Overview

The SDK provides a driver for the Pulse Width Modulator (PWM).

The function PWM_Init() initializes the PWM module with specified configurations, the function PWM_GetDefaultConfig() could help to get the default configurations. The initialization function configures the module to use the specified clock for PWM operation.

The function PWM_SetupPwm() sets up the PWM channel for PWM output. The function can set up PWM signal property the channel. The PWM has 10 channels: 0 to 9. Each channel has its own period, compare match value, and polarity specified. The settings are applied to the specified channel requesting PWM output. The period and compare match are 16-bit values. At the compare match value, within the period, the PWM output toggles. The period value is loaded to downcounter, which decrements to 0. Once it reaches 0, it reloads the count and starts the signal out again, until the PWM channel is stopped. The function also sets up the channel output level after the channel is disabled. The 11th channel (ChannelAll) is a special channel which outputs the same output signals on other 10 channels (0 to 9) when it is set up and enabled.

The function PWM_ReadPeriodValue() reads the current period (downcounter value) for the PWM channel. The function PWM_ReadCompareValue() reads the compare match value for the PWM channel.

The function PWM_StartTimer() can be used to start the PWM channel. The function PWM_StopTimer() can be used to stop the PWM channel.

Provide functions to get and clear the PWM status.

Provide functions to enable/disable PWM interrupts and get current enabled interrupts.

Typical use case

PWM output

Configures PWM channel to output PWM signal.

int main(void)
{
    /* Structure of initialize PWM */
    pwm_config_t pwmConfig;
    pwm_setup_t pwmChan0;
    uint32_t pwmClockFrq;
    uint32_t pwmChan0Clk;
    /* Board pin, clock, debug console initialization */
    BOARD_InitHardware();
    PRINTF("PWM driver example\n");
    pwmClockFrq = CLOCK_GetFreq(kCLOCK_Pwm);
    PWM_GetDefaultConfig(&pwmConfig);
    /* Use 32MHz clock */
    pwmConfig.clk_sel = kPWM_Osc32Mclk;
    /* Initialize PWM */
    if (PWM_Init(BOARD_PWM_BASEADDR, &pwmConfig) != kStatus_Success)
    {
        PRINTF("PWM initialization failed\n");
        return 1;
    }
    /* Set up PWM channel 0 to generate PWM pulse of 100 us with 50% duty cycle */
    pwmChan0.pol_ctrl = kPWM_SetHighOnMatchLowOnPeriod;        
    pwmChan0.dis_out_level = kPWM_SetLow;
    pwmChan0.prescaler_val = 0;
    pwmChan0Clk = pwmClockFrq / (1 + pwmChan0.prescaler_val);
    pwmChan0.period_val = USEC_TO_COUNT(100, pwmChan0Clk);
    pwmChan0.comp_val = pwmChan0.period_val / 2;
    if(PWM_SetupPwm (BOARD_PWM_BASEADDR, kPWM_Pwm0, &pwmChan0) !=  kStatus_Success)
    {
        PRINTF("PWM chan0 setup failed\n");
        return 1;
    }
    /* Start the PWM generation channel 0 */
    PWM_StartTimer(BOARD_PWM_BASEADDR, kPWM_Pwm0);
    while (1U)
    {
        ;
    }
}

Files
file	fsl_pwm.h

Data Structures
struct	pwm_config_t
	PWM configuration structure. More...

struct	pwm_setup_t
	PWM channel setup structure. More...

Enumerations
enum	pwm_channels_t { kPWM_Pwm0 = 0x0, kPWM_Pwm1, kPWM_Pwm2, kPWM_Pwm3, kPWM_Pwm4, kPWM_Pwm5, kPWM_Pwm6, kPWM_Pwm7, kPWM_Pwm8, kPWM_Pwm9, kPWM_PwmAll }
	PWM channel selection values. More...

enum	pwm_polarity_control_t { kPWM_SetHighOnMatchLowOnPeriod = 0x0, kPWM_SetLowOnMatchHighOnPeriod }
	PWM channel polarity control values. More...

enum	pwm_dis_output_level_t { kPWM_SetLow = 0x0, kPWM_SetHigh }
	PWM channel disable output level values. More...

enum	pwm_interrupt_enable_t { kPWM_InterruptDisabled = 0x0, kPWM_InterruptEnabled }
	PWM channel interrupt enable flags. More...

enum	pwm_interrupt_status_t { kPWM_NoInterrupt = 0x0, kPWM_InterruptPendig }
	PWM channel interrupt status flags. More...

Driver version
#define	FSL_PWM_DRIVER_VERSION (MAKE_VERSION(2, 0, 0))
	PWM driver version 2.0.0. More...

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

status_t	PWM_Init (PWM_Type base, const pwm_config_t userConfig)
	Initializes the PWM module. More...

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

PWM module output
status_t	PWM_SetupPwm (PWM_Type base, pwm_channels_t pwm_chan, pwm_setup_t pwmSetup)
	Sets up the PWM channel. More...

PWM Interrupts Interface
static void	PWM_EnableInterrupts (PWM_Type *base, pwm_channels_t pwm_chan)
	Enable PWM channel interrupt. More...

static void	PWM_DisableInterrupts (PWM_Type *base, pwm_channels_t pwm_chan)
	Disable PWM channel interrupt. More...

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

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

void	PWM_ClearStatusFlags (PWM_Type *base, pwm_channels_t pwm_chan)
	Clears the PWM status flags. More...

Timer Start and Stop
static void	PWM_StartTimer (PWM_Type *base, pwm_channels_t pwm_chan)
	Start PWM channel. More...

static void	PWM_StopTimer (PWM_Type *base, pwm_channels_t pwm_chan)
	Stop PWM channel. More...

uint16_t	PWM_ReadPeriodValue (PWM_Type *base, pwm_channels_t pwm_chan)
	Read current period value for PWM channel. More...

uint16_t	PWM_ReadCompareValue (PWM_Type *base, pwm_channels_t pwm_chan)
	Read compare match value for PWM channel. More...

Data Structure Documentation

struct pwm_config_t

Data Fields
pwm_clock_source_t	clk_sel
	PWM clock select value.

struct pwm_setup_t

Data Fields
pwm_polarity_control_t	pol_ctrl
	Channel polarity control.

pwm_dis_output_level_t	dis_out_level
	Channel disable output level.

uint16_t	prescaler_val
	Channel Prescaler value. More...

uint16_t	period_val
	Channel PWM period value.

uint16_t	comp_val
	Channel compare match value.

Field Documentation

uint16_t pwm_setup_t::prescaler_val

10 bit value

Macro Definition Documentation

#define FSL_PWM_DRIVER_VERSION (MAKE_VERSION(2, 0, 0))

Enumeration Type Documentation

enum pwm_channels_t

Enumerator
kPWM_Pwm0	Channel 0.
kPWM_Pwm1	Channel 1.
kPWM_Pwm2	Channel 2.
kPWM_Pwm3	Channel 3.
kPWM_Pwm4	Channel 4.
kPWM_Pwm5	Channel 5.
kPWM_Pwm6	Channel 6.
kPWM_Pwm7	Channel 7.
kPWM_Pwm8	Channel 8.
kPWM_Pwm9	Channel 9.
kPWM_PwmAll	Channel 10 - All the channels will output same output programmed in this channel.

enum pwm_polarity_control_t

Enumerator
kPWM_SetHighOnMatchLowOnPeriod	Set high on compare match, set low at end of PWM period.
kPWM_SetLowOnMatchHighOnPeriod	Set low on compare match, set high at end of PWM period.

enum pwm_dis_output_level_t

Enumerator
kPWM_SetLow	Set to Low level.
kPWM_SetHigh	Set to High level.

enum pwm_interrupt_enable_t

Enumerator
kPWM_InterruptDisabled	PWM channel interrupt disabled.
kPWM_InterruptEnabled	PWM channel interrupt enabled.

enum pwm_interrupt_status_t

Enumerator
kPWM_NoInterrupt	PWM channel interrupt not occurred.
kPWM_InterruptPendig	PWM channel interrupt pending.

Function Documentation

void PWM_GetDefaultConfig ( pwm_config_t * userConfig )

The default values are:

* userConfig->clk_sel = kPWM_Osc32Mclk;

*

Parameters

userConfig Pointer to user's PWM config structure.

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

Call this API to ungate the PWM clock and configure the PWM HW.

Note: This API should be called at the beginning of the application to use the PWM driver, or any operation to the PWM module could cause hard fault because PWM module clock is not enabled. The configuration structure can be filled by user from scratch, or be set with default values by PWM_GetDefaultConfig(). After calling this API, the application can configure PWM channels to generate PWM outputs. Example:
* pwm_config_t userConfig = {

* .clk_sel = kPWM_Fro48Mclk,

* };

* PWM_Init(PWM, &userConfig);

*

Parameters

base	PWM base address
userConfig	pointer to user configuration structure

Returns: kStatus_Success - Success; kStatus_InvalidArgument - Invalid input parameter

void PWM_Deinit ( PWM_Type * base )

Parameters

base	PWM base address

status_t PWM_SetupPwm	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan,
		pwm_setup_t *	pwmSetup
	)

The function initializes the PWM channel according to the parameters passed in by the user. The function sets up the PWM compare match register & period registers.

Parameters

base	PWM base address
pwm_chan	PWM channel select value
pwmSetup	Pointer to PWM user setup structure

Returns: kStatus_Success - Success; kStatus_InvalidArgument - Invalid input parameter

static void PWM_EnableInterrupts	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan
	)

inlinestatic

This function enables the interrupt for the specified PWM channel.

Parameters

base	PWM base address
pwm_chan	PWM channel select value

static void PWM_DisableInterrupts	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan
	)

inlinestatic

This function disables the interrupt for the specified PWM channel.

Parameters

base	PWM base address
pwm_chan	PWM channel select value

static uint32_t PWM_GetEnabledInterrupts	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan
	)

inlinestatic

Parameters

base	PWM base address
pwm_chan	PWM channel select value

Returns: PWM interrupt enabled status. This is the one of the values specified in enumeration pwm_interrupt_enable_t

uint32_t PWM_GetStatusFlags	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan
	)

Parameters

base	PWM base address
pwm_chan	PWM channel select value

Returns: The status flags. This is the one of the value of members of the enumeration pwm_interrupt_status_t

void PWM_ClearStatusFlags	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan
	)

Parameters

base	PWM base address
pwm_chan	PWM channel select value

static void PWM_StartTimer	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan
	)

inlinestatic

The API will start PWM channel output on the pin. Before calling this API, make sure that the PWM channel is set up using PWM_SetupPwm() API.

Parameters

base	PWM base address
pwm_chan	PWM channel select value

static void PWM_StopTimer	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan
	)

inlinestatic

The API will stop PWM channel output on the pin.

Parameters

base	PWM base address
pwm_chan	PWM channel select value

uint16_t PWM_ReadPeriodValue	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan
	)

The API will read the current period value set for the PWM channel.

Parameters

base	PWM base address
pwm_chan	PWM channel select value

Returns: 16-bit period value

uint16_t PWM_ReadCompareValue	(	PWM_Type *	base,
		pwm_channels_t	pwm_chan
	)

The API will read the compare match value set for the PWM channel.

Parameters

base	PWM base address
pwm_chan	PWM channel select value

Returns: 16-bit period value

Overview

Typical use case

PWM output

Files

Data Structures

Enumerations

Driver version

Initialization and deinitialization

PWM module output

PWM Interrupts Interface

Status Interface

Timer Start and Stop

Data Structure Documentation

Data Fields

Data Fields

Field Documentation

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation