PWM HAL

PWM Hardware Abstraction Layer API Reference. More...

Functions list
void	hal_pwm_configure_default (hal_pwm_config_t *config)
	Configure PWM configuration structure. More...
err_t	hal_pwm_open (handle_t *handle, bool hal_obj_open_state)
	Open the PWM HAL object on selected pin. More...
err_t	hal_pwm_set_freq (handle_t *handle, hal_pwm_config_t *config)
	Set PWM frequency in Hertz. More...
err_t	hal_pwm_start (handle_t *handle)
	Start PWM HAL context object. More...
err_t	hal_pwm_set_duty (handle_t *handle, float duty_ratio)
	Set PWM duty cycle in percentages. More...
err_t	hal_pwm_stop (handle_t *handle)
	Stop PWM module. More...
err_t	hal_pwm_close (handle_t *handle)
	Close PWM HAL object. More...

Detailed Description

API for configuring and manipulating PWM HAL module.

Function Documentation

hal_pwm_configure_default()

void hal_pwm_configure_default

(

hal_pwm_config_t *

config

)

Configures structure to default init values. Take into consideration that this is just structure variable initial values setting. Values need to be redefined by user.

Parameters

[in,out]

config

PWM HAL configuration settings. See hal_pwm_config_t structure definition for detailed explanation.

Default values:

Function	Default value
PWM pin	HAL_PIN_NC (invalid pin)
Frequency in Hz	0 (Frequency set to 0)

Returns

Nothing.

Example

hal_pwm_config_t hal_pwm_cfg;
 
hal_pwm_configure_default( &hal_pwm_cfg );

hal_pwm_open()

err_t hal_pwm_open	(	handle_t *	handle,
		bool	hal_obj_open_state
	)

Opens the PWM HAL object on selected pin. Allocates memory and pin for specified object.

Parameters

[in,out]	handle	PWM handle. See hal_pwm_t structure definition for detailed explanation.
[in]	hal_obj_open_state	PWM state, is it open or not.

Returns

The function can return one of the values defined by hal_pwm_err_t, which is size dependant on the architecture.

Warning

The following example describes how the function is used. Take into consideration that different hardware might not have the same pin. Make sure to accommodate pin name based on your hardware specifics.

Example

hal_pwm_t hal_pwm;
hal_pwm_config_t hal_pwm_cfg;
hal_pwm_configure_default( &hal_pwm_cfg );
hal_pwm_cfg.pin = PA1;
hal_pwm_cfg.freq_hz = 5000;
 
hal_pwm_open( &hal_pwm->handle, true );

hal_pwm_set_freq()

err_t hal_pwm_set_freq	(	handle_t *	handle,
		hal_pwm_config_t *	config
	)

This function is used to set the PWM frequency, it stops PWM module and sets duty cycle on 0. Take into consideration that the module will be re-initialized on the hardware level.

Parameters

[in]	handle	PWM handle. See hal_pwm_t structure definition for detailed explanation.
[in]	config	PWM configuration structure. See hal_pwm_config_t structure definition for detailed explanation.

Returns

The function can return one of the values defined by hal_pwm_err_t, which is size dependant on the architecture.

Precondition

Before calling this function, the user is expected to call hal_pwm_open

Postcondition

This function stops PWM module and sets duty cycle on 0.

Note

This function should be called first after hal_pwm_open for the PWM module to work. After calling this function, the user is expected to call hal_pwm_start and pwm_set_duty.

Example

hal_pwm_set_freq( &hal_pwm->handle, hal_pwm_cfg.freq_hz );

hal_pwm_start()

err_t hal_pwm_start

(

handle_t *

handle

)

Initializes PWM module on hardware level, if not already initialized and starts PWM module.

Parameters

[in]

handle

PWM handle.

Returns

The function can return one of the values defined by hal_pwm_err_t, which is size dependant on the architecture.

Precondition

Before calling this function, the user is expected to set frequency by using hal_pwm_set_freq function.

Example

hal_pwm_start( &hal_pwm->handle );

hal_pwm_set_duty()

err_t hal_pwm_set_duty	(	handle_t *	handle,
		float	duty_ratio
	)

Set PWM duty cycle in percentages. The user should enter the duty_ratio in percentages. The duty_ratio value should be between 0 and 1, (where 0 represents 0% and 1 represents 100%). If the user sets value for duty_ratio to be less than 0, duty_ratio is automatically set to 0(0%), and If the user sets value for duty_ratio to be greater than 1, duty_ratio is automatically set to 1(100%).

Parameters

[in]	handle	PWM handle.
[in]	duty_ratio	PWM duty_ratio.

Returns

The function can return one of the values defined by hal_pwm_err_t, which is size dependant on the architecture.

Precondition

This function should be called after the hal_pwm_start function for the PWM to work.

Example

hal_pwm_set_duty( &hal_pwm->handle, 0.5 );

hal_pwm_stop()

err_t hal_pwm_stop

(

handle_t *

handle

)

Disable output for specific PWM module.

Parameters

[in]

handle

PWM handle.

Returns

The function can return one of the values defined by hal_pwm_err_t, which is size dependant on the architecture.

Precondition

In order to stop PWM module user should first start PWM module. See hal_pwm_start function definition for detailed explanation.

Note

The PWM Module needs to be initialized so that the stop can be done.

Example

hal_pwm_stop( &hal_pwm->handle );

hal_pwm_close()

err_t hal_pwm_close

(

handle_t *

handle

)

De-allocates hardware resources for specific HAL object and de-initializes the module on a hardware level.

Parameters

[in,out]

handle

PWM handle.

Returns

Nothing.

Example

hal_pwm_close( &hal_pwm->handle );