WOLFRAM LANGUAGE DEVICE CONNECTION

GPIO (General Purpose I/O)

This feature is not supported on the Wolfram Cloud.

provides low-level general-purpose input and output through digital pins directly connected to the processor running the Wolfram Language.

Note: By default,

allows any pin to be used interchangeably in read and write mode. DeviceConfigure can be used to configure specific pins as read or write.

Note: To access GPIO you must be logged in as root or be running the Wolfram Language as root.

The possible values of GPIO pins are taken to be 0 and 1, corresponding to "low" and "high".
allows pins to be specified by integers.
On a Raspberry Pi, the following pins are available for reading and writing: 4, 7, 8, 9, 10, 11, 14, 15, 17, 18, 22, 23, 24, 25, 28, 29, 30, 31.
On the Raspberry Pi, pins can also be referenced using the WiringPi numbering scheme by specifying them in the form .

FindDevices["GPIO"] gives a GPIO DeviceObject if GPIO is available on your computer system.

If GPIO is present, it is always accessible and does not require a connection step.
DeviceOpen["GPIO"] is not required, but can be used to obtain a DeviceObject whose properties can be queried.

Configuration is not required for GPIO. Without configuration, any pin will automatically switch between input and output on read and write. Note that if a pin is used in a direction that is not intended, this may damage your system.

DeviceConfigure["GPIO",n->dir]
sets the direction of pin n to be dir.

DeviceConfigure["GPIO",{n₁->dir₁,n₂->dir₂,…}]
sets direction for pin .

Possible directions are: , , and None.
Setting the direction to None releases a pin if it has previously been configured.
DeviceConfigure ignores requests to configure any pin that is being accessed by an asynchronous task.
If an attempt is made to use a GPIO pin in a direction inconsistent with its configuration, an error will be generated.

DeviceRead["GPIO",p]
gives the value of GPIO pin p.

DeviceRead["GPIO",{p₁,p₂,…}]
gives a list of the values of GPIO pins .

The value of a GPIO pin is always either 0 or 1.
Note: By default, allows any pin to be used interchangeably in read and write mode. DeviceConfigure can be used to configure specific pins as read or write.

Note: To access GPIO you must be logged in as root or be running the Wolfram Language as root.

DeviceWrite["GPIO",p->v]
writes the value v to GPIO pin p.

The value v must be either 0 or 1.
Note: By default, allows any pin to be used interchangeably in read and write mode. DeviceConfigure can be used to configure specific pins as read or write.

DeviceClose["GPIO"] is not required, but can effectively be used to reset all pins to their default state and marks the corresponding DeviceObject as closed.