DAC Module¶

The buffered digital to analog converter (DAC) API provides a set of functions for programming the digital circuits of the DAC. Functions are provided to set the reference voltage, the synchronization mode, the internal 12-bit DAC value, and set the state of the DAC output.

group dac_api

Defines

DAC_REG_BYTE_MASK (0xFFU)¶: Register Byte Mask.

DAC_LOCK_KEY (0xA000U)¶: DAC Lock Key.

DAC_LOCK_CONTROL (0x1U)¶: Lock the control register.

DAC_LOCK_SHADOW (0x2U)¶: Lock the shadow value register.

DAC_LOCK_OUTPUT (0x4U)¶: Lock the output enable register.

Enums

enum DAC_ReferenceVoltage¶

Values that can be passed to DAC_setReferenceVoltage() as the source parameter.

Values:

enumerator DAC_REF_VDAC = 0¶: VDAC reference voltage.

enumerator DAC_REF_ADC_VREFHI = 1¶: ADC VREFHI reference voltage.

enum DAC_LoadMode¶

Values that can be passed to DAC_setLoadMode() as the mode parameter.

Values:

enumerator DAC_LOAD_SYSCLK = 0¶: Load on next SYSCLK.

enumerator DAC_LOAD_PWMSYNC = 4¶: Load on next PWMSYNC specified by SYNCSEL.

Functions

uint16_t DAC_getRevision(uint32_t base)¶

Get the DAC Revision value

This function gets the DAC revision value.

Parameters

base: is the DAC module base address

Return: Returns the DAC revision value.

void DAC_setReferenceVoltage(uint32_t base, DAC_ReferenceVoltage source)¶

Sets the DAC Reference Voltage

This function sets the DAC reference voltage.

Parameters

base: is the DAC module base address
source: is the selected reference voltage

The source parameter can have one of two values:

DAC_REF_VDAC - The VDAC reference voltage
DAC_REF_ADC_VREFHI - The ADC VREFHI reference voltage

Return: None.

void DAC_setLoadMode(uint32_t base, DAC_LoadMode mode)¶

Sets the DAC Load Mode

This function sets the DAC load mode.

Parameters

base: is the DAC module base address
mode: is the selected load mode

The mode parameter can have one of two values:

DAC_LOAD_SYSCLK - Load on next SYSCLK
DAC_LOAD_PWMSYNC - Load on next PWMSYNC specified by SYNCSEL

Return: None.

void DAC_setPWMSyncSignal(uint32_t base, uint16_t signal)¶

Sets the DAC PWMSYNC Signal

This function sets the DAC PWMSYNC signal.

Parameters

base: is the DAC module base address
signal: is the selected PWM signal

The signal parameter must be set to a number that represents the PWM signal that will be set. For instance, passing 2 into signal will select PWM sync signal 2.

Return: None.

uint16_t DAC_getActiveValue(uint32_t base)¶

Get the DAC Active Output Value

This function gets the DAC active output value.

Parameters

base: is the DAC module base address

Return: Returns the DAC active output value.

void DAC_setShadowValue(uint32_t base, uint16_t value)¶

Set the DAC Shadow Output Value

This function sets the DAC shadow output value.

Parameters

base: is the DAC module base address
value: is the 12-bit code to be loaded into the active value register

Return: None.

uint16_t DAC_getShadowValue(uint32_t base)¶

Get the DAC Shadow Output Value

This function gets the DAC shadow output value.

Parameters

base: is the DAC module base address

Return: Returns the DAC shadow output value.

void DAC_enableOutput(uint32_t base)¶

Enable the DAC Output

This function enables the DAC output.

Parameters

base: is the DAC module base address

Note: A delay is required after enabling the DAC. Further details regarding the exact delay time length can be found in the device datasheet.
Return: None.

void DAC_disableOutput(uint32_t base)¶

Disable the DAC Output

This function disables the DAC output.

Parameters

base: is the DAC module base address

Return: None.

void DAC_setOffsetTrim(uint32_t base, int16_t offset)¶

Set DAC Offset Trim

This function sets the DAC offset trim. The

offset value should be a signed number in the range of -128 to 127.

Parameters

base: is the DAC module base address
offset: is the specified value for the offset trim

Note: The offset should not be modified unless specifically indicated by TI Errata or other documentation. Modifying the offset value could cause this module to operate outside of the datasheet specifications.
Return: None.

int16_t DAC_getOffsetTrim(uint32_t base)¶

Get DAC Offset Trim

This function gets the DAC offset trim value.

Parameters

base: is the DAC module base address

Return: None.

void DAC_lockRegister(uint32_t base, uint16_t reg)¶

Lock write-access to DAC Register

This function locks the write-access to the specified DAC register. Only a system reset can unlock the register once locked.

Parameters

base: is the DAC module base address
reg: is the selected DAC registers

The reg parameter can be an ORed combination of any of the following values:

DAC_LOCK_CONTROL - Lock the DAC control register
DAC_LOCK_SHADOW - Lock the DAC shadow value register
DAC_LOCK_OUTPUT - Lock the DAC output enable/disable register

Return: None.

bool DAC_isRegisterLocked(uint32_t base, uint16_t reg)¶

Check if DAC Register is locked

This function checks if write-access has been locked on the specified DAC register.

Parameters

base: is the DAC module base address
reg: is the selected DAC register locks to check

The reg parameter can be an ORed combination of any of the following values:

DAC_LOCK_CONTROL - Lock the DAC control register
DAC_LOCK_SHADOW - Lock the DAC shadow value register
DAC_LOCK_OUTPUT - Lock the DAC output enable/disable register

Return: Returns true if any of the registers specified are locked, and false if all specified registers aren’t locked.

void DAC_tuneOffsetTrim(uint32_t base, float32_t referenceVoltage)¶

Tune DAC Offset Trim

This function adjusts/tunes the DAC offset trim. The

referenceVoltage value should be a floating point number in the range specified in the device data manual.

Parameters

base: is the DAC module base address
referenceVoltage: is the reference voltage the DAC module is operating at.

Note: Use this function to adjust the DAC offset trim if operating at a reference voltage other than 2.5v. Since this function modifies the DAC offset trim register, it should only be called once after Device_cal. If it is called multiple times after Device_cal, the offset value scaled would be the wrong value.
Return: None.

The code for this module is contained in driverlib/dac.c, with driverlib/dac.h containing the API declarations for use by applications.