VDAC - Voltage DAC

Description

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.

Data Structures

struct  VDAC_Init_TypeDef
 VDAC initialization structure, common for both channels.
 
struct  VDAC_InitChannel_TypeDef
 VDAC channel initialization structure.
 

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_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_PrescaleCalc (uint32_t vdacFreq, bool syncMode, uint32_t hfperFreq)
 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
 Default configuration for VDAC initialization structure.
 
#define VDAC_INITCHANNEL_DEFAULT
 Default configuration for VDAC channel initialization structure.
 

Enumerations

enum  VDAC_Refresh_TypeDef {
  vdacRefresh8 = _VDAC_CTRL_REFRESHPERIOD_8CYCLES,
  vdacRefresh16 = _VDAC_CTRL_REFRESHPERIOD_16CYCLES,
  vdacRefresh32 = _VDAC_CTRL_REFRESHPERIOD_32CYCLES,
  vdacRefresh64 = _VDAC_CTRL_REFRESHPERIOD_64CYCLES
}
 Channel refresh period.
 
enum  VDAC_Ref_TypeDef {
  vdacRef1V25Ln = _VDAC_CTRL_REFSEL_1V25LN,
  vdacRef2V5Ln = _VDAC_CTRL_REFSEL_2V5LN,
  vdacRef1V25 = _VDAC_CTRL_REFSEL_1V25,
  vdacRef2V5 = _VDAC_CTRL_REFSEL_2V5,
  vdacRefAvdd = _VDAC_CTRL_REFSEL_VDD,
  vdacRefExtPin = _VDAC_CTRL_REFSEL_EXT
}
 Reference voltage for VDAC.
 
enum  VDAC_PrsSel_TypeDef {
  vdacPrsSelCh0 = _VDAC_CH0CTRL_PRSSEL_PRSCH0,
  vdacPrsSelCh1 = _VDAC_CH0CTRL_PRSSEL_PRSCH1,
  vdacPrsSelCh2 = _VDAC_CH0CTRL_PRSSEL_PRSCH2,
  vdacPrsSelCh3 = _VDAC_CH0CTRL_PRSSEL_PRSCH3,
  vdacPrsSelCh4 = _VDAC_CH0CTRL_PRSSEL_PRSCH4,
  vdacPrsSelCh5 = _VDAC_CH0CTRL_PRSSEL_PRSCH5,
  vdacPrsSelCh6 = _VDAC_CH0CTRL_PRSSEL_PRSCH6,
  vdacPrsSelCh7 = _VDAC_CH0CTRL_PRSSEL_PRSCH7,
  vdacPrsSelCh8 = _VDAC_CH0CTRL_PRSSEL_PRSCH8,
  vdacPrsSelCh9 = _VDAC_CH0CTRL_PRSSEL_PRSCH9,
  vdacPrsSelCh10 = _VDAC_CH0CTRL_PRSSEL_PRSCH10,
  vdacPrsSelCh11 = _VDAC_CH0CTRL_PRSSEL_PRSCH11
}
 Peripheral Reflex System signal used to trigger VDAC channel conversion.
 
enum  VDAC_TrigMode_TypeDef {
  vdacTrigModeSw = _VDAC_CH0CTRL_TRIGMODE_SW,
  vdacTrigModePrs = _VDAC_CH0CTRL_TRIGMODE_PRS,
  vdacTrigModeRefresh = _VDAC_CH0CTRL_TRIGMODE_REFRESH,
  vdacTrigModeSwPrs = _VDAC_CH0CTRL_TRIGMODE_SWPRS,
  vdacTrigModeSwRefresh = _VDAC_CH0CTRL_TRIGMODE_SWREFRESH,
  vdacTrigModeLesense = _VDAC_CH0CTRL_TRIGMODE_LESENSE
}
 Channel conversion trigger mode.
 

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.

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

Parameters
[in]vdacA pointer to the VDAC peripheral register block.
[in]channelA channel number to set the output of.
[in]valueA value to write to the channel output register CHnDATA.

◆ VDAC_Enable()

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

Enable/disable the VDAC channel.

Parameters
[in]vdacA pointer to the VDAC peripheral register block.
[in]chA channel to enable/disable.
[in]enableTrue to enable VDAC channel, false to disable.

◆ VDAC_Init()

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

Initialize VDAC.

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.
Parameters
[in]vdacA pointer to the VDAC peripheral register block.
[in]initA pointer to the VDAC initialization structure.

◆ VDAC_InitChannel()

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

Initialize a VDAC channel.

Parameters
[in]vdacA pointer to the VDAC peripheral register block.
[in]initA pointer to the VDAC channel initialization structure.
[in]chA channel number to initialize.

◆ VDAC_Channel0OutputSet()

void VDAC_Channel0OutputSet ( VDAC_TypeDef *  vdac,
uint32_t  value 
)
inline

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

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

Parameters
[in]vdacPointer to VDAC peripheral register block.
[in]valueValue to write to channel 0 output register CH0DATA.

◆ VDAC_Channel1OutputSet()

void VDAC_Channel1OutputSet ( VDAC_TypeDef *  vdac,
uint32_t  value 
)
inline

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

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

Parameters
[in]vdacPointer to VDAC peripheral register block.
[in]valueValue to write to channel 1 output register CH1DATA.

◆ VDAC_IntClear()

void VDAC_IntClear ( VDAC_TypeDef *  vdac,
uint32_t  flags 
)
inline

Clear one or more pending VDAC interrupts.

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

◆ VDAC_IntDisable()

void VDAC_IntDisable ( VDAC_TypeDef *  vdac,
uint32_t  flags 
)
inline

Disable one or more VDAC interrupts.

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

◆ VDAC_IntEnable()

void VDAC_IntEnable ( VDAC_TypeDef *  vdac,
uint32_t  flags 
)
inline

Enable one or more VDAC interrupts.

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

◆ VDAC_IntGet()

uint32_t VDAC_IntGet ( VDAC_TypeDef *  vdac)
inline

Get pending VDAC interrupt flags.

Note
The event bits are not cleared by the use of this function.
Parameters
[in]vdacPointer to VDAC peripheral register block.
Returns
VDAC interrupt sources pending. Use a bitwise logic OR combination of valid interrupt flags for the VDAC module (VDAC_IF_nnn).

◆ VDAC_IntGetEnabled()

uint32_t VDAC_IntGetEnabled ( VDAC_TypeDef *  vdac)
inline

Get enabled and pending VDAC interrupt flags.

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

Parameters
[in]vdacPointer to VDAC peripheral register block.
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).

◆ VDAC_IntSet()

void VDAC_IntSet ( VDAC_TypeDef *  vdac,
uint32_t  flags 
)
inline

Set one or more pending VDAC interrupts from SW.

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

◆ VDAC_PrescaleCalc()

uint32_t VDAC_PrescaleCalc ( uint32_t  vdacFreq,
bool  syncMode,
uint32_t  hfperFreq 
)

Calculate the prescaler value used to determine 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. The input clock is HFPERCLK/HFPERCCLK when VDAC synchronous mode is selected, or an internal oscillator of 10 MHz +/- 20% when asynchronous mode is selected.

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.
Parameters
[in]vdacFreqVDAC frequency target. The frequency will automatically be adjusted to be below maximum allowed VDAC clock.
[in]syncModeSet to true if you intend to use VDAC in synchronous mode.
[in]hfperFreqFrequency in Hz of HFPERCLK/HFPERCCLK oscillator. Set to 0 to use the currently defined HFPERCLK/HFPERCCLK clock setting. This parameter is only used when syncMode is set to true.
Returns
A prescaler value to use for VDAC to achieve a clock value less than or equal to vdacFreq.

◆ VDAC_Reset()

void VDAC_Reset ( VDAC_TypeDef *  vdac)

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

Parameters
[in]vdacA pointer to the VDAC peripheral register block.

Macro Definition Documentation

◆ VDAC_INIT_DEFAULT

#define VDAC_INIT_DEFAULT
Value:
{ \
true, /* Use main output path calibration values. */ \
false, /* Use synchronous clock mode. */ \
false, /* Turn off between sample off conversions.*/ \
vdacRefresh8, /* Refresh every 8th cycle. */ \
0, /* No prescaling. */ \
vdacRef1V25Ln, /* 1.25 V internal low noise reference. */ \
false, /* Do not reset prescaler on CH 0 start. */ \
false, /* VDAC output enable always on. */ \
false, /* Disable sine mode. */ \
false /* Single ended mode. */ \
}

Default configuration for VDAC initialization structure.

◆ VDAC_INITCHANNEL_DEFAULT

#define VDAC_INITCHANNEL_DEFAULT
Value:
{ \
false, /* Leave channel disabled when initialization is done. */ \
vdacPrsSelCh0, /* PRS CH 0 triggers conversion. */ \
false, /* Treat PRS channel as a synchronous signal. */ \
vdacTrigModeSw, /* Conversion trigged by CH0DATA or COMBDATA write. */ \
false, /* Channel conversion set to continuous. */ \
}

Default configuration for VDAC channel initialization structure.

Enumeration Type Documentation

◆ VDAC_Refresh_TypeDef

enum VDAC_Refresh_TypeDef

Channel refresh period.

Enumerator
vdacRefresh8 

Refresh every 8 clock cycles.

vdacRefresh16 

Refresh every 16 clock cycles.

vdacRefresh32 

Refresh every 32 clock cycles.

vdacRefresh64 

Refresh every 64 clock cycles.

◆ VDAC_Ref_TypeDef

enum VDAC_Ref_TypeDef

Reference voltage for VDAC.

Enumerator
vdacRef1V25Ln 

Internal low noise 1.25 V band gap reference.

vdacRef2V5Ln 

Internal low noise 2.5 V band gap reference.

vdacRef1V25 

Internal 1.25 V band gap reference.

vdacRef2V5 

Internal 2.5 V band gap reference.

vdacRefAvdd 

AVDD reference.

vdacRefExtPin 

External pin reference.

◆ VDAC_PrsSel_TypeDef

enum VDAC_PrsSel_TypeDef

Peripheral Reflex System signal used to trigger VDAC channel conversion.

Enumerator
vdacPrsSelCh0 

PRS ch 0 triggers conversion.

vdacPrsSelCh1 

PRS ch 1 triggers conversion.

vdacPrsSelCh2 

PRS ch 2 triggers conversion.

vdacPrsSelCh3 

PRS ch 3 triggers conversion.

vdacPrsSelCh4 

PRS ch 4 triggers conversion.

vdacPrsSelCh5 

PRS ch 5 triggers conversion.

vdacPrsSelCh6 

PRS ch 6 triggers conversion.

vdacPrsSelCh7 

PRS ch 7 triggers conversion.

vdacPrsSelCh8 

PRS ch 8 triggers conversion.

vdacPrsSelCh9 

PRS ch 9 triggers conversion.

vdacPrsSelCh10 

PRS ch 10 triggers conversion.

vdacPrsSelCh11 

PRS ch 11 triggers conversion.

◆ VDAC_TrigMode_TypeDef

enum VDAC_TrigMode_TypeDef

Channel conversion trigger mode.

Enumerator
vdacTrigModeSw 

Channel is triggered by CHnDATA or COMBDATA write.

vdacTrigModePrs 

Channel is triggered by PRS input.

vdacTrigModeRefresh 

Channel is triggered by Refresh timer.

vdacTrigModeSwPrs 

Channel is triggered by CHnDATA/COMBDATA write or PRS input.

vdacTrigModeSwRefresh 

Channel is triggered by CHnDATA/COMBDATA write or Refresh timer.

vdacTrigModeLesense 

Channel is triggered by LESENSE.