Module for generating a pulse-width modulated output signal. More...

Modules
	PWM functionality configuration

Data Structures
struct	app_pwm_config_t
	PWM configuration structure used for initialization. More...

struct	app_pwm_t
	PWM instance structure. More...

Macros
#define	APP_PWM_NOPIN 0xFFFFFFFF

#define	APP_PWM_CHANNELS_PER_INSTANCE 2
	Number of channels for one timer instance (fixed to 2 due to timer properties).

#define	APP_PWM_INSTANCE (name, num)
	Macro for creating a PWM instance. More...

#define	APP_PWM_DEFAULT_CONFIG_1CH (period_in_us, pin)
	PWM instance default configuration (1 channel). More...

#define	APP_PWM_DEFAULT_CONFIG_2CH (period_in_us, pin0, pin1)
	PWM instance default configuration (2 channels). More...

Typedefs
typedef uint16_t	app_pwm_duty_t

typedef void(*	app_pwm_callback_t )(uint32_t)
	PWM callback that is executed when a PWM duty change has been completed. More...

Enumerations
enum	app_pwm_polarity_t { APP_PWM_POLARITY_ACTIVE_LOW = 0, APP_PWM_POLARITY_ACTIVE_HIGH = 1 }
	Channel polarity.

Functions
bool	app_pwm_busy_check ( app_pwm_t const *const p_instance)
	Function for checking if the PWM instance is busy updating the duty cycle. More...

ret_code_t	app_pwm_init ( app_pwm_t const const p_instance, app_pwm_config_t const const p_config, app_pwm_callback_t p_ready_callback)
	Function for initializing a PWM instance. More...

ret_code_t	app_pwm_uninit ( app_pwm_t const *const p_instance)
	Function for uninitializing a PWM instance and releasing the allocated resources. More...

void	app_pwm_enable ( app_pwm_t const *const p_instance)
	Function for enabling a PWM instance after initialization. More...

void	app_pwm_disable ( app_pwm_t const *const p_instance)
	Function for disabling a PWM instance after initialization. More...

ret_code_t	app_pwm_channel_duty_set ( app_pwm_t const *const p_instance, uint8_t channel, app_pwm_duty_t duty)
	Function for setting the PWM channel duty cycle in percents. More...

app_pwm_duty_t	app_pwm_channel_duty_get ( app_pwm_t const *const p_instance, uint8_t channel)
	Function for retrieving the PWM channel duty cycle in percents. More...

Functions accessing values in ticks
Auxiliary functions that allow to get values in actual timer ticks.
ret_code_t	app_pwm_channel_duty_ticks_set ( app_pwm_t const *const p_instance, uint8_t channel, uint16_t ticks)
	Function for setting PWM channel duty cycle in clock ticks. More...

uint16_t	app_pwm_channel_duty_ticks_get ( app_pwm_t const *const p_instance, uint8_t channel)
	Function for retrieving the PWM channel duty cycle in ticks. More...

uint16_t	app_pwm_cycle_ticks_get ( app_pwm_t const *const p_instance)
	Function for returning the number of ticks in a whole cycle. More...

Detailed Description

Module for generating a pulse-width modulated output signal.

This module provides a PWM implementation using timers, GPIOTE, and PPI.

Resource usage:

2 PPI channels per instance + 2 PPI channels per PWM channel.
1 PPI group per instance.
1 GPIOTE channel per PWM channel.

For example, a PWM instance with two channels will consume 2 + 4 PPI channels, 1 PPI group, and 2 GPIOTE channels.

The maximum number of PWM channels per instance is 2.

Macro Definition Documentation

#define APP_PWM_DEFAULT_CONFIG_1CH	(	period_in_us,
		pin
	)

Value:

         {                                                                                  \
        
         .pins            = {pin, APP_PWM_NOPIN},                                       \
        
         .pin_polarity    = {APP_PWM_POLARITY_ACTIVE_LOW, APP_PWM_POLARITY_ACTIVE_LOW}, \
        
         .num_of_channels = 1,                                                          \
        
         .period_us       = period_in_us                                                \
        
         }

PWM instance default configuration (1 channel).

#define APP_PWM_DEFAULT_CONFIG_2CH	(	period_in_us,
		pin0,
		pin1
	)

Value:

         {                                                                                  \
        
         .pins            = {pin0, pin1},                                               \
        
         .pin_polarity    = {APP_PWM_POLARITY_ACTIVE_LOW, APP_PWM_POLARITY_ACTIVE_LOW}, \
        
         .num_of_channels = 2,                                                          \
        
         .period_us       = period_in_us                                                \
        
         }

PWM instance default configuration (2 channels).

#define APP_PWM_INSTANCE	(	name,
		num
	)

Value:

         
          const
         
          nrf_drv_timer_t
         
         m_pwm_##name##_timer =
         
          NRF_DRV_TIMER_INSTANCE
         
         (num); \
        
         app_pwm_cb_t m_pwm_##name##_cb;                                           \
        
          /*lint -e{545}*/
         
         \
        
         const
         
          app_pwm_t
         
         name = {                                                  \
        
         .
         
          p_cb
         
         = &m_pwm_##name##_cb,                                        \
        
         .p_timer = &m_pwm_##name##_timer,                                     \
        
         }

Macro for creating a PWM instance.

Typedef Documentation

typedef void(* app_pwm_callback_t)(uint32_t)

PWM callback that is executed when a PWM duty change has been completed.

Parameters

[in] pwm_id PWM instance ID.

Function Documentation

bool app_pwm_busy_check ( app_pwm_t const *const p_instance )

Function for checking if the PWM instance is busy updating the duty cycle.

Parameters

[in] p_instance PWM instance.

Return values

True	If the PWM instance is ready for duty cycle changes.
False	If a change operation is in progress.

app_pwm_duty_t app_pwm_channel_duty_get	(	app_pwm_t const *const	p_instance ,
		uint8_t	channel
	)

Function for retrieving the PWM channel duty cycle in percents.

Parameters

[in]	p_instance	PWM instance.
[in]	channel	Channel number.

Returns: Duty cycle value.

ret_code_t app_pwm_channel_duty_set	(	app_pwm_t const *const	p_instance ,
		uint8_t	channel ,
		app_pwm_duty_t	duty
	)

Function for setting the PWM channel duty cycle in percents.

A duty cycle change requires one full PWM clock period to finish. If another change is attempted for any channel of given instance before the current change is complete, the new attempt will result in the error NRF_ERROR_BUSY.

Parameters

[in]	p_instance	PWM instance.
[in]	channel	Channel number.
[in]	duty	Duty cycle (0 - 100).

Return values

NRF_SUCCESS	If the operation was successful.
NRF_ERROR_BUSY	If the PWM is not ready yet.
NRF_ERROR_INVALID_STATE	If the given instance was not initialized.

uint16_t app_pwm_channel_duty_ticks_get	(	app_pwm_t const *const	p_instance ,
		uint8_t	channel
	)

Function for retrieving the PWM channel duty cycle in ticks.

This function retrieves the real, currently set duty cycle in ticks. For one full PWM cycle the value might be different than the value set by the last app_pwm_channel_duty_ticks_set function call.

Parameters

[in]	p_instance	PWM instance.
[in]	channel	Channel number.

Returns: Number of ticks set for selected channel.

ret_code_t app_pwm_channel_duty_ticks_set	(	app_pwm_t const *const	p_instance ,
		uint8_t	channel ,
		uint16_t	ticks
	)

Function for setting PWM channel duty cycle in clock ticks.

Note: Duty cycle changes require one full PWM clock period to finish. Until that, the next change attempt (for any channel of given instance) will result in an NRF_ERROR_BUSY error.

Parameters

[in]	p_instance	PWM instance.
[in]	channel	Channel number.
[in]	ticks	Number of PWM clock ticks.

Return values

NRF_SUCCESS	If the operation was successful.
NRF_ERROR_BUSY	If PWM is not ready yet.
NRF_ERROR_INVALID_STATE	If the given instance was not initialized.

uint16_t app_pwm_cycle_ticks_get ( app_pwm_t const *const p_instance )

Function for returning the number of ticks in a whole cycle.

Parameters

[in] p_instance PWM instance.

Returns: Number of ticks that corresponds to 100% of the duty cycle.

void app_pwm_disable ( app_pwm_t const *const p_instance )

Function for disabling a PWM instance after initialization.

Parameters

[in] p_instance PWM instance.

void app_pwm_enable ( app_pwm_t const *const p_instance )

Function for enabling a PWM instance after initialization.

Parameters

[in] p_instance PWM instance.

ret_code_t app_pwm_init	(	app_pwm_t const *const	p_instance ,
		app_pwm_config_t const *const	p_config ,
		app_pwm_callback_t	p_ready_callback
	)

Function for initializing a PWM instance.

Parameters

[in]	p_instance	PWM instance.
[in]	p_config	Initial configuration.
[in]	p_ready_callback	Pointer to ready callback function (or NULL to disable).

Return values

NRF_SUCCESS	If initialization was successful.
NRF_ERROR_NO_MEM	If there were not enough free resources.
NRF_ERROR_INVALID_PARAM	If an invalid configuration structure was passed.
NRF_ERROR_INVALID_STATE	If the timer/PWM is already in use or if initialization failed.

ret_code_t app_pwm_uninit ( app_pwm_t const *const p_instance )

Function for uninitializing a PWM instance and releasing the allocated resources.

Parameters

[in] p_instance PWM instance.

Return values

NRF_SUCCESS	If uninitialization was successful.
NRF_ERROR_INVALID_STATE	If the given instance was not initialized.

Pulse-width modulation (PWM)

nRF5 SDK v12.1.0

Modules

Data Structures

Macros

Typedefs

Enumerations

Functions

Functions accessing values in ticks

Detailed Description

Macro Definition Documentation

Typedef Documentation

Function Documentation