resolution, 0), \
        .buffered         = DT_PROP(node_id, zephyr_buffered),         \
        .internal         = DT_PROP(node_id, zephyr_internal),         \
        .channel_id       = DT_REG_ADDR(node_id),                      \
}

Get DAC channel configuration from a given devicetree node.

This returns a static initializer for a struct dac_channel_cfg filled with data from a given devicetree node.

Example devicetree fragment:

&dac {
   #address-cells = <1>;
   #size-cells = <0>;
 
   channel@0 {
       reg = <0>;
       zephyr,resolution = <12>;
   };
 
   channel@1 {
       reg = <1>;
       zephyr,resolution = <12>;
       zephyr,buffered;
   };
};

Example usage:

static const struct dac_channel_cfg ch0_cfg_dt =
    DAC_CHANNEL_CFG_DT(DT_CHILD(DT_NODELABEL(dac), channel_0));
static const struct dac_channel_cfg ch1_cfg_dt =
    DAC_CHANNEL_CFG_DT(DT_CHILD(DT_NODELABEL(dac), channel_1));
 
// Initializes 'ch0_cfg_dt' to:
// {
//     .channel_id = 0,
//     .resolution = 12,
// }
// and 'ch1_cfg_dt' to:
// {
//     .channel_id = 1,
//     .resolution = 12,
//     .buffered = true,
// }

Parameters

node_id

Devicetree node identifier.

Returns

Static initializer for an dac_channel_cfg structure.

DAC_DT_SPEC_GET

#define DAC_DT_SPEC_GET

(

node_id

)

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_GET_BY_IDX(node_id, 0)

Equivalent to DAC_DT_SPEC_GET_BY_IDX(node_id, 0).

See also

DAC_DT_SPEC_GET_BY_IDX()

Parameters

node_id

Devicetree node identifier.

Returns

Static initializer for an dac_dt_spec structure.

DAC_DT_SPEC_GET_BY_IDX

#define DAC_DT_SPEC_GET_BY_IDX	(		node_id,
			idx )

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_STRUCT(DT_IO_CHANNELS_CTLR_BY_IDX(node_id, idx), \
                   COND_CODE_1(DT_PHA_HAS_CELL_AT_IDX(node_id, io_channels, idx, output), \
                               (DT_IO_CHANNELS_OUTPUT_BY_IDX(node_id, idx)), \
                               (0)))

Get DAC io-channel information from devicetree.

This returns a static initializer for an dac_dt_spec structure given a devicetree node and a channel index. The node must have the "io-channels" property defined.

Example devicetree fragment:

/ {
    zephyr,user {
        io-channels = <&dac0 1>, <&dac0 3>;
    };
};
 
&dac0 {
   #address-cells = <1>;
   #size-cells = <0>;
 
   channel@3 {
       reg = <3>;
 
       zephyr,resolution = <12>;
   };
};

Example usage:

static const struct dac_dt_spec dac_chan0 =
    DAC_DT_SPEC_GET_BY_IDX(DT_PATH(zephyr_user), 0);
static const struct dac_dt_spec dac_chan1 =
    DAC_DT_SPEC_GET_BY_IDX(DT_PATH(zephyr_user), 1);
 
// Initializes 'dac_chan0' to:
// {
//     .dev = DEVICE_DT_GET(DT_NODELABEL(dac0)),
//     .channel_id = 1,
// }
// and 'dac_chan1' to:
// {
//     .dev = DEVICE_DT_GET(DT_NODELABEL(dac0)),
//     .channel_id = 3,
//     .channel_cfg_dt_node_exists = true,
//     .channel_cfg = {
//         .channel_id = 3,
//         .resolution = 12
//     },
// }

See also

DAC_DT_SPEC_GET()

Parameters

node_id	Devicetree node identifier.
idx	Channel index.

Returns

Static initializer for an dac_dt_spec structure.

DAC_DT_SPEC_GET_BY_IDX_OR

#define DAC_DT_SPEC_GET_BY_IDX_OR	(		node_id,
			idx,
			default_value )

#include <zephyr/drivers/dac.h>

Value:

COND_CODE_1(DT_PROP_HAS_IDX(node_id, io_channels, idx), \
            (DAC_DT_SPEC_GET_BY_IDX(node_id, idx)), (default_value))

Like DAC_DT_SPEC_GET_BY_IDX(), with a fallback to a default value.

Parameters

node_id	Devicetree node identifier.
idx	Channel index.
default_value	Fallback value to expand to.

Returns

Static initializer for a struct dac_dt_spec for the property, or default_value if the node or property do not exist.

See also

DAC_DT_SPEC_INST_GET_BY_IDX_OR

DAC_DT_SPEC_GET_BY_NAME

#define DAC_DT_SPEC_GET_BY_NAME	(		node_id,
			name )

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_STRUCT(DT_IO_CHANNELS_CTLR_BY_NAME(node_id, name), \
                   DT_IO_CHANNELS_OUTPUT_BY_NAME(node_id, name))

Get DAC io-channel information from devicetree by name.

This returns a static initializer for an dac_dt_spec structure given a devicetree node and a channel name. The node must have the "io-channels" property defined.

Example devicetree fragment:

/ {
    zephyr,user {
        io-channels = <&dac0 1>, <&dac0 3>;
        io-channel-names = "A0", "A1";
    };
};
 
&dac0 {
   #address-cells = <1>;
   #size-cells = <0>;
 
   channel@3 {
       reg = <3>;
       zephyr,resolution = <12>;
   };
};

Example usage:

static const struct dac_dt_spec dac_chan0 =
    DAC_DT_SPEC_GET_BY_NAME(DT_PATH(zephyr_user), a0);
static const struct dac_dt_spec dac_chan1 =
    DAC_DT_SPEC_GET_BY_NAME(DT_PATH(zephyr_user), a1);
 
// Initializes 'dac_chan0' to:
// {
//     .dev = DEVICE_DT_GET(DT_NODELABEL(dac0)),
//     .channel_id = 1,
// }
// and 'dac_chan1' to:
// {
//     .dev = DEVICE_DT_GET(DT_NODELABEL(dac0)),
//     .channel_id = 3,
//     .channel_cfg_dt_node_exists = true,
//     .channel_cfg = {
//         .channel_id = 3,
//         .resolution = 12,
//     },
// }

Parameters

node_id	Devicetree node identifier.
name	Channel name.

Returns

Static initializer for an dac_dt_spec structure.

DAC_DT_SPEC_GET_BY_NAME_OR

#define DAC_DT_SPEC_GET_BY_NAME_OR	(		node_id,
			name,
			default_value )

#include <zephyr/drivers/dac.h>

Value:

COND_CODE_1(DT_PROP_HAS_NAME(node_id, io_channels, name), \
            (DAC_DT_SPEC_GET_BY_NAME(node_id, name)), (default_value))

Like DAC_DT_SPEC_GET_BY_NAME(), with a fallback to a default value.

Parameters

node_id	Devicetree node identifier.
name	Channel name.
default_value	Fallback value to expand to.

Returns

Static initializer for a struct dac_dt_spec for the property, or default_value if the node or property do not exist.

See also

DAC_DT_SPEC_INST_GET_BY_NAME_OR

DAC_DT_SPEC_GET_OR

#define DAC_DT_SPEC_GET_OR	(		node_id,
			default_value )

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_GET_BY_IDX_OR(node_id, 0, default_value)

Equivalent to DAC_DT_SPEC_GET_BY_IDX_OR(node_id, 0, default_value).

See also

DAC_DT_SPEC_GET_BY_IDX_OR()

Parameters

node_id	Devicetree node identifier.
default_value	Fallback value to expand to.

Returns

Static initializer for a struct dac_dt_spec for the property, or default_value if the node or property do not exist.

DAC_DT_SPEC_INST_GET

#define DAC_DT_SPEC_INST_GET

(

inst

)

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_GET(DT_DRV_INST(inst))

Equivalent to DAC_DT_SPEC_INST_GET_BY_IDX(inst, 0).

See also

DAC_DT_SPEC_GET()

Parameters

inst	DT_DRV_COMPAT instance number

Returns

Static initializer for an dac_dt_spec structure.

DAC_DT_SPEC_INST_GET_BY_IDX

#define DAC_DT_SPEC_INST_GET_BY_IDX	(		inst,
			idx )

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_GET_BY_IDX(DT_DRV_INST(inst), idx)

Get DAC io-channel information from a DT_DRV_COMPAT devicetree instance.

See also

DAC_DT_SPEC_GET_BY_IDX()

Parameters

inst	DT_DRV_COMPAT instance number
idx	Channel index.

Returns

Static initializer for an dac_dt_spec structure.

DAC_DT_SPEC_INST_GET_BY_IDX_OR

#define DAC_DT_SPEC_INST_GET_BY_IDX_OR	(		inst,
			idx,
			default_value )

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_GET_BY_IDX_OR(DT_DRV_INST(inst), idx, default_value)

Like DAC_DT_SPEC_INST_GET_BY_IDX(), with a fallback to a default value.

Parameters

inst	DT_DRV_COMPAT instance number
idx	Channel index.
default_value	Fallback value to expand to.

Returns

Static initializer for a struct dac_dt_spec for the property, or default_value if the node or property do not exist.

See also

DAC_DT_SPEC_GET_BY_IDX_OR

DAC_DT_SPEC_INST_GET_BY_NAME

#define DAC_DT_SPEC_INST_GET_BY_NAME	(		inst,
			name )

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_GET_BY_NAME(DT_DRV_INST(inst), name)

Get DAC io-channel information from a DT_DRV_COMPAT devicetree instance by name.

See also

DAC_DT_SPEC_GET_BY_NAME()

Parameters

inst	DT_DRV_COMPAT instance number
name	Channel name.

Returns

Static initializer for an dac_dt_spec structure.

DAC_DT_SPEC_INST_GET_BY_NAME_OR

#define DAC_DT_SPEC_INST_GET_BY_NAME_OR	(		inst,
			name,
			default_value )

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_GET_BY_NAME_OR(DT_DRV_INST(inst), name, default_value)

Like DAC_DT_SPEC_INST_GET_BY_NAME(), with a fallback to a default value.

Parameters

inst	DT_DRV_COMPAT instance number
name	Channel name.
default_value	Fallback value to expand to.

Returns

Static initializer for a struct dac_dt_spec for the property, or default_value if the node or property do not exist.

See also

DAC_DT_SPEC_GET_BY_NAME_OR

DAC_DT_SPEC_INST_GET_OR

#define DAC_DT_SPEC_INST_GET_OR	(		inst,
			default_value )

#include <zephyr/drivers/dac.h>

Value:

DAC_DT_SPEC_GET_OR(DT_DRV_INST(inst), default_value)

Equivalent to DAC_DT_SPEC_INST_GET_BY_IDX_OR(inst, 0, default).

See also

DAC_DT_SPEC_GET_OR()

Parameters

inst	DT_DRV_COMPAT instance number
default_value	Fallback value to expand to.

Returns

Static initializer for a struct dac_dt_spec for the property, or default_value if the node or property do not exist.

Typedef Documentation

dac_x_to_raw_fn

typedef int(* dac_x_to_raw_fn) (uint32_t ref_mv, uint8_t resolution, uint32_t *valp)

#include <zephyr/drivers/dac.h>

Conversion from specified input units to raw DAC units.

This function performs the necessary conversion to transform a physical voltage to a raw DAC value.

Parameters

ref_mv	the reference voltage used for the value, in millivolts.
resolution	the number of bits in the absolute value of the output.
valp	pointer to the physical voltage value on input, and the corresponding raw output value on successful conversion. If conversion fails the stored value is left unchanged.

Return values

0	on successful conversion

Function Documentation

dac_channel_setup()

int dac_channel_setup	(	const struct device *	dev,
		const struct dac_channel_cfg *	channel_cfg )

#include <zephyr/drivers/dac.h>

Configure a DAC channel.

It is required to call this function and configure each channel before it is selected for a write request.

Parameters

dev	Pointer to the device structure for the driver instance.
channel_cfg	Channel configuration.

Return values

0	On success.
-EINVAL	If a parameter with an invalid value has been provided.
-ENOTSUP	If the requested resolution is not supported.

dac_channel_setup_dt()

int dac_channel_setup_dt ( const struct dac_dt_spec * spec )

inlinestatic

#include <zephyr/drivers/dac.h>

Configure an DAC channel from a struct dac_dt_spec.

Parameters

spec	DAC specification from Devicetree.

Returns

A value from dac_channel_setup() or -ENOTSUP if information from Devicetree is not valid.

See also

dac_channel_setup()

dac_is_ready_dt()

bool dac_is_ready_dt ( const struct dac_dt_spec * spec )

inlinestatic

#include <zephyr/drivers/dac.h>

Validate that the DAC device is ready.

Parameters

spec	DAC specification from devicetree

Returns

true if the DAC device is ready for use and false otherwise.

dac_microvolts_to_raw()

int dac_microvolts_to_raw ( uint32_t ref_mv, uint8_t resolution, uint32_t * valp )

inlinestatic

#include <zephyr/drivers/dac.h>

Convert a raw DAC value to microvolts.

See also

dac_x_to_raw_fn

dac_microvolts_to_raw_dt()

int dac_microvolts_to_raw_dt ( const struct dac_dt_spec * spec, uint32_t * valp )

inlinestatic

#include <zephyr/drivers/dac.h>

Convert a microvolts value to raw DAC value using information stored in a struct dac_dt_spec.

Parameters

[in]	spec	DAC specification from Devicetree.
[in,out]	valp	Pointer to the raw measurement value on input, and the corresponding microvolt value on successful conversion. If conversion fails the stored value is left unchanged.

Returns

A value from dac_microvolts_to_raw() or -ENOTSUP if information from Devicetree is not valid.

See also

dac_microvolts_to_raw()

dac_millivolts_to_raw()

int dac_millivolts_to_raw ( uint32_t ref_mv, uint8_t resolution, uint32_t * valp )

inlinestatic

#include <zephyr/drivers/dac.h>

Convert a millivolts value to a raw DAC value.

See also

dac_x_to_raw_fn

dac_millivolts_to_raw_dt()

int dac_millivolts_to_raw_dt ( const struct dac_dt_spec * spec, uint32_t * valp )

inlinestatic

#include <zephyr/drivers/dac.h>

Convert a millivolts value to raw DAC using information stored in a struct dac_dt_spec.

Parameters

[in]	spec	DAC specification from Devicetree.
[in,out]	valp	Pointer to the raw measurement value on input, and the corresponding millivolt value on successful conversion. If conversion fails the stored value is left unchanged.

Returns

A value from dac_millivolts_to_raw() or -ENOTSUP if information from Devicetree is not valid.

See also

dac_millivolts_to_raw()

dac_write_value()

int dac_write_value	(	const struct device *	dev,
		uint8_t	channel,
		uint32_t	value )

#include <zephyr/drivers/dac.h>

Write a single value to a DAC channel.

Parameters

dev	Pointer to the device structure for the driver instance.
channel	Number of the channel to be used.
value	Data to be written to DAC output registers.

Return values

0	On success.
-EINVAL	If a parameter with an invalid value has been provided.

dac_write_value_dt()

int dac_write_value_dt ( const struct dac_dt_spec * spec, uint32_t value )

inlinestatic

#include <zephyr/drivers/dac.h>

Write a single value to a DAC channel from a struct dac_dt_spec.

Parameters

spec	DAC specification from Devicetree.
value	Data to be written to DAC output registers.

Returns

A value from dac_write_value() or -ENOTSUP if information from Devicetree is not valid.

See also

dac_write_value()

dac_x_to_raw_dt_chan()

int dac_x_to_raw_dt_chan ( dac_x_to_raw_fn conv_func, const struct dac_dt_spec * spec, uint32_t * valp )

inlinestatic

#include <zephyr/drivers/dac.h>

Convert a raw DAC value to an arbitrary output unit.

Parameters

[in]	conv_func	Function that converts to the final output unit.
[in]	spec	DAC specification from Devicetree.
[in,out]	valp	pointer to the physical voltage value on input, and the corresponding raw output value on successful conversion. If conversion fails the stored value is left unchanged.

Returns

A value from dac_x_to_raw_dt_chan or -ENOTSUP if information from Devicetree is not valid.

See also

dac_x_to_raw_fn