pwm.c File Reference

PWM general purpose interface code for file system. More...

#include <stdio.h>
#include "bbbandroidHAL.h"

Macros
#define	SYSFS_PWM_DIR   "/sys/class/pwm"

Functions
int	pwmSetPeriod (const uint8_t channel, const uint32_t period_ns)
int	pwmGetPeriod (const uint8_t channel)
int	pwmSetDutyCycle (const uint8_t channel, const uint32_t duration_ns)
int	pwmGetDutyCycle (const uint8_t channel)
int	pwmSetPolarity (const uint8_t channel, const uint8_t polarity)
int	pwmGetPolarity (const uint8_t channel)
int	pwmRun (const uint8_t channel)
int	pwmStop (const uint8_t channel)
int	pwmRunCheck (const uint8_t channel)

Variables
static char	fsBuf [100]

Detailed Description

PWM general purpose interface code for file system.

Author

Ankur Yadav (ankur.nosp@m.ayad.nosp@m.av@gm.nosp@m.ail..nosp@m.com)

Macro Definition Documentation

#define SYSFS_PWM_DIR   "/sys/class/pwm"

File system path to access PWM

Function Documentation

int pwmGetDutyCycle

(

const uint8_t

channel

)

It takes channel number as input and returns the value of duty cycle of specified channel in nano seconds.

Parameters

channel

a constant uint8_t argument.

Returns

value of duty cycle on success and -1 if it fails.

int pwmGetPeriod

(

const uint8_t

channel

)

It takes channel number as input and returns the value of period of specified channel in nano seconds.

Parameters

channel

a constant uint8_t argument.

Returns

value of period on success and -1 if it fails.

int pwmGetPolarity

(

const uint8_t

channel

)

It takes channel number as input and returns the value of polarity of specified channel.

Parameters

channel

a constant uint8_t argument.

Returns

value of polarity on success and -1 if it fails.

int pwmRun

(

const uint8_t

channel

)

It takes channel number as input and sets run for that channel so that pwm starts running for that channel.

Parameters

channel

a constant uint8_t argument.

Returns

0 on success and -1 if it fails.

int pwmRunCheck

(

const uint8_t

channel

)

It takes channel number as input and returns the value of run for that channel.

Parameters

channel

a constant uint8_t argument.

Returns

value of run on success and -1 if it fails.

int pwmSetDutyCycle	(	const uint8_t	channel,
		const uint32_t	duration_ns
	)

It takes channel and duty cycle to be assigned in nano seconds and sets duty cycle of that channel to specified value using file system.

Parameters

channel	a constant uint8_t argument.
duration_ns	a constant uint32_t argument.

Returns

0 on success and -1 if it fails.

int pwmSetPeriod	(	const uint8_t	channel,
		const uint32_t	period_ns
	)

It takes channel and period to be assigned in nano seconds and sets period of that channel to specified value using file system.

Parameters

channel	a constant uint8_t argument.
period_ns	a constant uint32_t argument.

Returns

0 on success and -1 if it fails.

int pwmSetPolarity	(	const uint8_t	channel,
		const uint8_t	polarity
	)

It takes channel and polarity to be assigned and sets polarity of that channel to the specified value using file system.

Parameters

channel	a constant uint8_t argument.
polarity	a constant uint8_t argument.

Returns

0 on success and -1 if it fails.

int pwmStop

(

const uint8_t

channel

)

It takes channel number as input and sets run to 0 for that channel so that pwm stops for that channel.

Parameters

channel

a constant uint8_t argument.

Returns

0 on success and -1 if it fails.

Variable Documentation

char fsBuf[100]

static

Buffer to store generated file system path using snprintf