PWM library

Enumerations
enum	pwm_index_t {   PWM0 , PWM1 , PWM2 , PWM3 ,   PWM4 , PWM5 , NUM_PWMS }

Functions
bool	pwm_initialized (const int pwm)
void	pwm_init (const int pwm, const uint32_t period)
void	pwm_destroy (const int pwm)
void	pwm_set_duty_cycle (const int pwm, const uint32_t duty)
void	pwm_set_period (const int pwm, const uint32_t period)
uint32_t	pwm_get_period (const int pwm)
uint32_t	pwm_get_duty_cycle (const int pwm)
void	pwm_set_steps (const int pwm, const uint32_t steps)
uint32_t	pwm_get_steps (const int pwm)

Detailed Description

Functions to use Pulse Width Modulation (PWM).

Each of the 6 PWM channels (numbered 0..NUM_PWMS-1) can be linked to any mappable pin (e.g. green or color LEDs, buttons).

PWM can also be used through GPIO (see gpio.h and pinmap.h). Note that GPIO numbering (SWB_PWM0..SWB_PWM5) is then used instead of 0..NUM_PWMS-1 (PWM0..PWM5).

Enumeration Type Documentation

pwm_index_t

enum pwm_index_t

Enum of PWM channels.

All functions use a PWM channel from 0..NUM_PWMS-1. Alternatively, you can use PWMi instead of just i if you find that clearer.

Enumerator
PWM0
PWM1
PWM2
PWM3
PWM4
PWM5
NUM_PWMS

Definition at line 47 of file pwm.h.

Function Documentation

pwm_destroy()

void pwm_destroy ( const int  pwm )

extern

Removes the instantiated shared memory system of the PWM channel.

Parameters

pwm	The PWM channel to destroy.

Warning

Fails with program exit if pwm is outside valid range.

Definition at line 72 of file pwm.c.

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pwm_get_duty_cycle()

uint32_t pwm_get_duty_cycle ( const int  pwm )

extern

Gets the duty cycle of the specified PWM channel.

Parameters

pwm	The PWM channel.

Returns

The duty cycle of the specified PWM channel.

Warning

Fails with program exit if pwm is outside valid range or if pwm has not been initialized.

Definition at line 78 of file pwm.c.

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pwm_get_period()

uint32_t pwm_get_period

(

const int

pwm

)

Returns the period of a certain PWM channel.

Parameters

pwm	The PWM channel.

Returns

The period of the specified PWM channel as an uint32_t.

Warning

Fails with program exit if pwm is outside valid range or if pwm has not been initialized.

Definition at line 83 of file pwm.c.

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pwm_get_steps()

uint32_t pwm_get_steps ( const int  pwm )

extern

Get the number of steps a certain channel has taken so far.

Parameters

pwm	PWM channel.

Returns

The number of steps that have been taken; 0 is off and -1 is continous.

Warning

Fails with program exit if pwm is outside valid range or if pwm has not been initialized.

Definition at line 98 of file pwm.c.

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pwm_init()

void pwm_init ( const int  pwm, const uint32_t  period  )

extern

Initializes the PWM channel with the specified period.

Parameters

pwm	the PWM channel to initialize.
period	The period to set for the PWM channel.

Warning

Fails with program exit if pwm is outside valid range.

Definition at line 61 of file pwm.c.

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pwm_initialized()

bool pwm_initialized ( const int  pwm )

extern

Checks if the channel index is initialized.

Parameters

pwm	The PWM channel

Returns

True if initialized, false if not

Warning

Fails with program exit if pwm is outside valid range.

Definition at line 38 of file pwm.c.

pwm_set_duty_cycle()

void pwm_set_duty_cycle ( const int  pwm, const uint32_t  duty  )

extern

Sets the duty cycle for the specified PWM channel.

Parameters

pwm	The PWM channel.
duty	The duty cycle to set for the PWM channel.

Warning

Fails with program exit if pwm is outside valid range or if pwm has not been initialized.

Definition at line 93 of file pwm.c.

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pwm_set_period()

void pwm_set_period ( const int  pwm, const uint32_t  period  )

extern

Sets the period for the specified PWM channel.

Parameters

pwm	The PWM channel.
period	The period to set for the PWM channel.

Warning

Fails with program exit if pwm is outside valid range or if pwm has not been initialized.

Definition at line 88 of file pwm.c.

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pwm_set_steps()

void pwm_set_steps ( const int  pwm, const uint32_t  steps  )

extern

Generates steps steps on the PWM channel.

Parameters

pwm	The PWM channel.
steps	The number of steps to cycle, 0 to turn off and -1 to run continously.

Warning

Fails with program exit if pwm is outside valid range or if pwm has not been initialized.

Definition at line 103 of file pwm.c.

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