Overview

The section describes the programming interface of the eFlexPWM Peripheral driver. The Pulse Width Modulator A (PWMA/eFlexPWM) module contains PWM sub modules, each of which is set up to control a single half-bridge power stage. Fault channel support is provided. This PWM module can generate various switching patterns, including highly sophisticated waveforms. It can be used to control all known Switched Mode Power Supplies (SMPS) topologies.

Initialization

To initialize the PWM driver, call the PWM_DRV_Init() function and pass the instance and sub module numbers of the relevant PWM. For instance, to use PWM0, pass a value of 0 to the initialization function. In addition, you should also pass a user configuration structure pwm_user_config_t, as shown here:

// PWM configuration structure for user
typedef struct PwmUserConfig {
    uint8_t Clock;
    uint8_t OutputTrigger;
    uint8_t Polarity;
    bool isFaultEnable;
} pwm_user_config_t;

Generate a PWM signal

The PWM calls the PWM_DRV_PwmStart() function to generate a PWM signal. Use this structure to configure different parameters related to this PWM signal:

typedef struct FtmPwmParam
typedef struct PwmParam
{
    uint32_t uFrequencyHZ;           

HAS TO BE UPDATED The mode options are kFtmEdgeAlignedPWM, kFtmCenterAlignedPWM and kFtmCombinedPWM. For edge mode, the options available are kFtmHighTrue and kFtmLowTrue. Specify the PWM signal frequency in Hertz and the duty cycle percentage (value between 0-100). When the PWM mode is kFtmCombinedPWM, specify a value for uFirstEdgeDelayPercent which delays the start of the PWM pulse.

Data Structures
struct	pwm_module_signal_setup_t
	Configuration structure for the user to define the PWM signal characteristics. More...

Macros
#define	FLEXPWM_NO_PWM_OUT_SIGNAL (0)
	Used to indicate that a particular pin in the submodule does NOT output a PWM signal.

Enumerations
enum	pwm_signal_type_t { kFlexPwmSignedCenterAligned = 0U, kFlexPwmCenterAligned, kFlexPwmSignedEdgeAligned, kFlexPwmEdgeAligned }
	PWM Signal Type options. More...

Functions
pwm_status_t	PWM_DRV_Init (uint32_t instance)
	Initializes the PWM module. More...

void	PWM_DRV_Deinit (uint32_t instance)
	Shuts down the PWM driver. More...

pwm_status_t	PWM_DRV_SetupPwm (uint32_t instance, pwm_module_t subModule, pwm_module_setup_t moduleSetupParams, pwm_module_signal_setup_t signalParams)
	Sets up the PWM signals from the FlewPWM module. More...

void	PWM_DRV_UpdatePwmSignal (uint32_t instance, pwm_module_t subModule, pwm_module_signal_setup_t *signalParams)
	Updates the PWM signal settings. More...

void	PWM_DRV_SetTriggerCmd (uint32_t instance, pwm_module_t subModule, pwm_val_regs_t trigger, bool activate)
	Enables or disables the PWM output trigger. More...

void	PWM_DRV_SetTriggerVal (uint32_t instance, pwm_module_t subModule, pwm_val_regs_t trigger, uint16_t triggerVal)
	Sets the PWM trigger value. More...

void	PWM_DRV_SetupFault (uint32_t instance, pwm_module_t subModule, pwm_fault_input_t faultNum, pwm_fault_setup_t *faultParams, bool pwmA, bool pwmB, bool pwmX)
	Sets up the PWM fault. More...

void	PWM_DRV_CounterStart (uint32_t instance, uint8_t value)
	Starts the PWM counter. More...

void	PWM_DRV_CounterStop (uint32_t instance, uint8_t value)
	Stops the PWM counter. More...

void	PWM_DRV_SetExternalClkFreq (uint32_t instance, uint32_t externalClkFreq)
	Provides the frequency of the external clock source. More...

Variables
PWM_Type *const	g_pwmBase [PWM_INSTANCE_COUNT]
	Table of base addresses for PWM instances. More...

const IRQn_Type	g_pwmCmpIrqId [FSL_FEATURE_PWM_CMP_INT_HANDLER_COUNT]
	Table to save PWM IRQ enumeration numbers defined in CMSIS header file. More...

Data Structure Documentation

struct pwm_module_signal_setup_t

Data Fields
uint32_t	pwmPeriod
	PWM period specified in microseconds.

pwm_signal_type_t	pwmType
	PWM type, edge or center, signed or unsigned.

uint32_t	pwmAPulseWidth
	PWM A pulse width specified in microseconds. More...

uint32_t	pwmBPulseWidth
	PWM B pulse width specified in microseconds. More...

bool	pwmAPolarity
	true: if output is to be inverted; false: if no output inversion.

bool	pwmBPolarity
	true: if output is to be inverted; false: if no output inversion.

Field Documentation

uint32_t pwm_module_signal_setup_t::pwmAPulseWidth

Specify FLEXPWM_NO_PWM_OUT_SIGNAL if no PWM output on this pin.

uint32_t pwm_module_signal_setup_t::pwmBPulseWidth

Specify FLEXPWM_NO_PWM_OUT_SIGNAL if no PWM output on this pin.

Enumeration Type Documentation

enum pwm_signal_type_t

Enumerator
kFlexPwmSignedCenterAligned	Signed center-aligned.
kFlexPwmCenterAligned	Unsigned cente-aligned.
kFlexPwmSignedEdgeAligned	Signed edge-aligned.
kFlexPwmEdgeAligned	Unsigned edge-aligned.

Function Documentation

pwm_status_t PWM_DRV_Init ( uint32_t instance )

Enables the module clocks and interrupts in the interrupt controller.

Parameters

instance Instance number of the PWM module.

Returns: kStatusPwmSuccess means success. Otherwise, means failure.

void PWM_DRV_Deinit ( uint32_t instance )

This function de-initializes the EflexPWM module and disables the clock for the submodules. It also disables the module-level interrupts.

Parameters

instance Instance number of the PWM module.

pwm_status_t PWM_DRV_SetupPwm	(	uint32_t	instance,
		pwm_module_t	subModule,
		pwm_module_setup_t *	moduleSetupParams,
		pwm_module_signal_setup_t *	signalParams
	)

The function initializes the submodule according to the parameters passed in by the user. The function also sets up the value compare registers to match the PWM signal requirements. If the dead time insertion logic is enabled, the pulse period is reduced by the dead time period specified by the user.

Parameters

instance	Instance number of the PWM module.
subModule	The FlexPWM submodule that is configured
moduleSetupParams	The initialization values used to set up the submodule
signalParams	Signal parameters which generate the submodules PWM signals

Returns: Returns an error if the requested submodule clock is incorrect, i.e., the request for kFlexPwmModule0 for submodule 0 or request for external clock without informing the driver of the external clock frequency by calling PWM_DVR_SetExternalClkFreq(). Success otherwise.

void PWM_DRV_UpdatePwmSignal	(	uint32_t	instance,
		pwm_module_t	subModule,
		pwm_module_signal_setup_t *	signalParams
	)

The function updates the PWM signal to the new value that is passed in. If the dead time insertion logic is enabled then the pulse period is reduced by the dead time period specified by the user.

Parameters

instance	Instance number of the PWM module.
subModule	The FlexPWM submodule that is configured
signalParams	Signal parameters which generate the submodules PWM signals

void PWM_DRV_SetTriggerCmd	(	uint32_t	instance,
		pwm_module_t	subModule,
		pwm_val_regs_t	trigger,
		bool	activate
	)

This function allows the user to enable or disable the PWM trigger. The PWM has 2 triggers. The trigger 0 is activated when the counter matches VAL 0, VAL 2, or VAL 4 register. The trigger 1 is activated when the counter matches VAL 1, VAL 3, or VAL 5.

Parameters

instance	Instance number of the PWM module.
subModule	The FlexPWM submodule that is configured
trigger	Trigger number that the user wants to activate
activate	Enable or disable the trigger

void PWM_DRV_SetTriggerVal	(	uint32_t	instance,
		pwm_module_t	subModule,
		pwm_val_regs_t	trigger,
		uint16_t	triggerVal
	)

This function sets the value in the compare register that generates a trigger. Note that the user must make sure that the value of the register being modified is not currently used to generate a PWM signal.

Parameters

instance	Instance number of the PWM module.
subModule	The FlexPWM submodule that is configured
trigger	Trigger number that we wish to configure
triggerVal	Trigger value

void PWM_DRV_SetupFault	(	uint32_t	instance,
		pwm_module_t	subModule,
		pwm_fault_input_t	faultNum,
		pwm_fault_setup_t *	faultParams,
		bool	pwmA,
		bool	pwmB,
		bool	pwmX
	)

This function configures a fault parameter and enables the fault for the appropriate sub-module signals.

Parameters

instance	Instance number of the PWM module.
subModule	The FlexPWM submodule that is configured
faultNum	Fault that should be configured
faultParams	Parameters that configure the fault
pwmA	true: PWM A is disabled by this fault; false: PWM A is not affected by this fault
pwmB	true: PWM B is disabled by this fault; false: PWM A is not affected by this fault
pwmX	true: PWM X is disabled by this fault; false: PWM A is not affected by this fault

void PWM_DRV_CounterStart	(	uint32_t	instance,
		uint8_t	value
	)

This function starts the PWM submodule counters.

Parameters

instance	Instance number of the PWM module.
value	Submodules to start; 4 bit value, 1-bit for each submodule

void PWM_DRV_CounterStop	(	uint32_t	instance,
		uint8_t	value
	)

This function stops the the PWM submodule counters.

Parameters

instance	Instance number of the PWM module.
value	Submodules to stop; 4 bit value, 1-bit for each submodule

void PWM_DRV_SetExternalClkFreq	(	uint32_t	instance,
		uint32_t	externalClkFreq
	)

When using an external signal as clock source, the user should provide the frequency of this clock source so that this driver can calculate the register values used to generate the requested PWM signal.

Parameters

instance	Instance number of the PWM module.
externalClkFreq	External clock frequency (in Hz).

Variable Documentation

PWM_Type* const g_pwmBase[PWM_INSTANCE_COUNT]

const IRQn_Type g_pwmCmpIrqId[FSL_FEATURE_PWM_CMP_INT_HANDLER_COUNT]

Overview

Initialization

Generate a PWM signal

Data Structures

Macros

Enumerations

Functions

Variables

Data Structure Documentation

Data Fields

Field Documentation

Enumeration Type Documentation

Function Documentation

Variable Documentation