Pwm Class Reference

Detailed Description

This file defines the PWM interface for libmraa

    mraa::Pwm* pwm;

    pwm = new mraa::Pwm(3);
    if (pwm == NULL) {
        return MRAA_ERROR_UNSPECIFIED;
    }
    fprintf(stdout, "Cycling PWM on IO3 (pwm3) \n");

    float value = 0.0f;
    while (running == 0) {
        value = value + 0.01f;
        pwm->write(value);
        usleep(50000);
        if (value >= 1.0f) {
            value = 0.0f;
        }
    }
    delete pwm;

Public Member Functions
	Pwm (int pin, int chipid=-1, bool owner=true)
	~Pwm ()
mraa_result_t	write (float percentage)
float	read ()
mraa_result_t	period (float period)
mraa_result_t	period_ms (int ms)
mraa_result_t	period_us (int us)
mraa_result_t	pulsewidth (float seconds)
mraa_result_t	pulsewidth_ms (int ms)
mraa_result_t	pulsewidth_us (int us)
mraa_result_t	enable (bool enable)
mraa_result_t	config_ms (int period, float duty)
mraa_result_t	config_percent (int period, float duty)

Constructor & Destructor Documentation

Pwm ( int  pin, int  chipid = -1, bool  owner = true  )

inline

instanciates a PWM object on a pin

Parameters

pin	the pin number used on your board
chipid	the pwmchip to use, use only in raw mode
owner	if you are the owner of the pin the destructor will unexport the pin from sysfs, default behaviour is you are the owner if the pinmapper exported it

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~Pwm ( )

inline

Pwm destructor

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Member Function Documentation

mraa_result_t write ( float  percentage )

inline

Set the output duty-cycle percentage, as a float

Parameters

percentage

A floating-point value representing percentage of output. The value should lie between 0.0f (representing on 0%) and 1.0f Values above or below this range will be set at either 0.0f or 1.0f

Returns

Result of operation

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float read ( )

inline

Read the ouput duty-cycle percentage, as a float

Returns

A floating-point value representing percentage of output. The value should lie between 0.0f (representing on 0%) and 1.0f Values above or below this range will be set at either 0.0f or 1.0f

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mraa_result_t period ( float  period )

inline

Set the PWM period as seconds represented in a float

Parameters

period

Period represented as a float in seconds

Returns

Result of operation

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mraa_result_t period_ms ( int  ms )

inline

Set period, milliseconds

Parameters

ms	milliseconds for period

Returns

Result of operation

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mraa_result_t period_us ( int  us )

inline

Set period, microseconds

Parameters

us	microseconds as period

Returns

Result of operation

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mraa_result_t pulsewidth ( float  seconds )

inline

Set pulsewidth, As represnted by seconds in a (float)

Parameters

seconds

The duration of a pulse

Returns

Result of operation

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mraa_result_t pulsewidth_ms ( int  ms )

inline

Set pulsewidth, milliseconds

Parameters

ms	milliseconds for pulsewidth

Returns

Result of operation

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mraa_result_t pulsewidth_us ( int  us )

inline

The pulsewidth, microseconds

Parameters

us	microseconds for pulsewidth

Returns

Result of operation

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mraa_result_t enable ( bool  enable )

inline

Set the enable status of the PWM pin. None zero will assume on with output being driven and 0 will disable the output

Parameters

enable

enable status of pin

Returns

Result of operation

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mraa_result_t config_ms ( int  period, float  duty  )

inline

Set the period and duty of a PWM object.

Parameters

period	represented in ms.
duty	represnted in ms as float.

Returns

Result of operation

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mraa_result_t config_percent ( int  period, float  duty  )

inline

Set the period and duty (percent) of a PWM object.

Parameters

period	as represented in ms.
duty	percentage i.e. 50% = 0.5f

Returns

Result of operation

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The documentation for this class was generated from the following file:

• /var/lib/jenkins/workspace/mraa-doc/api/mraa/pwm.hpp