VDAC - Voltage DAC#

Digital to Analog Voltage Converter (VDAC) Peripheral API.

This module contains functions to control the VDAC peripheral of Silicon Labs' 32-bit MCUs and SoCs. VDAC converts digital values to analog signals at up to 500 ksps with 12-bit accuracy. VDAC is designed for low energy consumption, but can also provide very good performance.

The following steps are necessary for basic operation:

Clock enable:

CMU_ClockEnable(cmuClock_VDAC0, true);

Initialize the VDAC with default settings and modify selected fields:

VDAC_Init_TypeDef vdacInit          = VDAC_INIT_DEFAULT;
VDAC_InitChannel_TypeDef vdacChInit = VDAC_INITCHANNEL_DEFAULT;

// Set prescaler to get 1 MHz VDAC clock frequency.
vdacInit.prescaler = VDAC_PrescaleCalc(1000000, true, 0); // function call for series 0/1
VDAC_Init(VDAC0, &vdacInit);

vdacChInit.enable = true;
VDAC_InitChannel(VDAC0, &vdacChInit, 0);

Perform a conversion:

VDAC_ChannelOutputSet(VDAC0, 0, 250);

Note

The output stage of a VDAC channel consists of an on-chip operational amplifier (OPAMP) in the OPAMP module. This OPAMP is highly configurable; and to exploit the VDAC functionality fully, configure the OPAMP using the OPAMP API. Using the OPAMP API also loads OPAMP calibration values. The default (reset) settings of OPAMP is sufficient for many applications.

Modules#

VDAC_Init_TypeDef

VDAC_InitChannel_TypeDef

Enumerations#

enum

VDAC_Refresh_TypeDef {

vdacRefresh2 = _VDAC_CFG_REFRESHPERIOD_CYCLES2

vdacRefresh4 = _VDAC_CFG_REFRESHPERIOD_CYCLES4

vdacRefresh8 = _VDAC_CFG_REFRESHPERIOD_CYCLES8

vdacRefresh16 = _VDAC_CFG_REFRESHPERIOD_CYCLES16

vdacRefresh32 = _VDAC_CFG_REFRESHPERIOD_CYCLES32

vdacRefresh64 = _VDAC_CFG_REFRESHPERIOD_CYCLES64

vdacRefresh128 = _VDAC_CFG_REFRESHPERIOD_CYCLES128

vdacRefresh256 = _VDAC_CFG_REFRESHPERIOD_CYCLES256

}

Channel refresh period.

enum

VDAC_TimerOverflow_TypeDef {

vdacCycles2 = _VDAC_CFG_TIMEROVRFLOWPERIOD_CYCLES2

vdacCycles4 = _VDAC_CFG_TIMEROVRFLOWPERIOD_CYCLES4

vdacCycles8 = _VDAC_CFG_TIMEROVRFLOWPERIOD_CYCLES8

vdacCycles16 = _VDAC_CFG_TIMEROVRFLOWPERIOD_CYCLES16

vdacCycles32 = _VDAC_CFG_TIMEROVRFLOWPERIOD_CYCLES32

vdacCycles64 = _VDAC_CFG_TIMEROVRFLOWPERIOD_CYCLES64

}

Timer overflow period.

enum

VDAC_Ref_TypeDef {

vdacRef1V25 = _VDAC_CFG_REFRSEL_V125

vdacRef2V5 = _VDAC_CFG_REFRSEL_V25

vdacRefAvdd = _VDAC_CFG_REFRSEL_VDD

vdacRefExtPin = _VDAC_CFG_REFRSEL_EXT

}

Reference voltage for VDAC.

enum

VDAC_RefreshSource_TypeDef {

vdacRefreshSrcNone = _VDAC_CH0CFG_REFRESHSOURCE_NONE

vdacRefreshSrcRefreshTimer = _VDAC_CH0CFG_REFRESHSOURCE_REFRESHTIMER

vdacRefreshSrcSyncPrs = _VDAC_CH0CFG_REFRESHSOURCE_SYNCPRS

vdacRefreshSrcAsyncPrs = _VDAC_CH0CFG_REFRESHSOURCE_ASYNCPRS

}

Refresh source for VDAC.

enum

VDAC_TrigMode_TypeDef {

vdacTrigModeNone = _VDAC_CH0CFG_TRIGMODE_NONE

vdacTrigModeSw = _VDAC_CH0CFG_TRIGMODE_SW

vdacTrigModeSyncPrs = _VDAC_CH0CFG_TRIGMODE_SYNCPRS

vdacTrigModeInternalTimer = _VDAC_CH0CFG_TRIGMODE_INTERNALTIMER

vdacTrigModeAsyncPrs = _VDAC_CH0CFG_TRIGMODE_ASYNCPRS

}

Channel conversion trigger mode.

enum

VDAC_PowerMode_TypeDef {

vdacPowerModeHighPower = _VDAC_CH0CFG_POWERMODE_HIGHPOWER

vdacPowerModeLowPower = _VDAC_CH0CFG_POWERMODE_LOWPOWER

}

Channel power mode.

enum

VDAC_ChPortSel_t {

vdacChPortNone = _VDAC_OUTCTRL_ABUSPORTSELCH0_NONE

vdacChPortA = _VDAC_OUTCTRL_ABUSPORTSELCH0_PORTA

vdacChPortB = _VDAC_OUTCTRL_ABUSPORTSELCH0_PORTB

vdacChPortC = _VDAC_OUTCTRL_ABUSPORTSELCH0_PORTC

vdacChPortD = _VDAC_OUTCTRL_ABUSPORTSELCH0_PORTD

}

VDAC channel Abus port selection.

Functions#

void

VDAC_ChannelOutputSet(VDAC_TypeDef *vdac, unsigned int channel, uint32_t value)

Set the output signal of a VDAC channel to a given value.

void

VDAC_Enable(VDAC_TypeDef *vdac, unsigned int ch, bool enable)

Enable/disable the VDAC channel.

void

VDAC_Init(VDAC_TypeDef *vdac, const VDAC_Init_TypeDef *init)

Initialize VDAC.

void

VDAC_InitChannel(VDAC_TypeDef *vdac, const VDAC_InitChannel_TypeDef *init, unsigned int ch)

Initialize a VDAC channel.

void

VDAC_SineModeStart(VDAC_TypeDef *vdac, bool start)

Start/stop Sinemode.

void

VDAC_Channel0OutputSet(VDAC_TypeDef *vdac, uint32_t value)

Set the output signal of VDAC channel 0 to a given value.

void

VDAC_Channel1OutputSet(VDAC_TypeDef *vdac, uint32_t value)

Set the output signal of VDAC channel 1 to a given value.

void

VDAC_IntClear(VDAC_TypeDef *vdac, uint32_t flags)

Clear one or more pending VDAC interrupts.

void

VDAC_IntDisable(VDAC_TypeDef *vdac, uint32_t flags)

Disable one or more VDAC interrupts.

void

VDAC_IntEnable(VDAC_TypeDef *vdac, uint32_t flags)

Enable one or more VDAC interrupts.

uint32_t

VDAC_IntGet(VDAC_TypeDef *vdac)

Get pending VDAC interrupt flags.

uint32_t

VDAC_IntGetEnabled(VDAC_TypeDef *vdac)

Get enabled and pending VDAC interrupt flags.

void

VDAC_IntSet(VDAC_TypeDef *vdac, uint32_t flags)

Set one or more pending VDAC interrupts from SW.

uint32_t

VDAC_GetStatus(VDAC_TypeDef *vdac)

Get the VDAC Status register.

uint32_t

VDAC_PrescaleCalc(VDAC_TypeDef *vdac, uint32_t vdacFreq)

Calculate the prescaler value used to determine VDAC clock.

void

VDAC_Reset(VDAC_TypeDef *vdac)

Reset VDAC to same state that it was in after a hardwares reset.

Macros#

#define

VDAC_INIT_DEFAULT undefined

Default configuration for VDAC initialization structure.

#define

VDAC_INIT_SINE_GENERATION_MODE undefined

Sine mode configuration for VDAC initialization structure.

#define

VDAC_INITCHANNEL_DEFAULT undefined

Default configuration for VDAC channel initialization structure.

Enumeration Documentation#

VDAC_Refresh_TypeDef#

VDAC_Refresh_TypeDef

Channel refresh period.

Enumerator
vdacRefresh2	Refresh every 2 clock cycles.
vdacRefresh4	Refresh every 4 clock cycles.
vdacRefresh8	Refresh every 8 clock cycles.
vdacRefresh16	Refresh every 16 clock cycles.
vdacRefresh32	Refresh every 32 clock cycles.
vdacRefresh64	Refresh every 64 clock cycles.
vdacRefresh128	Refresh every 128 clock cycles.
vdacRefresh256	Refresh every 256 clock cycles.

Definition at line 242 of file platform/emlib/inc/em_vdac.h

VDAC_TimerOverflow_TypeDef#

VDAC_TimerOverflow_TypeDef

Timer overflow period.

Enumerator
vdacCycles2	Overflows every 2 clock cycles.
vdacCycles4	Overflows every 4 clock cycles.
vdacCycles8	Overflows every 8 clock cycles.
vdacCycles16	Overflows every 16 clock cycles.
vdacCycles32	Overflows every 32 clock cycles.
vdacCycles64	Overflows every 64 clock cycles.

Definition at line 254 of file platform/emlib/inc/em_vdac.h

VDAC_Ref_TypeDef#

VDAC_Ref_TypeDef

Reference voltage for VDAC.

Enumerator
vdacRef1V25	Internal 1.25 V band gap reference.
vdacRef2V5	Internal 2.5 V band gap reference.
vdacRefAvdd	AVDD reference.
vdacRefExtPin	External pin reference.

Definition at line 264 of file platform/emlib/inc/em_vdac.h

VDAC_RefreshSource_TypeDef#

VDAC_RefreshSource_TypeDef

Refresh source for VDAC.

Enumerator
vdacRefreshSrcNone	No refresh source.
vdacRefreshSrcRefreshTimer	Refresh triggered by refresh timer overflow.
vdacRefreshSrcSyncPrs	Refresh triggered by sync PRS.
vdacRefreshSrcAsyncPrs	Refresh triggered by async PRS.

Definition at line 272 of file platform/emlib/inc/em_vdac.h

VDAC_TrigMode_TypeDef#

VDAC_TrigMode_TypeDef

Channel conversion trigger mode.

Enumerator
vdacTrigModeNone	No conversion trigger source selected.
vdacTrigModeSw	Channel is triggered by CHnDATA or COMBDATA write.
vdacTrigModeSyncPrs	Channel is triggered by Sync PRS input.
vdacTrigModeInternalTimer	Channel is triggered by Internal Timer.
vdacTrigModeAsyncPrs	Channel is triggered by Async PRS input.

Definition at line 280 of file platform/emlib/inc/em_vdac.h

VDAC_PowerMode_TypeDef#

VDAC_PowerMode_TypeDef

Channel power mode.

Enumerator
vdacPowerModeHighPower	High power buffer mode.
vdacPowerModeLowPower	Low power buffer mode.

Definition at line 292 of file platform/emlib/inc/em_vdac.h

VDAC_ChPortSel_t#

VDAC_ChPortSel_t

VDAC channel Abus port selection.

Enumerator
vdacChPortNone	No GPIO selected.
vdacChPortA	Port A selected.
vdacChPortB	Port B selected.
vdacChPortC	Port C selected.
vdacChPortD	Port D selected.

Definition at line 298 of file platform/emlib/inc/em_vdac.h

Function Documentation#

VDAC_ChannelOutputSet#

void VDAC_ChannelOutputSet (VDAC_TypeDef *vdac, unsigned int channel, uint32_t value)

Set the output signal of a VDAC channel to a given value.

Parameters

[in]	vdac	A pointer to the VDAC peripheral register block.
[in]	channel	A channel number to set the output of.
[in]	value	A value to write to the channel output register CHnDATA.

This function sets the output signal of a VDAC channel by writing value to the corresponding CHnDATA register.

Definition at line 426 of file platform/emlib/src/em_vdac.c

VDAC_Enable#

void VDAC_Enable (VDAC_TypeDef *vdac, unsigned int ch, bool enable)

Enable/disable the VDAC channel.

Parameters

[in]	vdac	A pointer to the VDAC peripheral register block.
[in]	ch	A channel to enable/disable.
[in]	enable	True to enable VDAC channel, false to disable.

Definition at line 114 of file platform/emlib/src/em_vdac.c

VDAC_Init#

void VDAC_Init (VDAC_TypeDef *vdac, const VDAC_Init_TypeDef *init)

Initialize VDAC.

Parameters

[in]	vdac	A pointer to the VDAC peripheral register block.
[in]	init	A pointer to the VDAC initialization structure.

Initializes the common parts for both channels. This function will also load calibration values from the Device Information (DI) page into the VDAC calibration register. To complete a VDAC setup, channel control configuration must also be done. See VDAC_InitChannel().

Note

This function will disable both channels prior to configuration.

Definition at line 182 of file platform/emlib/src/em_vdac.c

VDAC_InitChannel#

void VDAC_InitChannel (VDAC_TypeDef *vdac, const VDAC_InitChannel_TypeDef *init, unsigned int ch)

Initialize a VDAC channel.

Parameters

[in]	vdac	A pointer to the VDAC peripheral register block.
[in]	init	A pointer to the VDAC channel initialization structure.
[in]	ch	A channel number to initialize.

Definition at line 315 of file platform/emlib/src/em_vdac.c

VDAC_SineModeStart#

void VDAC_SineModeStart (VDAC_TypeDef *vdac, bool start)

Start/stop Sinemode.

Parameters

[in]	vdac	Pointer to VDAC peripheral register block.
[in]	start	True to start the Sine mode, false to stop it.

This function sends the sine mode start/stop signal to the DAC.

Definition at line 539 of file platform/emlib/inc/em_vdac.h

VDAC_Channel0OutputSet#

void VDAC_Channel0OutputSet (VDAC_TypeDef *vdac, uint32_t value)

Set the output signal of VDAC channel 0 to a given value.

Parameters

[in]	vdac	Pointer to VDAC peripheral register block.
[in]	value	Value to write to channel 0 output register CH0DATA.

This function sets the output signal of VDAC channel 0 by writing value to the CH0DATA register.

Definition at line 572 of file platform/emlib/inc/em_vdac.h

VDAC_Channel1OutputSet#

void VDAC_Channel1OutputSet (VDAC_TypeDef *vdac, uint32_t value)

Set the output signal of VDAC channel 1 to a given value.

Parameters

[in]	vdac	Pointer to VDAC peripheral register block.
[in]	value	Value to write to channel 1 output register CH1DATA.

This function sets the output signal of VDAC channel 1 by writing value to the CH1DATA register.

Definition at line 598 of file platform/emlib/inc/em_vdac.h

VDAC_IntClear#

void VDAC_IntClear (VDAC_TypeDef *vdac, uint32_t flags)

Clear one or more pending VDAC interrupts.

Parameters

[in]	vdac	Pointer to VDAC peripheral register block.
[in]	flags	Pending VDAC interrupt source to clear. Use a bitwise logic OR combination of valid interrupt flags for the VDAC module (VDAC_IF_nnn).

Definition at line 621 of file platform/emlib/inc/em_vdac.h

VDAC_IntDisable#

void VDAC_IntDisable (VDAC_TypeDef *vdac, uint32_t flags)

Disable one or more VDAC interrupts.

Parameters

[in]	vdac	Pointer to VDAC peripheral register block.
[in]	flags	VDAC interrupt sources to disable. Use a bitwise logic OR combination of valid interrupt flags for the VDAC module (VDAC_IF_nnn).

Definition at line 641 of file platform/emlib/inc/em_vdac.h

VDAC_IntEnable#

void VDAC_IntEnable (VDAC_TypeDef *vdac, uint32_t flags)

Enable one or more VDAC interrupts.

Parameters

[in]	vdac	Pointer to VDAC peripheral register block.
[in]	flags	VDAC interrupt sources to enable. Use a bitwise logic OR combination of valid interrupt flags for the VDAC module (VDAC_IF_nnn).

Note

Depending on the use, a pending interrupt may already be set prior to enabling the interrupt. To ignore a pending interrupt, consider using VDAC_IntClear() prior to enabling the interrupt.

Definition at line 666 of file platform/emlib/inc/em_vdac.h

VDAC_IntGet#

uint32_t VDAC_IntGet (VDAC_TypeDef *vdac)

Get pending VDAC interrupt flags.

Parameters

[in]

vdac

Pointer to VDAC peripheral register block.

Note

The event bits are not cleared by the use of this function.

Returns

VDAC interrupt sources pending. Use a bitwise logic OR combination of valid interrupt flags for the VDAC module (VDAC_IF_nnn).

Definition at line 689 of file platform/emlib/inc/em_vdac.h

VDAC_IntGetEnabled#

uint32_t VDAC_IntGetEnabled (VDAC_TypeDef *vdac)

Get enabled and pending VDAC interrupt flags.

Parameters

[in]

vdac

Pointer to VDAC peripheral register block.

Useful for handling more interrupt sources in the same interrupt handler.

Note

Interrupt flags are not cleared by the use of this function.

Returns

Pending and enabled VDAC interrupt sources. The return value is the bitwise AND combination of
- the OR combination of enabled interrupt sources in VDACx_IEN_nnn register (VDACx_IEN_nnn) and
- the OR combination of valid interrupt flags of the VDAC module (VDACx_IF_nnn).

Definition at line 713 of file platform/emlib/inc/em_vdac.h

VDAC_IntSet#

void VDAC_IntSet (VDAC_TypeDef *vdac, uint32_t flags)

Set one or more pending VDAC interrupts from SW.

Parameters

[in]	vdac	Pointer to VDAC peripheral register block.
[in]	flags	VDAC interrupt sources to set to pending. Use a bitwise logic OR combination of valid interrupt flags for the VDAC module (VDAC_IF_nnn).

Definition at line 732 of file platform/emlib/inc/em_vdac.h

VDAC_GetStatus#

uint32_t VDAC_GetStatus (VDAC_TypeDef *vdac)

Get the VDAC Status register.

Parameters

[in]

vdac

Pointer to VDAC peripheral register block.

Returns

Current STATUS register value.

Definition at line 752 of file platform/emlib/inc/em_vdac.h

VDAC_PrescaleCalc#

uint32_t VDAC_PrescaleCalc (VDAC_TypeDef *vdac, uint32_t vdacFreq)

Calculate the prescaler value used to determine VDAC clock.

Parameters

[in]	vdac	Pointer to VDAC peripheral register block.
[in]	vdacFreq	VDAC frequency target. The frequency will automatically be adjusted to be below maximum allowed VDAC clock.

The VDAC clock is given by the input clock divided by the prescaler+1.

VDAC_CLK = IN_CLK / (prescale + 1)

The maximum VDAC clock is 1 MHz.

Note

If the requested VDAC frequency is low and the maximum prescaler value can't adjust the actual VDAC frequency lower than requested, the maximum prescaler value is returned resulting in a higher VDAC frequency than requested.

Returns

A prescaler value to use for VDAC to achieve a clock value less than or equal to vdacFreq.

Definition at line 539 of file platform/emlib/src/em_vdac.c

VDAC_Reset#

void VDAC_Reset (VDAC_TypeDef *vdac)

Reset VDAC to same state that it was in after a hardwares reset.

Parameters

[in]

vdac

A pointer to the VDAC peripheral register block.

Definition at line 587 of file platform/emlib/src/em_vdac.c

Macro Definition Documentation#

VDAC_INIT_DEFAULT#

#define VDAC_INIT_DEFAULT

Value:

{ \

_VDAC_CFG_WARMUPTIME_DEFAULT, /* Number of prescaled DAC_CLK for Vdac to warmup. */ \

false, /* Continue while debugging. */ \

true, /* On demand clock. */ \

false, /* DMA wake up. */ \

false, /* Bias keep warm. */ \

vdacRefresh8, /* Refresh every 8th cycle. */ \

vdacCycles2, /* Internal overflow every 8th cycle. */ \

0, /* No prescaling. */ \

vdacRef1V25, /* 1.25 V internal low noise reference. */ \

false, /* Do not reset prescaler on CH 0 start. */ \

false, /* Sine wave is stopped at the sample its currently outputting. */ \

false, /* Disable sine mode. */ \

false, /* Differential mode. */ \

}

Default configuration for VDAC initialization structure.

Definition at line 388 of file platform/emlib/inc/em_vdac.h

VDAC_INIT_SINE_GENERATION_MODE#

#define VDAC_INIT_SINE_GENERATION_MODE

Value:

{ \

_VDAC_CFG_WARMUPTIME_DEFAULT, /* Number of prescaled DAC_CLK for Vdac to warmup. */ \

false, /* Continue while debugging. */ \

true, /* On demand clock. */ \

false, /* DMA wake up. */ \

false, /* Bias keep warm. */ \

vdacRefresh8, /* Refresh every 8th cycle. */ \

vdacCycles2, /* Internal overflow every 8th cycle. */ \

0, /* No prescaling. */ \

vdacRef1V25, /* 1.25 V internal low noise reference. */ \

false, /* Do not reset prescaler on CH 0 start. */ \

false, /* Sine wave is stopped at the sample its currently outputting. */ \

true, /* Enable sine mode. */ \

false, /* Differential mode. */ \

}

Sine mode configuration for VDAC initialization structure.

Definition at line 428 of file platform/emlib/inc/em_vdac.h

VDAC_INITCHANNEL_DEFAULT#

#define VDAC_INITCHANNEL_DEFAULT

Value:

{ \

false, /* Leave channel disabled when initialization is done. */ \

false, /* Turn off between sample off conversions.*/ \

true, /* Enable High cap mode. */ \

0, /* FIFO data low watermark at 0. */ \

vdacRefreshSrcNone, /* Channel refresh source. */ \

vdacTrigModeSw, /* Conversion trigged by CH0DATA or COMBDATA write. */ \

vdacPowerModeHighPower, /* High power mode enabled. */ \

false, /* Continuous conversion mode. */ \

0, /* ABUS pin selected. */ \

vdacChPortNone, /* No Analog bus port selected. */ \

false, /* Output not shorted */ \

false, /* Alternative output disabled. */ \

true, /* Main output enabled. */ \

0, /* Hold out time. Previously called settle time */ \

}

Default configuration for VDAC channel initialization structure.

Definition at line 493 of file platform/emlib/inc/em_vdac.h