ADC - Analog to Digital Converter

Description

Analog to Digital Converter (ADC) Peripheral API.

This module contains functions to control the ADC peripheral of Silicon Labs 32-bit MCUs and SoCs. The ADC is used to convert analog signals into a digital representation.

Data Structures

struct ADC_Init_TypeDef
ADC initialization structure, common for single conversion and scan sequence.
struct ADC_InitScanInput_TypeDef
Scan input configuration.
struct ADC_InitScan_TypeDef
Scan sequence initialization structure.
struct ADC_InitSingle_TypeDef
Single conversion initialization structure.

Functions

void ADC_Init (ADC_TypeDef *adc, const ADC_Init_TypeDef *init)
Initialize ADC.
void ADC_InitScan (ADC_TypeDef *adc, const ADC_InitScan_TypeDef *init)
Initialize the ADC scan sequence.
void ADC_InitSingle (ADC_TypeDef *adc, const ADC_InitSingle_TypeDef *init)
Initialize the single ADC sample conversion.
uint8_t ADC_PrescaleCalc (uint32_t adcFreq, uint32_t hfperFreq)
Calculate the prescaler value used to determine the ADC clock.
void ADC_Reset (ADC_TypeDef *adc)
Reset ADC to a state that it was in after a hardware reset.
uint8_t ADC_TimebaseCalc (uint32_t hfperFreq)
Calculate a timebase value to get a timebase providing at least 1 us.
uint32_t ADC_DataSingleGet (ADC_TypeDef *adc)
Get a single conversion result.
uint32_t ADC_DataSinglePeek (ADC_TypeDef *adc)
Peek single conversion result.
uint32_t ADC_DataScanGet (ADC_TypeDef *adc)
Get a scan result.
uint32_t ADC_DataScanPeek (ADC_TypeDef *adc)
Peek scan result.
void ADC_IntClear (ADC_TypeDef *adc, uint32_t flags)
Clear one or more pending ADC interrupts.
void ADC_IntDisable (ADC_TypeDef *adc, uint32_t flags)
Disable one or more ADC interrupts.
void ADC_IntEnable (ADC_TypeDef *adc, uint32_t flags)
Enable one or more ADC interrupts.
uint32_t ADC_IntGet (ADC_TypeDef *adc)
Get pending ADC interrupt flags.
uint32_t ADC_IntGetEnabled (ADC_TypeDef *adc)
Get enabled and pending ADC interrupt flags.
void ADC_IntSet (ADC_TypeDef *adc, uint32_t flags)
Set one or more pending ADC interrupts from software.
void ADC_Start (ADC_TypeDef *adc, ADC_Start_TypeDef cmd)
Start scan sequence and/or single conversion.

Macros

#define ADC_INIT_DEFAULT
Default configuration for ADC initialization structure.
#define ADC_INITSCAN_DEFAULT
Default configuration for ADC scan initialization structure.
#define ADC_INITSINGLE_DEFAULT
Default configuration for ADC single conversion initialization structure.

Enumerations

enum ADC_AcqTime_TypeDef {
adcAcqTime1 = _ADC_SINGLECTRL_AT_1CYCLE,
adcAcqTime2 = _ADC_SINGLECTRL_AT_2CYCLES,
adcAcqTime4 = _ADC_SINGLECTRL_AT_4CYCLES,
adcAcqTime8 = _ADC_SINGLECTRL_AT_8CYCLES,
adcAcqTime16 = _ADC_SINGLECTRL_AT_16CYCLES,
adcAcqTime32 = _ADC_SINGLECTRL_AT_32CYCLES,
adcAcqTime64 = _ADC_SINGLECTRL_AT_64CYCLES,
adcAcqTime128 = _ADC_SINGLECTRL_AT_128CYCLES,
adcAcqTime256 = _ADC_SINGLECTRL_AT_256CYCLES
}
Acquisition time (in ADC clock cycles).
enum ADC_LPFilter_TypeDef {
adcLPFilterBypass = _ADC_CTRL_LPFMODE_BYPASS,
adcLPFilterRC = _ADC_CTRL_LPFMODE_RCFILT,
adcLPFilterDeCap = _ADC_CTRL_LPFMODE_DECAP
}
Lowpass filter mode.
enum ADC_OvsRateSel_TypeDef {
adcOvsRateSel2 = _ADC_CTRL_OVSRSEL_X2,
adcOvsRateSel4 = _ADC_CTRL_OVSRSEL_X4,
adcOvsRateSel8 = _ADC_CTRL_OVSRSEL_X8,
adcOvsRateSel16 = _ADC_CTRL_OVSRSEL_X16,
adcOvsRateSel32 = _ADC_CTRL_OVSRSEL_X32,
adcOvsRateSel64 = _ADC_CTRL_OVSRSEL_X64,
adcOvsRateSel128 = _ADC_CTRL_OVSRSEL_X128,
adcOvsRateSel256 = _ADC_CTRL_OVSRSEL_X256,
adcOvsRateSel512 = _ADC_CTRL_OVSRSEL_X512,
adcOvsRateSel1024 = _ADC_CTRL_OVSRSEL_X1024,
adcOvsRateSel2048 = _ADC_CTRL_OVSRSEL_X2048,
adcOvsRateSel4096 = _ADC_CTRL_OVSRSEL_X4096
}
Oversample rate select.
enum ADC_PRSSEL_TypeDef {
adcPRSSELCh0 = _ADC_SINGLECTRL_PRSSEL_PRSCH0,
adcPRSSELCh1 = _ADC_SINGLECTRL_PRSSEL_PRSCH1,
adcPRSSELCh2 = _ADC_SINGLECTRL_PRSSEL_PRSCH2,
adcPRSSELCh3 = _ADC_SINGLECTRL_PRSSEL_PRSCH3,
adcPRSSELCh4 = _ADC_SINGLECTRL_PRSSEL_PRSCH4,
adcPRSSELCh5 = _ADC_SINGLECTRL_PRSSEL_PRSCH5,
adcPRSSELCh6 = _ADC_SINGLECTRL_PRSSEL_PRSCH6,
adcPRSSELCh7 = _ADC_SINGLECTRL_PRSSEL_PRSCH7
}
Peripheral Reflex System signal used to trigger a single sample.
enum ADC_Ref_TypeDef {
adcRef1V25 = _ADC_SINGLECTRL_REF_1V25,
adcRef2V5 = _ADC_SINGLECTRL_REF_2V5,
adcRefVDD = _ADC_SINGLECTRL_REF_VDD,
adcRef5VDIFF = _ADC_SINGLECTRL_REF_5VDIFF,
adcRefExtSingle = _ADC_SINGLECTRL_REF_EXTSINGLE,
adcRef2xExtDiff = _ADC_SINGLECTRL_REF_2XEXTDIFF,
adcRef2xVDD = _ADC_SINGLECTRL_REF_2XVDD
}
Single and scan mode voltage references.
enum ADC_Res_TypeDef {
adcRes12Bit = _ADC_SINGLECTRL_RES_12BIT,
adcRes8Bit = _ADC_SINGLECTRL_RES_8BIT,
adcRes6Bit = _ADC_SINGLECTRL_RES_6BIT,
adcResOVS = _ADC_SINGLECTRL_RES_OVS
}
Sample resolution.
enum ADC_SingleInput_TypeDef {
adcSingleInputCh0 = _ADC_SINGLECTRL_INPUTSEL_CH0,
adcSingleInputCh1 = _ADC_SINGLECTRL_INPUTSEL_CH1,
adcSingleInputCh2 = _ADC_SINGLECTRL_INPUTSEL_CH2,
adcSingleInputCh3 = _ADC_SINGLECTRL_INPUTSEL_CH3,
adcSingleInputCh4 = _ADC_SINGLECTRL_INPUTSEL_CH4,
adcSingleInputCh5 = _ADC_SINGLECTRL_INPUTSEL_CH5,
adcSingleInputCh6 = _ADC_SINGLECTRL_INPUTSEL_CH6,
adcSingleInputCh7 = _ADC_SINGLECTRL_INPUTSEL_CH7,
adcSingleInputTemp = _ADC_SINGLECTRL_INPUTSEL_TEMP,
adcSingleInputVDDDiv3 = _ADC_SINGLECTRL_INPUTSEL_VDDDIV3,
adcSingleInputVDD = _ADC_SINGLECTRL_INPUTSEL_VDD,
adcSingleInputVSS = _ADC_SINGLECTRL_INPUTSEL_VSS,
adcSingleInputVrefDiv2 = _ADC_SINGLECTRL_INPUTSEL_VREFDIV2,
adcSingleInputDACOut0 = _ADC_SINGLECTRL_INPUTSEL_DAC0OUT0,
adcSingleInputDACOut1 = _ADC_SINGLECTRL_INPUTSEL_DAC0OUT1,
adcSingleInputATEST = 15,
adcSingleInputCh0Ch1 = _ADC_SINGLECTRL_INPUTSEL_CH0CH1,
adcSingleInputCh2Ch3 = _ADC_SINGLECTRL_INPUTSEL_CH2CH3,
adcSingleInputCh4Ch5 = _ADC_SINGLECTRL_INPUTSEL_CH4CH5,
adcSingleInputCh6Ch7 = _ADC_SINGLECTRL_INPUTSEL_CH6CH7,
adcSingleInputDiff0 = 4
}
Single sample input selection.
enum ADC_Start_TypeDef {
adcStartSingle = ADC_CMD_SINGLESTART,
adcStartScan = ADC_CMD_SCANSTART,
adcStartScanAndSingle = ADC_CMD_SCANSTART | ADC_CMD_SINGLESTART
}
ADC start command.
enum ADC_Warmup_TypeDef {
adcWarmupNormal = _ADC_CTRL_WARMUPMODE_NORMAL,
adcWarmupFastBG = _ADC_CTRL_WARMUPMODE_FASTBG,
adcWarmupKeepScanRefWarm = _ADC_CTRL_WARMUPMODE_KEEPSCANREFWARM,
adcWarmupKeepADCWarm = _ADC_CTRL_WARMUPMODE_KEEPADCWARM
}
Warm-up mode.

Function Documentation

◆ ADC_Init()

void ADC_Init ( ADC_TypeDef * adc,
const ADC_Init_TypeDef * init
)

Initialize ADC.

Initializes common parts for both single conversion and scan sequence. In addition, single and/or scan control configuration must be done. See ADC_InitSingle() and ADC_InitScan() respectively. For ADC architectures with the ADCn->SCANINPUTSEL register, use ADC_ScanSingleEndedInputAdd() to configure single-ended scan inputs or ADC_ScanDifferentialInputAdd() to configure differential scan inputs. ADC_ScanInputClear() is also provided for applications that need to update the input configuration.

Note
This function will stop any ongoing conversion.
Parameters
[in] adc A pointer to the ADC peripheral register block.
[in] init A pointer to the ADC initialization structure.

◆ ADC_InitScan()

void ADC_InitScan ( ADC_TypeDef * adc,
const ADC_InitScan_TypeDef * init
)

Initialize the ADC scan sequence.

See ADC_Start() for starting a scan sequence.

When selecting an external reference, the gain and offset calibration must be set explicitly (CAL register). For other references, the calibration is updated with values defined during manufacturing. For ADC architectures with the ADCn->SCANINPUTSEL register, use ADC_ScanSingleEndedInputAdd() to configure single-ended scan inputs or ADC_ScanDifferentialInputAdd() to configure differential scan inputs. ADC_ScanInputClear() is also provided for applications that need to update the input configuration.

Note
This function will stop any ongoing scan sequence.
Parameters
[in] adc A pointer to the ADC peripheral register block.
[in] init A pointer to the ADC initialization structure.

◆ ADC_InitSingle()

void ADC_InitSingle ( ADC_TypeDef * adc,
const ADC_InitSingle_TypeDef * init
)

Initialize the single ADC sample conversion.

See ADC_Start() for starting a single conversion.

When selecting an external reference, the gain and offset calibration must be set explicitly (CAL register). For other references, the calibration is updated with values defined during manufacturing.

Note
This function will stop any ongoing single conversion.
Parameters
[in] adc A pointer to the ADC peripheral register block.
[in] init A pointer to the ADC initialization structure.

◆ ADC_PrescaleCalc()

uint8_t ADC_PrescaleCalc ( uint32_t adcFreq,
uint32_t hfperFreq
)

Calculate the prescaler value used to determine the ADC clock.

The ADC clock is given by: (HFPERCLK or HFPERCCLK) / (prescale + 1).

Note
The return value is clamped to the maximum prescaler value that the hardware supports.
Parameters
[in] adcFreq ADC frequency wanted. The frequency will automatically be adjusted to a valid range according to the reference manual.
[in] hfperFreq Frequency in Hz of reference HFPER/HFPERC clock. Set to 0 to use currently defined HFPER/HFPERC clock setting.
Returns
A prescaler value to use for ADC in order to achieve a clock value <= adcFreq .

◆ ADC_Reset()

void ADC_Reset ( ADC_TypeDef * adc )

Reset ADC to a state that it was in after a hardware reset.

Note
The ROUTE register is NOT reset by this function to allow a centralized setup of this feature.
Parameters
[in] adc A pointer to ADC peripheral register block.

◆ ADC_TimebaseCalc()

uint8_t ADC_TimebaseCalc ( uint32_t hfperFreq )

Calculate a timebase value to get a timebase providing at least 1 us.

Parameters
[in] hfperFreq Frequency in Hz of the reference HFPER/HFPERC clock. Set to 0 to use currently defined HFPER/HFPERC clock setting.
Returns
A timebase value to use for ADC to achieve at least 1 us.

◆ ADC_DataSingleGet()

uint32_t ADC_DataSingleGet ( ADC_TypeDef * adc )
inline

Get a single conversion result.

Note
Check data valid flag before calling this function.
Parameters
[in] adc A pointer to the ADC peripheral register block.
Returns
Single conversion data.

◆ ADC_DataSinglePeek()

uint32_t ADC_DataSinglePeek ( ADC_TypeDef * adc )
inline

Peek single conversion result.

Note
Check data valid flag before calling this function.
Parameters
[in] adc A pointer to the ADC peripheral register block.
Returns
Single conversion data.

◆ ADC_DataScanGet()

uint32_t ADC_DataScanGet ( ADC_TypeDef * adc )
inline

Get a scan result.

Note
Check data valid flag before calling this function.
Parameters
[in] adc A pointer to the ADC peripheral register block.
Returns
Scan conversion data.

◆ ADC_DataScanPeek()

uint32_t ADC_DataScanPeek ( ADC_TypeDef * adc )
inline

Peek scan result.

Note
Check data valid flag before calling this function.
Parameters
[in] adc A pointer to the ADC peripheral register block.
Returns
Scan conversion data.

◆ ADC_IntClear()

void ADC_IntClear ( ADC_TypeDef * adc,
uint32_t flags
)
inline

Clear one or more pending ADC interrupts.

Parameters
[in] adc A pointer to the ADC peripheral register block.
[in] flags Pending ADC interrupt source to clear. Use a bitwise logic OR combination of valid interrupt flags for the ADC module (ADC_IF_nnn).

◆ ADC_IntDisable()

void ADC_IntDisable ( ADC_TypeDef * adc,
uint32_t flags
)
inline

Disable one or more ADC interrupts.

Parameters
[in] adc A pointer to the ADC peripheral register block.
[in] flags ADC interrupt sources to disable. Use a bitwise logic OR combination of valid interrupt flags for the ADC module (ADC_IF_nnn).

◆ ADC_IntEnable()

void ADC_IntEnable ( ADC_TypeDef * adc,
uint32_t flags
)
inline

Enable one or more ADC interrupts.

Note
Depending on use, a pending interrupt may already be set prior to enabling the interrupt. Consider using ADC_IntClear() prior to enabling if the pending interrupt should be ignored.
Parameters
[in] adc A pointer to the ADC peripheral register block.
[in] flags ADC interrupt sources to enable. Use a bitwise logic OR combination of valid interrupt flags for the ADC module (ADC_IF_nnn).

◆ ADC_IntGet()

uint32_t ADC_IntGet ( ADC_TypeDef * adc )
inline

Get pending ADC interrupt flags.

Note
This function does not clear event bits.
Parameters
[in] adc A pointer to the ADC peripheral register block.
Returns
ADC interrupt sources pending. A bitwise logic OR combination of valid interrupt flags for the ADC module (ADC_IF_nnn).

◆ ADC_IntGetEnabled()

uint32_t ADC_IntGetEnabled ( ADC_TypeDef * adc )
inline

Get enabled and pending ADC interrupt flags.

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

Parameters
[in] adc A pointer to the ADC peripheral register block.
Note
This function does not clear interrupt flags.
Returns
Pending and enabled ADC interrupt sources. The return value is the bitwise AND combination of
  • the OR combination of enabled interrupt sources in ADCx_IEN_nnn register (ADCx_IEN_nnn) and
  • the OR combination of valid interrupt flags of the ADC module (ADCx_IF_nnn).

◆ ADC_IntSet()

void ADC_IntSet ( ADC_TypeDef * adc,
uint32_t flags
)
inline

Set one or more pending ADC interrupts from software.

Parameters
[in] adc A pointer to the ADC peripheral register block.
[in] flags ADC interrupt sources to set to pending. Use a bitwise logic OR combination of valid interrupt flags for the ADC module (ADC_IF_nnn).

◆ ADC_Start()

void ADC_Start ( ADC_TypeDef * adc,
ADC_Start_TypeDef cmd
)
inline

Start scan sequence and/or single conversion.

Parameters
[in] adc A pointer to the ADC peripheral register block.
[in] cmd A command indicating which type of sampling to start.

Macro Definition Documentation

◆ ADC_INIT_DEFAULT

#define ADC_INIT_DEFAULT
Value:
{ \
adcOvsRateSel2, /* 2x oversampling (if enabled). */ \
adcLPFilterBypass, /* No input filter selected. */ \
adcWarmupNormal, /* ADC shutdown after each conversion. */ \
_ADC_CTRL_TIMEBASE_DEFAULT, /* Use hardware default value. */ \
_ADC_CTRL_PRESC_DEFAULT, /* Use hardware default value. */ \
false /* Do not use tailgate. */ \
}

Default configuration for ADC initialization structure.

◆ ADC_INITSCAN_DEFAULT

#define ADC_INITSCAN_DEFAULT
Value:
{ \
adcPRSSELCh0, /* PRS ch0 (if enabled). */ \
adcAcqTime1, /* 1 ADC_CLK cycle acquisition time. */ \
adcRef1V25, /* 1.25 V internal reference. */ \
adcRes12Bit, /* 12 bit resolution. */ \
0, /* No input selected. */ \
false, /* Single-ended input. */ \
false, /* PRS disabled. */ \
false, /* Right adjust. */ \
false, /* Deactivate conversion after one scan sequence. */ \
}

Default configuration for ADC scan initialization structure.

◆ ADC_INITSINGLE_DEFAULT

#define ADC_INITSINGLE_DEFAULT
Value:
{ \
adcPRSSELCh0, /* PRS ch0 (if enabled). */ \
adcAcqTime1, /* 1 ADC_CLK cycle acquisition time. */ \
adcRef1V25, /* 1.25 V internal reference. */ \
adcRes12Bit, /* 12 bit resolution. */ \
adcSingleInpCh0, /* CH0 input selected. */ \
false, /* Single-ended input. */ \
false, /* PRS disabled. */ \
false, /* Right adjust. */ \
false /* Deactivate conversion after one scan sequence. */ \
}

Default configuration for ADC single conversion initialization structure.

Enumeration Type Documentation

◆ ADC_AcqTime_TypeDef

enum ADC_AcqTime_TypeDef

Acquisition time (in ADC clock cycles).

Enumerator
adcAcqTime1

1 clock cycle.

adcAcqTime2

2 clock cycles.

adcAcqTime4

4 clock cycles.

adcAcqTime8

8 clock cycles.

adcAcqTime16

16 clock cycles.

adcAcqTime32

32 clock cycles.

adcAcqTime64

64 clock cycles.

adcAcqTime128

128 clock cycles.

adcAcqTime256

256 clock cycles.

◆ ADC_LPFilter_TypeDef

enum ADC_LPFilter_TypeDef

Lowpass filter mode.

Enumerator
adcLPFilterBypass

No filter or decoupling capacitor.

adcLPFilterRC

On-chip RC filter.

adcLPFilterDeCap

On-chip decoupling capacitor.

◆ ADC_OvsRateSel_TypeDef

enum ADC_OvsRateSel_TypeDef

Oversample rate select.

Enumerator
adcOvsRateSel2

2 samples per conversion result.

adcOvsRateSel4

4 samples per conversion result.

adcOvsRateSel8

8 samples per conversion result.

adcOvsRateSel16

16 samples per conversion result.

adcOvsRateSel32

32 samples per conversion result.

adcOvsRateSel64

64 samples per conversion result.

adcOvsRateSel128

128 samples per conversion result.

adcOvsRateSel256

256 samples per conversion result.

adcOvsRateSel512

512 samples per conversion result.

adcOvsRateSel1024

1024 samples per conversion result.

adcOvsRateSel2048

2048 samples per conversion result.

adcOvsRateSel4096

4096 samples per conversion result.

◆ ADC_PRSSEL_TypeDef

enum ADC_PRSSEL_TypeDef

Peripheral Reflex System signal used to trigger a single sample.

Enumerator
adcPRSSELCh0

PRS channel 0.

adcPRSSELCh1

PRS channel 1.

adcPRSSELCh2

PRS channel 2.

adcPRSSELCh3

PRS channel 3.

adcPRSSELCh4

PRS channel 4.

adcPRSSELCh5

PRS channel 5.

adcPRSSELCh6

PRS channel 6.

adcPRSSELCh7

PRS channel 7.

◆ ADC_Ref_TypeDef

enum ADC_Ref_TypeDef

Single and scan mode voltage references.

Using unshifted enumerations and or in ADC_CTRLX_VREFSEL_REG to select the extension register CTRLX_VREFSEL. ADC Reference

Enumerator
adcRef1V25

Internal 1.25 V reference.

adcRef2V5

Internal 2.5 V reference.

adcRefVDD

Buffered VDD.

adcRef5VDIFF

Internal differential 5 V reference.

adcRefExtSingle

Single-ended external reference from pin 6.

adcRef2xExtDiff

Differential external reference from pin 6 and 7.

adcRef2xVDD

Unbuffered 2xVDD.

◆ ADC_Res_TypeDef

enum ADC_Res_TypeDef

Sample resolution.

Enumerator
adcRes12Bit

12 bit sampling.

adcRes8Bit

8 bit sampling.

adcRes6Bit

6 bit sampling.

adcResOVS

Oversampling.

◆ ADC_SingleInput_TypeDef

enum ADC_SingleInput_TypeDef

Single sample input selection.

Enumerator
adcSingleInputCh0

Channel 0.

adcSingleInputCh1

Channel 1.

adcSingleInputCh2

Channel 2.

adcSingleInputCh3

Channel 3.

adcSingleInputCh4

Channel 4.

adcSingleInputCh5

Channel 5.

adcSingleInputCh6

Channel 6.

adcSingleInputCh7

Channel 7.

adcSingleInputTemp

Temperature reference.

adcSingleInputVDDDiv3

VDD divided by 3.

adcSingleInputVDD

VDD.

adcSingleInputVSS

VSS.

adcSingleInputVrefDiv2

Vref divided by 2.

adcSingleInputDACOut0

DAC output 0.

adcSingleInputDACOut1

DAC output 1.

adcSingleInputATEST

ATEST.

adcSingleInputCh0Ch1

Positive Ch0, negative Ch1.

adcSingleInputCh2Ch3

Positive Ch2, negative Ch3.

adcSingleInputCh4Ch5

Positive Ch4, negative Ch5.

adcSingleInputCh6Ch7

Positive Ch6, negative Ch7.

adcSingleInputDiff0

Differential 0.

◆ ADC_Start_TypeDef

enum ADC_Start_TypeDef

ADC start command.

Enumerator
adcStartSingle

Start a single conversion.

adcStartScan

Start a scan sequence.

adcStartScanAndSingle

Start a scan sequence and single conversion, typically used when tailgating a single conversion after a scan sequence.

◆ ADC_Warmup_TypeDef

enum ADC_Warmup_TypeDef

Warm-up mode.

Enumerator
adcWarmupNormal

ADC shutdown after each conversion.

adcWarmupFastBG

Do not warm up bandgap references.

adcWarmupKeepScanRefWarm

Reference selected for scan mode kept warm.

adcWarmupKeepADCWarm

ADC and reference selected for scan mode kept at warmup allowing continuous conversion.