writeLED

Turn LED on or off

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Syntax

writeLED(mypi,led,value)

Description

writeLED(mypi,led,value) overrides the default behavior of the LED and turns it on or off.

Note

To generate C/C++ code for this function, you must have an Embedded Coder® license.

example

Examples

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You can locate and control the on-board LED, turning it on and off.

Create a connection from the MATLAB® software to the Raspberry Pi® board.

mypi = raspi
mypi = 

  Raspi with Properties:

           DeviceAddress: 'raspberrypi-hysdu8X38o'
                    Port: 18725
               BoardName: 'Raspberry Pi Model B Rev 2'
           AvailableLEDs: {'led0'}
    AvailableDigitalPins: [4 14 15 17 18 22 23 24 25 27 30 31]
    AvailableSPIChannels: {}
      AvailableI2CBuses: {'i2c-0'  'i2c-1'}
             I2CBusSpeed: 100000

  Supported peripherals

The AvailableLEDs property shows the name of the user-controllable LED.

Show the location of the user-controllable LED on the board.

showLEDs(mypi)

LED on Raspberry Pi Board

Turn on the specified LED by setting its value to 1 or true.

writeLED(mypi,'led0',1)

Turn off the LED by setting its value to 0 or false.

writeLED(mypi,'led0',false)

Restarting the Raspberry Pi hardware returns the LED to its previous function as an activity indicator.

You can flash the LED in response to an input signal on one of the GPIO pins.

For example, you can use a button and a resistor in series to connect one of the +3.3 V outputs to GPIO 23. When you press the button, readDigitalPin reads the positive voltage, if buttonPressed becomes true, and the program flashes the LED 10 times.

for ii = 1:100
    buttonPressed = readDigitalPin(mypi, 23)
    if buttonPressed
        for jj = 1:10
            writeLED(mypi,'led0',1)
            pause(0.05)
            writeLED(mypi,'led0',0)
            pause(0.05)
        end
    end
    pause(0.1)
end

Input Arguments

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Connection to the Raspberry Pi hardware board, specified as a raspi object.

LED name, specified as a string.

To get the name and location of user-controllable LEDs, use showLEDs.

Example: 'led0'

Data Types: char

LED off or on, specified as a logical value.

Example: 0

Data Types: logical

Extended Capabilities

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Version History

Introduced in R2015b

See Also

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