rpigpio

rpigpio

Package for controlling GPIOs on the Raspberry Pi using plain GO.

About

This package provides access to the GPIO pins on any Raspberry Pi. The GPIOs are switch and controlled by directly writing to the corresponding registers.

The used Raspberry Pi hardware is automatically detected to accommodate different hardware addresses. For this to work, a curated list is included via the package github.com/DerLukas15/rpihardware.

Installation

go get github.com/DerLukas15/rpigpio

Usage

First initialize the package. This will determine the hardware. (You can also define your pins and initialize later. However the initialization has to be done before any methods are called.)

err := rpigpio.Initialize()

Now create the pin object. Use the GPIO numbers which you can find online and not the physical pin number.

pin, err := rpigpio.NewPin(17)

Typical uses

Output

Set the 'direction' of the pin:

err := pin.Mode(rpigpio.ModeOutput)

Set the output high:

err := pin.Set(1)

Set the output low:

err := pin.Set(0)

If the direction of the pin is an input, the Set method won't do anything.

Input

Set the 'direction' of the pin:

err := pin.Mode(rpigpio.ModeInput)

Get the current value: Now set the 'direction' of the pin:

value, err := pin.Get()

If the direction of the pin is an output, the 'Get' method will always return 0.

Extended uses

Alternate modes

To activate alternate modes for a pin use (e.g. for alternate mode 1)

err := pin.Mode(rpigpio.ModeAlternate1)

Pull-Up / Pull-Down

To activate the build in Pull-Up or Pull-Down resistors use:

For Pull-Up

err := pin.Pull(rpigpio.PullUp)

For Pull-Down

err := pin.Pull(rpigpio.PullDown)

To disable Pull-Up or Pull-Down

err := pin.Pull(rpigpio.PullOff)

The current status of the Pull-Up / Pull-Down resistors can not be read due to hardware restrictions.

Event Detects

There are different detect methods for events described below. To get the result of any event use:

hasEvent, err := pin.Event()

Reading an event will clear the event to be ready for the next one. To prevent the automatic event clearing set

rpigpio.NoEventClearing = true

Don't forget to clear the events by yourself

err := pin.ClearEvent()

If an event is still valid during an attempt to clear it, the clear won't do anything.

Enable rising edge detection with

err := pin.RisingEdgeDetect(true)

Any transition from 0 -> 1 will trigger the event.

Can be used together with 'Falling Edge Detect'

An asynchronous version of this method is available. This will sample outside of the system clock making it perfect for use with very short edges. Use pin.ARisingEdgeDetect(true)

Enable rising edge detection with

err := pin.FallingEdgeDetect(true)

Any transition from 1 -> 0 will trigger the event.

Can be used together with 'Rising Edge Detect'

An asynchronous version of this method is available. This will sample outside of the system clock making it perfect for use with very short edges. Use pin.FallingEdgeDetect(true)

Will set the event once the pin is high:

err := pin.HighDetect(true)

Will set the event once the pin is low:

err := pin.LowDetect(true)

License

MIT, see LICENSE