Detailed Description

ADCBuf driver implementation for a MSP432E4 analog-to-digital converter.

Overview

This driver takes n samples using the ADC and stores the results in a buffer. This implementation supports both ADCBuf_RECURRENCE_MODE_ONE_SHOT and ADCBuf_RECURRENCE_MODE_CONTINUOUS. The ADCBuf_MSP432E4 driver supports use of both ADC peripherals and their sample sequencers.

General Behavior

The MSP342E4 microcontroller has two ADC modules and each ADC module has four sample sequencers, SS0-SS3, that control and capture sample data. Sequencer priority can be initialized in ADCBufMSP432E4_HWAttrsV1 by creating an array that holds the corresponding ADCBufMSP432E4_SequencePriorities.

To initialize the sequencers, in the board file "MSP_EXP432E401Y.c"/board.h

Specify the sequencer to use by setting ".adcSequence" in the array ADCBufMSP432E4_Channels for each channel/sequencer combination needed.
Change the sequencer priority for each sequencer to be used in the array ADCBufMSP432E4_SequencePriorities.

Sequencer Priorities - ADCBufMSP432E4_SequencePriorities

static ADCBufMSP432E4_SequencePriorities seqPriorities[ADCBufMSP432E4_SEQUENCER_COUNT] = {
    ADCBufMSP432E4_Priority_0,
    ADCBufMSP432E4_Seq_Disable,
    ADCBufMSP432E4_Seq_Disable,
    ADCBufMSP432E4_Seq_Disable
};

The MSP432E4 ADC sample sequencers can be triggered by several different types of software and hardware events. The driver currently only supports ADCBufMSP432E4_SOFTWARE_AUTOMATIC_TRIGGER and ADCBufMSP432E4_TIMER_TRIGGER trigger sources. Multiple sequencers can share the same trigger source. An unique ADCBufMSP432E4_TriggerSource array can be defined for each ADCBuf instance. That is, each ADCBufMSP432E4_HWAttrsV1.adcTriggerSource can point to a unique ADCBufMSP432E4_TriggerSource array.

The application is responsible for defining a ADCBufMSP432E4_Channels array. Each index corresponds to a ADC channel configuration. A unique ADCBufMSP432E4_Channels array can be defined for each ADCBuf instance. That is, each ADCBufMSP432E4_HWAttrsV1.channelSetting can point to a unique ADCBufMSP432E4_Channels array.

The ADCBufMSP432E4_Channels array lets the user select the ADCBufMSP432E4_Sequencer, ADCBufMSP432E4_DifferentialMode, the differential pins if needed, MSP432E4 specific ADC modes like ADCBufMSP432E4_TEMPERATURE_MODE that let the user configure the internal temperature mode

## Channel section - ADCBufMSP432E4_Channels

ADCBufMSP432E4_Channels adcBuf0MSP432E4Channels[ADCBUF0CHANNELCOUNT] = {
{
    .adcPin = ADCBufMSP432E4_PE_3_A0,
    .adcSequence = ADCBufMSP432E4_Seq_0,
    .adcInputMode = ADCBufMSP432E4_SINGLE_ENDED,
    .adcDifferentialPin = ADCBufMSP432E4_PIN_NONE,
    .adcInternalSource = ADCBufMSP432E4_INTERNAL_SOURCE_MODE_OFF,
    .refVoltage = 3300000
},
{
    .adcPin = ADCBufMSP432E4_PE_2_A1,
    .adcSequence = ADCBufMSP432E4_Seq_1,
    .adcInputMode = ADCBufMSP432E4_SINGLE_ENDED,
    .adcDifferentialPin = ADCBufMSP432E4_PIN_NONE,
    .adcInternalSource = ADCBufMSP432E4_INTERNAL_SOURCE_MODE_OFF,
    .refVoltage = 3300000
},

Please refer to ADCBufMSP432E4_HWAttrsV1 structure for other hardware dependent configuration settings Some examples include voltage reference source selection and optional DMA usage.

This driver supports various modes of operation and sampling. ADCBufMSP432E4_HWAttrsV1.useDMA can be set to 1 to improve performance. Additionally, samples can be performed using ADCBufMSP432E4_DIFFERENTIAL or ADCBufMSP432E4_TEMPERATURE_MODE modes.

In the application,

Call ADCBuf_init() once per ADC module.
Each ADC module requires a separate ADCBuf_open() call.
Create and initialize "ADCBuf_Conversion" object for each sequencer.
To make each sequencer sample multiple channels, create the conversion object as an array, example ADCBuf_Conversion continuousConversion[2] and initialize each channel within the conversion object.

Refer to ADCBuf.h for a complete description of APIs & example use.

#include <stdint.h>
#include <stdbool.h>
#include <ti/drivers/ADCBuf.h>
#include <ti/drivers/dpl/HwiP.h>
#include <ti/drivers/dpl/SemaphoreP.h>
#include <ti/drivers/dma/UDMAMSP432E4.h>
#include <ti/devices/msp432e4/driverlib/adc.h>

Include dependency graph for ADCBufMSP432E4.h:

Go to the source code of this file.

Data Structures
struct	ADCBufMSP432E4_ParamsExtension
	MSP432E4 ADCBuf_Params Parameter Extensions. More...

struct	ADCBufMSP432E4_Channels
	ADCBufMSP432E4 Channel Settings. More...

struct	ADCBufMSP432E4_HWAttrsV1
	ADCBufMSP432E4 Hardware attributes. More...

struct	ADCBufMSP432E4_Object

Macros
#define	MSP432E4_NUM_ADC_CHANNELS (24)

#define	ADCBufMSP432E4_SEQUENCER_COUNT 4

PB4, Analog Channel 10
#define	ADCBufMSP432E4_PB_4_A10 ((10 << 16) \| 0x5910)

PB5, Analog Channel 11
#define	ADCBufMSP432E4_PB_5_A11 ((11 << 16) \| 0x5920)

PD0, Analog Channel 15
#define	ADCBufMSP432E4_PD_0_A15 ((15 << 16) \| 0x5B01)

PD1, Analog Channel 14
#define	ADCBufMSP432E4_PD_1_A14 ((14 << 16) \| 0x5B02)

PD2, Analog Channel 13
#define	ADCBufMSP432E4_PD_2_A13 ((13 << 16) \| 0x5B04)

PD3, Analog Channel 12
#define	ADCBufMSP432E4_PD_3_A12 ((12 << 16) \| 0x5B08)

PD4, Analog Channel 7
#define	ADCBufMSP432E4_PD_4_A7 ((7 << 16) \| 0x5B10)

PD5, Analog Channel 6
#define	ADCBufMSP432E4_PD_5_A6 ((6 << 16) \| 0x5B20)

PD6, Analog Channel 5
#define	ADCBufMSP432E4_PD_6_A5 ((5 << 16) \| 0x5B40)

PD7, Analog Channel 4
#define	ADCBufMSP432E4_PD_7_A4 ((4 << 16) \| 0x5B80)

PE0, Analog Channel 3
#define	ADCBufMSP432E4_PE_0_A3 ((3 << 16) \| 0x5C01)

PE1, Analog Channel 2
#define	ADCBufMSP432E4_PE_1_A2 ((2 << 16) \| 0x5C02)

PE2, Analog Channel 1
#define	ADCBufMSP432E4_PE_2_A1 ((1 << 16) \| 0x5C04)

PE3, Analog Channel 0
#define	ADCBufMSP432E4_PE_3_A0 ((0 << 16) \| 0x5C08)

PE4, Analog Channel 9
#define	ADCBufMSP432E4_PE_4_A9 ((9 << 16) \| 0x5C10)

PE5, Analog Channel 8
#define	ADCBufMSP432E4_PE_5_A8 ((8 << 16) \| 0x5C20)

PE6, Analog Channel 20
#define	ADCBufMSP432E4_PE_6_A20 (((20-16) << 16) \| 0x5C40 \| 0x01000000)

PE7, Analog Channel 21
#define	ADCBufMSP432E4_PE_7_A21 (((21-16) << 16) \| 0x5C80 \| 0x01000000)

PK0, Analog Channel 16
#define	ADCBufMSP432E4_PK_0_A16 (((16-16) << 16) \| 0x6101 \| 0x01000000)

PK1, Analog Channel 17
#define	ADCBufMSP432E4_PK_1_A17 (((17-16) << 16) \| 0x6102 \| 0x01000000)

PK2, Analog Channel 18
#define	ADCBufMSP432E4_PK_2_A18 (((18-16) << 16) \| 0x6104 \| 0x01000000)

PK3, Analog Channel 19
#define	ADCBufMSP432E4_PK_3_A19 (((19-16) << 16) \| 0x6108 \| 0x01000000)

PP6, Analog Channel 23
#define	ADCBufMSP432E4_PP_6_A23 (((23-16) << 16) \| 0x6540 \| 0x01000000)

PP7, Analog Channel 22
#define	ADCBufMSP432E4_PP_7_A22 (((22-16) << 16) \| 0x6580 \| 0x01000000)

PIN NONE.
#define	ADCBufMSP432E4_PIN_NONE 0

Enumerations
enum	ADCBufMSP432E4_SequencePriorities { ADCBufMSP432E4_Priority_0 = 0, ADCBufMSP432E4_Priority_1 = 1, ADCBufMSP432E4_Priority_2 = 2, ADCBufMSP432E4_Priority_3 = 3, ADCBufMSP432E4_Seq_Disable = 4 }
	ADCBufMSP432E4 Sequencer Priorities. More...

enum	ADCBufMSP432E4_Sequencer { ADCBufMSP432E4_Seq_0 = 0, ADCBufMSP432E4_Seq_1 = 1, ADCBufMSP432E4_Seq_2 = 2, ADCBufMSP432E4_Seq_3 = 3 }
	ADCBufMSP432E4 Sequencer. More...

enum	ADCBufMSP432E4_InternalSourceMode { ADCBufMSP432E4_INTERNAL_SOURCE_MODE_OFF = 0, ADCBufMSP432E4_TEMPERATURE_MODE = ADC_CTL_TS }
	ADCBufMSP432E4 Internal Source Mode. More...

enum	ADCBufMSP432E4_DifferentialMode { ADCBufMSP432E4_SINGLE_ENDED = 0, ADCBufMSP432E4_DIFFERENTIAL = ADC_CTL_D }
	ADCBufMSP432E4 Differential Mode. More...

enum	ADCBufMSP432E4_TriggerSource { ADCBufMSP432E4_SOFTWARE_AUTOMATIC_TRIGGER = ADC_TRIGGER_ALWAYS, ADCBufMSP432E4_TIMER_TRIGGER = ADC_TRIGGER_TIMER }
	ADCBufMSP432E4 Trigger Source. More...

enum	ADCBufMSP432E4_Phase { ADCBufMSP432E4_Phase_Delay_0 = ADC_PHASE_0, ADCBufMSP432E4_Phase_Delay_22_5 = ADC_PHASE_22_5, ADCBufMSP432E4_Phase_Delay_45 = ADC_PHASE_45, ADCBufMSP432E4_Phase_Delay_67_5 = ADC_PHASE_67_5, ADCBufMSP432E4_Phase_Delay_90 = ADC_PHASE_90, ADCBufMSP432E4_Phase_Delay_112_5 = ADC_PHASE_112_5, ADCBufMSP432E4_Phase_Delay_135 = ADC_PHASE_135, ADCBufMSP432E4_Phase_Delay_157_5 = ADC_PHASE_157_5, ADCBufMSP432E4_Phase_Delay_180 = ADC_PHASE_180, ADCBufMSP432E4_Phase_Delay_202_5 = ADC_PHASE_202_5, ADCBufMSP432E4_Phase_Delay_225 = ADC_PHASE_225, ADCBufMSP432E4_Phase_Delay_247_5 = ADC_PHASE_247_5, ADCBufMSP432E4_Phase_Delay_270 = ADC_PHASE_270, ADCBufMSP432E4_Phase_Delay_292_5 = ADC_PHASE_292_5, ADCBufMSP432E4_Phase_Delay_315 = ADC_PHASE_315, ADCBufMSP432E4_Phase_Delay_337_5 = ADC_PHASE_337_5 }
	ADCBufMSP432E4 phase delay. More...

enum	ADCBufMSP432E4_SamplingDuration { ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_4 = ADC_CTL_SHOLD_4, ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_8 = ADC_CTL_SHOLD_8, ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_16 = ADC_CTL_SHOLD_16, ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_32 = ADC_CTL_SHOLD_32, ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_64 = ADC_CTL_SHOLD_64, ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_128 = ADC_CTL_SHOLD_128, ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_256 = ADC_CTL_SHOLD_256 }
	ADCMSP432E4 Sampling Duration. More...

enum	ADCBufMSP432E4_ReferenceSource { ADCBufMSP432E4_VREF_INTERNAL = ADC_REF_INT, ADCBufMSP432E4_VREF_EXTERNAL_3V = ADC_REF_EXT_3V }
	ADCBufMSP432E4 Reference Source. More...

Variables
const ADCBuf_FxnTable	ADCBufMSP432E4_fxnTable

Macro Definition Documentation

§ MSP432E4_NUM_ADC_CHANNELS

#define MSP432E4_NUM_ADC_CHANNELS (24)

Number of available ADC channels

§ ADCBufMSP432E4_SEQUENCER_COUNT

#define ADCBufMSP432E4_SEQUENCER_COUNT 4

Number of ADCBufMSP432E4_Sequencer per peripheral

Enumeration Type Documentation

§ ADCBufMSP432E4_SequencePriorities

enum ADCBufMSP432E4_SequencePriorities

ADCBufMSP432E4 Sequencer Priorities.

The application is responsible for defining a ADCBufMSP432E4_SequencePriorities array of ADCBufMSP432E4_SEQUENCER_COUNT length. Each index corresponds to one of the four sequencers respectively. A unique ADCBufMSP432E4_SequencePriorities array can be defined for each ADCBuf instance. That is, each ADCBufMSP432E4_HWAttrsV1.sequencePriority can point to a unique ADCBufMSP432E4_TriggerSource array.

A sequencer's priority is set by assigning its respective index to one of the ADCBufMSP432E4_SequencePriorities definitions. Multiple sequencers can share the same priority.

In the code example below, sequencer 0 and sequencer 2 have a priority of ADCBufMSP432E4_Priority_3. Sequencer 1 has a priority of ADCBufMSP432E4_Priority_0. Sequencer 3 is disabled.

static ADCBufMSP432E4_SequencePriorities sequencePriority[ADCBufMSP432E4_SEQUENCER_COUNT] = {
     ADCBufMSP432E4_Priority_3,
     ADCBufMSP432E4_Priority_0,
     ADCBufMSP432E4_Priority_3,
     ADCBufMSP432E4_Seq_Disable
};

Enumerator
ADCBufMSP432E4_Priority_0	ADC Sequencer priority 0, the highest priority
ADCBufMSP432E4_Priority_1	ADC Sequencer priority 1
ADCBufMSP432E4_Priority_2	ADC Sequencer priority 2
ADCBufMSP432E4_Priority_3	ADC Sequencer priority 3, the lowest priority
ADCBufMSP432E4_Seq_Disable	Disables a sequencer

§ ADCBufMSP432E4_Sequencer

enum ADCBufMSP432E4_Sequencer

ADCBufMSP432E4 Sequencer.

These fields are used to assign a sequencer to a channel by using the ADCBufMSP432E4_Channels.adcSequence field. Each sequencer can only support a limited number of ADC channels. It is the applications responsibility to ensure an appropriate number of channels are assigned to each sequencer. Assigning more ADC channels than a sequencer can support may lead to undefined behavior. Each ADC peripheral has dedicated sequencers.

Enumerator
ADCBufMSP432E4_Seq_0	ADC Sample Sequencer 0, can support up to 8 channels
ADCBufMSP432E4_Seq_1	ADC Sample Sequencer 1, can support up to 4 channels
ADCBufMSP432E4_Seq_2	ADC Sample Sequencer 2, can support up to 4 channels
ADCBufMSP432E4_Seq_3	ADC Sample Sequencer 3, can support 1 channel

§ ADCBufMSP432E4_InternalSourceMode

enum ADCBufMSP432E4_InternalSourceMode

ADCBufMSP432E4 Internal Source Mode.

These fields are used by ADCBufMSP432E4_Channels.adcInternalSource to specify if an internal source mode is selected. If using an internal source, ADCBufMSP432E4_Channels.adcInputMode must be set to ADCBufMSP432E4_SINGLE_ENDED.

Enumerator
ADCBufMSP432E4_INTERNAL_SOURCE_MODE_OFF	No internal source mode is used
ADCBufMSP432E4_TEMPERATURE_MODE	The ADC will sample the internal temperature. The ADCBufMSP432E4_Channels.adcPin should be set to ADCBufMSP432E4_PIN_NONE

§ ADCBufMSP432E4_DifferentialMode

enum ADCBufMSP432E4_DifferentialMode

ADCBufMSP432E4 Differential Mode.

These fields are used by ADCBufMSP432E4_Channels.adcInputMode to specify if a differential sampling mode is selected. If using the differential sampling mode, ADCBufMSP432E4_Channels.adcInternalSource must be set to ADCBufMSP432E4_INTERNAL_SOURCE_MODE_OFF.

Enumerator
ADCBufMSP432E4_SINGLE_ENDED	Use single ended sampling mode
ADCBufMSP432E4_DIFFERENTIAL	Use differential sampling mode. The ADC will measure the voltage difference between two channels. The user is responsible for setting the ADCBufMSP432E4_Channels.adcDifferentialPin.

§ ADCBufMSP432E4_TriggerSource

enum ADCBufMSP432E4_TriggerSource

ADCBufMSP432E4 Trigger Source.

The application is responsible for defining a ADCBufMSP432E4_TriggerSource array of ADCBufMSP432E4_SEQUENCER_COUNT length. Each index corresponds to one of the four sequencers respectively. A unique ADCBufMSP432E4_TriggerSource array can be defined for each ADCBuf instance. That is, each ADCBufMSP432E4_HWAttrsV1.adcTriggerSource can point to a unique ADCBufMSP432E4_TriggerSource array.

A sequencer's trigger source is set by assigning its respective index to one of the ADCBufMSP432E4_TriggerSource definitions. Multiple sequencers can share the same trigger source.

In the code example below, sequencer 0, sequencer 2 and sequencer 3 have a trigger source of ADCBufMSP432E4_TIMER_TRIGGER. Sequencer 1 has a trigger source of ADCBufMSP432E4_SOFTWARE_AUTOMATIC_TRIGGER.

static ADCBufMSP432E4_TriggerSource adcTriggerSource[ADCBufMSP432E4_SEQUENCER_COUNT] = {
     ADCBufMSP432E4_TIMER_TRIGGER,
     ADCBufMSP432E4_SOFTWARE_AUTOMATIC_TRIGGER,
     ADCBufMSP432E4_TIMER_TRIGGER,
     ADCBufMSP432E4_TIMER_TRIGGER
};

Enumerator
ADCBufMSP432E4_SOFTWARE_AUTOMATIC_TRIGGER	Automatically and continuously trigger ADC sampling. Precaution should be taken when using this mode with multiple sequencers. If the sequencer's priority using the software trigger is too high, it is possible to starve other lower priority sequencers. Generally, a sequencer using ADCBufMSP432E4_SOFTWARE_AUTOMATIC_TRIGGER should be set to the lowest priority.
ADCBufMSP432E4_TIMER_TRIGGER	Trigger ADC samples using a general purpose timer. When using both ADC peripherals, both must be initialized to use the same general purpose timer. The application is responsible for providing ADCBufMSP432E4_HWAttrsV1.adcTimerSource.

§ ADCBufMSP432E4_Phase

enum ADCBufMSP432E4_Phase

ADCBufMSP432E4 phase delay.

These fields are used by ADCBufMSP432E4_HWAttrsV1 to specify the phase delay between a trigger and the start of a sequence for the ADC module. By selecting a different phase delay for a pair of ADC modules (such as ADCBufMSP432E4_Phase_Delay_0 and ADCBufMSP432E4_Phase_Delay_180) and having each ADC module sample the same analog input, it is possible to increase the sampling rate of the analog input (with samples N, N+2, N+4, and so on, coming from the first ADC and samples N+1, N+3, N+5, and so on, coming from the second ADC). The ADC module has a single phase delay that is applied to all sample sequences within that module.

Enumerator
ADCBufMSP432E4_Phase_Delay_0	Use phase delay of 0 degrees
ADCBufMSP432E4_Phase_Delay_22_5	Use phase delay of 22.5 degrees
ADCBufMSP432E4_Phase_Delay_45	Use phase delay of 45 degrees
ADCBufMSP432E4_Phase_Delay_67_5	Use phase delay of 67.5 degrees
ADCBufMSP432E4_Phase_Delay_90	Use phase delay of 90 degrees
ADCBufMSP432E4_Phase_Delay_112_5	Use phase delay of 112.5 degrees
ADCBufMSP432E4_Phase_Delay_135	Use phase delay of 135 degrees
ADCBufMSP432E4_Phase_Delay_157_5	Use phase delay of 157.5 degrees
ADCBufMSP432E4_Phase_Delay_180	Use phase delay of 180 degrees
ADCBufMSP432E4_Phase_Delay_202_5	Use phase delay of 202.5 degrees
ADCBufMSP432E4_Phase_Delay_225	Use phase delay of 225 degrees
ADCBufMSP432E4_Phase_Delay_247_5	Use phase delay of 247.5 degrees
ADCBufMSP432E4_Phase_Delay_270	Use phase delay of 270 degrees
ADCBufMSP432E4_Phase_Delay_292_5	Use phase delay of 292.5 degrees
ADCBufMSP432E4_Phase_Delay_315	Use phase delay of 315 degrees
ADCBufMSP432E4_Phase_Delay_337_5	Use phase delay of 337.5 degrees

§ ADCBufMSP432E4_SamplingDuration

enum ADCBufMSP432E4_SamplingDuration

ADCMSP432E4 Sampling Duration.

These fields define the sample and hold time in the pulse width units. The application can specify the sampling duration at runtime using the ADCBufMSP432E4_ParamsExtension.samplingDuration field. The ADC clock is the same as the system clock.

Enumerator
ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_4	Use pulse width of 4 ADC clocks
ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_8	Use pulse width of 8 ADC clocks
ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_16	Use pulse width of 16 ADC clocks
ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_32	Use pulse width of 32 ADC clocks
ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_64	Use pulse width of 64 ADC clocks
ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_128	Use pulse width of 128 ADC clocks
ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_256	Use pulse width of 256 ADC clocks

§ ADCBufMSP432E4_ReferenceSource

enum ADCBufMSP432E4_ReferenceSource

ADCBufMSP432E4 Reference Source.

These fields are used by ADCBufMSP432E4_HWAttrsV1.refSource to specify the reference source for the ADC peripheral. This is therefore shared amongst all channels for an ADCBuf instance.

Enumerator
ADCBufMSP432E4_VREF_INTERNAL	Use internal reference voltage source of 3V.
ADCBufMSP432E4_VREF_EXTERNAL_3V	Use an external 3V reference source supplied to the AVREF pin.

Variable Documentation

§ ADCBufMSP432E4_fxnTable

const ADCBuf_FxnTable ADCBufMSP432E4_fxnTable