Gpio Class Reference

Detailed Description

This file defines the gpio interface for libmraa

    /* initialize GPIO pin */
    mraa::Gpio gpio_1(GPIO_PIN_1);

    /* initialize GPIO pin */
    mraa::Gpio gpio_2(GPIO_PIN_2);

    /* set GPIO to output */
    status = gpio_1.dir(mraa::DIR_OUT);
    if (status != mraa::SUCCESS) {
        printError(status);
        return EXIT_FAILURE;
    }

    /* set gpio 24 to output */
    status = gpio_2.dir(mraa::DIR_OUT);
    if (status != mraa::SUCCESS) {
        printError(status);
        return EXIT_FAILURE;
    }

    /* toggle both GPIO's */
    while (flag) {
        status = gpio_1.write(1);
        if (status != mraa::SUCCESS) {
            printError(status);
            return EXIT_FAILURE;
        }
        status = gpio_2.write(0);
        if (status != mraa::SUCCESS) {
            printError(status);
            return EXIT_FAILURE;
        }

        sleep(1);

        status = gpio_1.write(0);
        if (status != mraa::SUCCESS) {
            printError(status);
            return EXIT_FAILURE;
        }

        status = gpio_2.write(1);
        if (status != mraa::SUCCESS) {
            printError(status);
            return EXIT_FAILURE;
        }

        sleep(1);
    }

Public Member Functions
	Gpio (int pin, bool owner=true, bool raw=false)
	Gpio (void *gpio_context)
	~Gpio ()
Result	edge (Edge mode)
Result	isr (Edge mode, void(*fptr)(void *), void *args)
Result	isrExit ()
Result	mode (Mode mode)
Result	dir (Dir dir)
Dir	readDir ()
int	read ()
Result	write (int value)
Result	useMmap (bool enable)
int	getPin (bool raw=false)
Result	inputMode (InputMode mode)
Result	outputMode (OutputMode mode)

Constructor & Destructor Documentation

Gpio ( int  pin, bool  owner = true, bool  raw = false  )

inline

Instantiates a Gpio object

Parameters

pin	pin number to use
owner	(optional) Set pin owner, default behaviour is to 'own' the pin if we exported it. This means we will close it on destruct. Otherwise it will get left open. This is only valid in sysfs use cases
raw	(optional) Raw pins will use gpiolibs pin numbering from the kernel module. Note that you will not get any muxers set up for you so this may not always work as expected.

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Gpio ( void *  gpio_context )

inline

Gpio Constructor, takes a pointer to the GPIO context and initialises the GPIO class

Parameters

gpio_context

void * to GPIO context

~Gpio ( )

inline

Gpio object destructor, this will only unexport the gpio if we where the owner

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Member Function Documentation

Result edge ( Edge  mode )

inline

Set the edge mode for ISR

Parameters

mode	The edge mode to set

Returns

Result of operation

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Result isr ( Edge  mode, void(*)(void *)  fptr, void *  args  )

inline

Sets a callback to be called when pin value changes

Parameters

mode	The edge mode to set
fptr	Function pointer to function to be called when interrupt is triggered
args	Arguments passed to the interrupt handler (fptr)

Returns

Result of operation

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Result isrExit ( )

inline

Exits callback - this call will not kill the isr thread immediately but only when it is out of it's critical section

Returns

Result of operation

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Result mode ( Mode  mode )

inline

Change Gpio mode

Parameters

mode	The mode to change the gpio into

Returns

Result of operation

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Result dir ( Dir  dir )

inline

Change Gpio direction

Parameters

dir	The direction to change the gpio into

Returns

Result of operation

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Dir readDir ( )

inline

Read Gpio direction

Exceptions

std::runtime_error

in case of failure

Returns

Result of operation

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int read ( )

inline

Read value from Gpio

Returns

Gpio value

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Result write ( int  value )

inline

Write value to Gpio

Parameters

value

Value to write to Gpio

Returns

Result of operation

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Result useMmap ( bool  enable )

inline

Enable use of mmap i/o if available.

Parameters

enable

true to use mmap

Returns

Result of operation

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int getPin ( bool  raw = false )

inline

Get pin number of Gpio. If raw param is True will return the number as used within sysfs. Invalid will return -1.

Parameters

raw	(optional) get the raw gpio number.

Returns

Pin number

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Result inputMode ( InputMode  mode )

inline

Change Gpio input mode

Parameters

mode	The mode to change the gpio input

Returns

Result of operation

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Result outputMode ( OutputMode  mode )

inline

Change Gpio output driver mode

Parameters

mode	Set output driver mode

Returns

Result of operation

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

• api/mraa/gpio.hpp