📰 NEWS

  • migrated to null-safety
  • SignalEvent's time property is no-longer that accurate, but instead two new properties, timestampNanos and timestamp are now provided which are super accurate. (This is because of changes in the kernel)
  • Raspberry Pi's main GPIO chip is no longer called pinctrl-bcm2835 on Pi 4's with latest kernel version. Instead its called pinctrl-bcm2711.

flutter_gpiod

A dart package for GPIO access on linux / Android (root required) using the linux GPIO character-device interface. Tested & working on ARM32 but should work on other 32-bit and 64-bit linux platforms as well.

Getting Started

Then, you can retrieve the list of GPIO chips attached to your system using FlutterGpiod.chips. Each chip has a name, label and a number of GPIO lines associated with it.

final chips = FlutterGpiod.instance.chips;

for (final chip in chips) {
    print("chip name: ${chip.name}, chip label: ${chip.label}");

    for (final line in chip.lines) {
        print("  line: $line");
    }
}

Each line also has some information associated with it that can be retrieved using GpioLine.info. The information can change at any time if the line is not owned/requested by you.

// Get the main Raspberry Pi GPIO chip.
// On Raspberry Pi 4 the main GPIO chip is called `pinctrl-bcm2711` and
// on older Pi's or a Pi 4 with older kernel version it's called `pinctrl-bcm2835`.
final chip = FlutterGpiod.instance.chips.singleWhere(
  (chip) => chip.label == 'pinctrl-bcm2711',
  orElse: () => FlutterGpiod.instance.chips.singleWhere((chip) => chip.label == 'pinctrl-bcm2835'),
);

// Get line 22 of the GPIO chip.
// This is the BCM 22 pin of the Raspberry Pi.
final line = chip.lines[22];

print("line info: ${line.info}")

To control a line (to read or write values or to listen for edges), you need to request it using GpioLine.requestInput or GpioLine.requestOutput.

final chip = FlutterGpiod.instance.chips.singleWhere((chip) => chip.label == 'pinctrl-bcm2835');
final line = chip.lines[22];

// request it as input.
line.requestInput();
print("line value: ${line.getValue()}");
line.release();

// now we're requesting it as output.
line.requestOutput(initialValue: true);
line.setValue(false);
line.release();

// request it as input again, but this time we're also listening
// for edges; both in this case.
line.requestInput(triggers: {SignalEdge.falling, SignalEdge.rising});

print("line value: ${line.getValue()}");

// line.onEvent will not emit any events if no triggers
// are requested for the line.
// this will run forever
await for (final event in line.onEvent) {
  print("got GPIO line signal event: $event");
}

line.release();

Libraries

flutter_gpiod