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

)

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 4 of file pwm.c.

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pwm_get_duty_cycle()

uint32_t pwm_get_duty_cycle

(

const int

pwm

)

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 8 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 7 of file pwm.c.

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pwm_get_steps()

uint32_t pwm_get_steps

(

const int

pwm

)

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 10 of file pwm.c.

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pwm_init()

void pwm_init	(	const int	pwm,
		const uint32_t	period
	)

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 3 of file pwm.c.

pwm_initialized()

bool pwm_initialized

(

const int

pwm

)

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 2 of file pwm.c.

pwm_set_duty_cycle()

void pwm_set_duty_cycle	(	const int	pwm,
		const uint32_t	duty
	)

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 5 of file pwm.c.

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pwm_set_period()

void pwm_set_period	(	const int	pwm,
		const uint32_t	period
	)

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 6 of file pwm.c.

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pwm_set_steps()

void pwm_set_steps	(	const int	pwm,
		const uint32_t	steps
	)

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 9 of file pwm.c.

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