📰 NEWS

  • If you have root access, works on Android too (See issue #9)
  • even though the name seems to imply otherwise, the flutter SDK is not required to use this package.
  • libgpiod is no longer required
  • a lot of the async stuff has gone away, making it nicer & easier to use
  • The package uses FFI with ioctls now, which should result in lower latency. (The event listener isolate gets signal edge events ~300us after they ocurred, the main isolate after ~1000us)
  • works without flutter-pi now too
  • tested & working on ARM32, but should work on other 32-bit and 64-bit linux platforms too (untested though)

flutter_gpiod

A dart package for GPIO access on linux / Android (root required) using the linux GPIO character-device interface.

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 chip with label 'pinctrl-bcm2835'.
// This is the main Raspberry Pi GPIO chip.
final chip = FlutterGpiod.instance.chips.singleWhere((chip) => chip.label == 'pinctrl-bcm2835');

// Get line 22 of the 'pinctrl-bcm2835' 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