Overview

The MCUXpresso SDK provides a peripheral driver for the Pulse Width Modulation (PWM) module of MCUXpresso SDK devices.

The function PWM_Init() initializes the PWM with a specified configurations. The function PWM_GetDefaultConfig() gets the default configurations.The initialization function configures the PWM for the requested register update mode for registers with buffers.

The function PWM_Deinit() disables the PWM counter and turns off the module clock.

Typical use case

PWM output

Output PWM signal on PWM3 module with different dutycycles. Periodically update the PWM signal duty cycle. Refer to the driver examples codes located at <SDK_ROOT>/boards/<BOARD>/driver_examples/pwm

Enumerations
enum	pwm_clock_source_t { kPWM_PeripheralClock = 1U, kPWM_HighFrequencyClock, kPWM_LowFrequencyClock }
	PWM clock source select. More...

enum	pwm_fifo_water_mark_t { kPWM_FIFOWaterMark_1 = 0U, kPWM_FIFOWaterMark_2, kPWM_FIFOWaterMark_3, kPWM_FIFOWaterMark_4 }
	PWM FIFO water mark select. More...

enum	pwm_byte_data_swap_t { kPWM_ByteNoSwap = 0U, kPWM_ByteSwap }
	PWM byte data swap select. More...

enum	pwm_half_word_data_swap_t { kPWM_HalfWordNoSwap = 0U, kPWM_HalfWordSwap }
	PWM half-word data swap select. More...

enum	pwm_output_configuration_t { kPWM_SetAtRolloverAndClearAtcomparison = 0U, kPWM_ClearAtRolloverAndSetAtcomparison, kPWM_NoConfigure }
	PWM Output Configuration. More...

enum	pwm_sample_repeat_t { kPWM_EachSampleOnce = 0u, kPWM_EachSampletwice, kPWM_EachSampleFourTimes, kPWM_EachSampleEightTimes }
	PWM FIFO sample repeat It determines the number of times each sample from the FIFO is to be used. More...

enum	pwm_interrupt_enable_t { kPWM_FIFOEmptyInterruptEnable = (1U << 0), kPWM_RolloverInterruptEnable = (1U << 1), kPWM_CompareInterruptEnable = (1U << 2) }
	List of PWM interrupt options. More...

enum	pwm_status_flags_t { kPWM_FIFOEmptyFlag = (1U << 3), kPWM_RolloverFlag = (1U << 4), kPWM_CompareFlag = (1U << 5), kPWM_FIFOWriteErrorFlag }
	List of PWM status flags. More...

enum	pwm_fifo_available_t { kPWM_NoDataInFIFOFlag = 0U, kPWM_OneWordInFIFOFlag, kPWM_TwoWordsInFIFOFlag, kPWM_ThreeWordsInFIFOFlag, kPWM_FourWordsInFIFOFlag }
	List of PWM FIFO available. More...

Functions
static void	PWM_SoftwareReset (PWM_Type *base)
	Sofrware reset. More...

static void	PWM_SetPeriodValue (PWM_Type *base, uint32_t value)
	Sets the PWM period value. More...

static uint32_t	PWM_GetPeriodValue (PWM_Type *base)
	Gets the PWM period value. More...

static uint32_t	PWM_GetCounterValue (PWM_Type *base)
	Gets the PWM counter value. More...

Driver version
#define	FSL_PWM_DRIVER_VERSION (MAKE_VERSION(2, 0, 0))
	Version 2.0.0.

Initialization and deinitialization
status_t	PWM_Init (PWM_Type base, const pwm_config_t config)
	Ungates the PWM clock and configures the peripheral for basic operation. More...

void	PWM_Deinit (PWM_Type *base)
	Gate the PWM submodule clock. More...

void	PWM_GetDefaultConfig (pwm_config_t *config)
	Fill in the PWM config struct with the default settings. More...

PWM start and stop.
static void	PWM_StartTimer (PWM_Type *base)
	Starts the PWM counter when the PWM is enabled. More...

static void	PWM_StopTimer (PWM_Type *base)
	Stops the PWM counter when the pwm is disabled. More...

Interrupt Interface
static void	PWM_EnableInterrupts (PWM_Type *base, uint32_t mask)
	Enables the selected PWM interrupts. More...

static void	PWM_DisableInterrupts (PWM_Type *base, uint32_t mask)
	Disables the selected PWM interrupts. More...

static uint32_t	PWM_GetEnabledInterrupts (PWM_Type *base)
	Gets the enabled PWM interrupts. More...

Status Interface
static uint32_t	PWM_GetStatusFlags (PWM_Type *base)
	Gets the PWM status flags. More...

static void	PWM_clearStatusFlags (PWM_Type *base, uint32_t mask)
	Clears the PWM status flags. More...

static uint32_t	PWM_GetFIFOAvailable (PWM_Type *base)
	Gets the PWM FIFO available. More...

Sample Interface
static void	PWM_SetSampleValue (PWM_Type *base, uint32_t value)
	Sets the PWM sample value. More...

static uint32_t	PWM_GetSampleValue (PWM_Type *base)
	Gets the PWM sample value. More...

Enumeration Type Documentation

enum pwm_clock_source_t

Enumerator
kPWM_PeripheralClock	The Peripheral clock is used as the clock.
kPWM_HighFrequencyClock	High-frequency reference clock is used as the clock.
kPWM_LowFrequencyClock	Low-frequency reference clock(32KHz) is used as the clock.

enum pwm_fifo_water_mark_t

Sets the data level at which the FIFO empty flag will be set

Enumerator
kPWM_FIFOWaterMark_1	FIFO empty flag is set when there are more than or equal to 1 empty slots.
kPWM_FIFOWaterMark_2	FIFO empty flag is set when there are more than or equal to 2 empty slots.
kPWM_FIFOWaterMark_3	FIFO empty flag is set when there are more than or equal to 3 empty slots.
kPWM_FIFOWaterMark_4	FIFO empty flag is set when there are more than or equal to 4 empty slots.

enum pwm_byte_data_swap_t

It determines the byte ordering of the 16-bit data when it goes into the FIFO from the sample register.

Enumerator
kPWM_ByteNoSwap	byte ordering remains the same
kPWM_ByteSwap	byte ordering is reversed

enum pwm_half_word_data_swap_t

Enumerator
kPWM_HalfWordNoSwap	Half word swapping does not take place.
kPWM_HalfWordSwap	Half word from write data bus are swapped.

enum pwm_output_configuration_t

Enumerator
kPWM_SetAtRolloverAndClearAtcomparison	Output pin is set at rollover and cleared at comparison.
kPWM_ClearAtRolloverAndSetAtcomparison	Output pin is cleared at rollover and set at comparison.
kPWM_NoConfigure	PWM output is disconnected.

enum pwm_sample_repeat_t

Enumerator
kPWM_EachSampleOnce	Use each sample once.
kPWM_EachSampletwice	Use each sample twice.
kPWM_EachSampleFourTimes	Use each sample four times.
kPWM_EachSampleEightTimes	Use each sample eight times.

enum pwm_interrupt_enable_t

Enumerator
kPWM_FIFOEmptyInterruptEnable	This bit controls the generation of the FIFO Empty interrupt.
kPWM_RolloverInterruptEnable	This bit controls the generation of the Rollover interrupt.
kPWM_CompareInterruptEnable	This bit controls the generation of the Compare interrupt.

enum pwm_status_flags_t

Enumerator
kPWM_FIFOEmptyFlag	This bit indicates the FIFO data level in comparison to the water level set by FWM field in the control register.
kPWM_RolloverFlag	This bit shows that a roll-over event has occurred.
kPWM_CompareFlag	This bit shows that a compare event has occurred.
kPWM_FIFOWriteErrorFlag	This bit shows that an attempt has been made to write FIFO when it is full.

enum pwm_fifo_available_t

Enumerator
kPWM_NoDataInFIFOFlag	No data available.
kPWM_OneWordInFIFOFlag	1 word of data in FIFO
kPWM_TwoWordsInFIFOFlag	2 word of data in FIFO
kPWM_ThreeWordsInFIFOFlag	3 word of data in FIFO
kPWM_FourWordsInFIFOFlag	4 word of data in FIFO

Function Documentation

status_t PWM_Init	(	PWM_Type *	base,
		const pwm_config_t *	config
	)

Note: This API should be called at the beginning of the application using the PWM driver.

Parameters

base	PWM peripheral base address
config	Pointer to user's PWM config structure.

Returns: kStatus_Success means success; else failed.

void PWM_Deinit ( PWM_Type * base )

Parameters

base	PWM peripheral base address

void PWM_GetDefaultConfig ( pwm_config_t * config )

The default values are:

*   config->enableStopMode = false;
*   config->enableDozeMode = false;
*   config->enableWaitMode = false;
*   config->enableDozeMode = false;
*   config->clockSource = kPWM_LowFrequencyClock;
*   config->prescale = 0U;
*   config->outputConfig = kPWM_SetAtRolloverAndClearAtcomparison;
*   config->fifoWater = kPWM_FIFOWaterMark_2;
*   config->sampleRepeat = kPWM_EachSampleOnce;
*   config->byteSwap = kPWM_ByteNoSwap;
*   config->halfWordSwap = kPWM_HalfWordNoSwap;
* 

Parameters

config Pointer to user's PWM config structure.

static void PWM_StartTimer ( PWM_Type * base )

inlinestatic

When the PWM is enabled, it begins a new period, the output pin is set to start a new period while the prescaler and counter are released and counting begins.

Parameters

base	PWM peripheral base address

static void PWM_StopTimer ( PWM_Type * base )

inlinestatic

Parameters

base	PWM peripheral base address

static void PWM_SoftwareReset ( PWM_Type * base )

inlinestatic

PWM is reset when this bit is set to 1. It is a self clearing bit. Setting this bit resets all the registers to their reset values except for the STOPEN, DOZEN, WAITEN, and DBGEN bits in this control register.

Parameters

base	PWM peripheral base address

static void PWM_EnableInterrupts	(	PWM_Type *	base,
		uint32_t	mask
	)

inlinestatic

Parameters

base	PWM peripheral base address
mask	The interrupts to enable. This is a logical OR of members of the enumeration pwm_interrupt_enable_t

static void PWM_DisableInterrupts	(	PWM_Type *	base,
		uint32_t	mask
	)

inlinestatic

Parameters

base	PWM peripheral base address
mask	The interrupts to disable. This is a logical OR of members of the enumeration pwm_interrupt_enable_t

static uint32_t PWM_GetEnabledInterrupts ( PWM_Type * base )

inlinestatic

Parameters

base	PWM peripheral base address

Returns: The enabled interrupts. This is the logical OR of members of the enumeration pwm_interrupt_enable_t

static uint32_t PWM_GetStatusFlags ( PWM_Type * base )

inlinestatic

Parameters

base	PWM peripheral base address

Returns: The status flags. This is the logical OR of members of the enumeration pwm_status_flags_t

static void PWM_clearStatusFlags	(	PWM_Type *	base,
		uint32_t	mask
	)

inlinestatic

Parameters

base	PWM peripheral base address
mask	The status flags to clear. This is a logical OR of members of the enumeration pwm_status_flags_t

static uint32_t PWM_GetFIFOAvailable ( PWM_Type * base )

inlinestatic

Parameters

base	PWM peripheral base address

Returns: The status flags. This is the logical OR of members of the enumeration pwm_fifo_available_t

static void PWM_SetSampleValue	(	PWM_Type *	base,
		uint32_t	value
	)

inlinestatic

Parameters

base	PWM peripheral base address
mask	The sample value. This is the input to the 4x16 FIFO. The value in this register denotes the value of the sample being currently used.

static uint32_t PWM_GetSampleValue ( PWM_Type * base )

inlinestatic

Parameters

base	PWM peripheral base address

Returns: The sample value. It can be read only when the PWM is enable.

static void PWM_SetPeriodValue	(	PWM_Type *	base,
		uint32_t	value
	)

inlinestatic

Parameters

base	PWM peripheral base address
mask	The period value. The PWM period register (PWM_PWMPR) determines the period of the PWM output signal. Writing 0xFFFF to this register will achieve the same result as writing 0xFFFE. PWMO (Hz) = PCLK(Hz) / (period +2)

static uint32_t PWM_GetPeriodValue ( PWM_Type * base )

inlinestatic

Parameters

base	PWM peripheral base address

Returns: The period value. The PWM period register (PWM_PWMPR) determines the period of the PWM output signal.

static uint32_t PWM_GetCounterValue ( PWM_Type * base )

inlinestatic

Parameters

base	PWM peripheral base address

Returns: The counter value. The current count value.

Overview

Typical use case

PWM output

Enumerations

Functions

Driver version

Initialization and deinitialization

PWM start and stop.

Interrupt Interface

Status Interface

Sample Interface

Enumeration Type Documentation

Function Documentation