尝试使用 Orange Pi Zero 上的 .Net Core 5 检测 GPIO 引脚的上升和下降。 引脚上升有时仅与引脚下降一起检测

Question

I am trying to detect a change in a GPIO pin of an Orange Pi Zero (basically the same as the Raspberry Pi). it is running Armbian Buster (ie Debian 10)

I created a simple.Net Core 5 console app, using.Net's builtin System.Device.Gpio library, to detect this:

public class GpioComms
{        
    GpioController _controller = new GpioController();

    public GpioComms()
    {
        _controller.OpenPin(10, PinMode.Input);
        _controller.RegisterCallbackForPinValueChangedEvent(10, PinEventTypes.Rising, onSignalPinRiseEvent);
        _controller.RegisterCallbackForPinValueChangedEvent(10, PinEventTypes.Falling, onSignalPinFallEvent);
    }

    private void onSignalPinRiseEvent(object sender, PinValueChangedEventArgs args)
    {
        Console.WriteLine(DateTime.Now + " " + args.PinNumber + " pin up");
    }

    private void onSignalPinFallEvent(object sender, PinValueChangedEventArgs args)
    {
        Console.WriteLine(DateTime.Now + " " + args.PinNumber + " pin down");
    }
}

I then wired a push button to GPIO pin 10 (physical pin 26 on the Orange Pi Zero) and ran the program. When I push the button in, about half the time it detects this immediately. When I release the push button, it always detects this immediately. But about half the time, it doesn't detect the pushing of the button, and only when I release the button, does the onSignalPinRiseEvent even fire (together with the onSignalPinFallEvent event)

In other words, about half the time, the pushing of the button (ie the rising of the GPIO pin) is only detected together with the releasing of the button (ie the falling of the GPIO pin), instead of being detected immediately when the button is pressed.

The strange thing is that I included a time stamp, and most of the time, even though I hold the button in for 3 seconds before releasing, the time stamp of the rising and falling are the same (but not always - there have been some rare occurrences where, even though both the rising and falling events only fired when I released the button, the timestamps displayed were 3 seconds apart).

I then tried registering only a single event handler for both rising and falling detection instead of two separate handlers:

_controller.RegisterCallbackForPinValueChangedEvent((int)Settings.GpioPin.Read, PinEventTypes.Rising | PinEventTypes.Falling, onSignalPinValueChangedEvent);

private void onSignalPinValueChangedEvent(object sender, PinValueChangedEventArgs args)
{
    Console.WriteLine(DateTime.Now + " - Pin " + args.PinNumber + " is "  + args.ChangeType);
}

But it made no difference.

This is a sample output - I was pushing the button in for about 3 seconds, then releasing for about 3 seconds:

2/20/2021 9:36:25 AM - Pin 10 is Rising
2/20/2021 9:36:25 AM - Pin 10 is Falling

2/20/2021 9:36:31 AM - Pin 10 is Rising
2/20/2021 9:36:31 AM - Pin 10 is Falling

2/20/2021 9:36:37 AM - Pin 10 is Rising
2/20/2021 9:36:37 AM - Pin 10 is Falling

2/20/2021 9:36:40 AM - Pin 10 is Rising
2/20/2021 9:36:43 AM - Pin 10 is Falling

2/20/2021 9:36:49 AM - Pin 10 is Rising
2/20/2021 9:36:49 AM - Pin 10 is Falling

2/20/2021 9:36:52 AM - Pin 10 is Rising
2/20/2021 9:36:55 AM - Pin 10 is Falling

2/20/2021 9:37:01 AM - Pin 10 is Rising
2/20/2021 9:37:01 AM - Pin 10 is Falling

2/20/2021 9:37:07 AM - Pin 10 is Rising
2/20/2021 9:37:07 AM - Pin 10 is Falling

2/20/2021 9:37:10 AM - Pin 10 is Rising
2/20/2021 9:37:13 AM - Pin 10 is Falling

2/20/2021 9:37:16 AM - Pin 10 is Rising
2/20/2021 9:37:18 AM - Pin 10 is Falling

2/20/2021 9:37:22 AM - Pin 10 is Rising
2/20/2021 9:37:24 AM - Pin 10 is Falling

2/20/2021 9:37:30 AM - Pin 10 is Rising
2/20/2021 9:37:30 AM - Pin 10 is Falling

In the above, the pairs that have the same timestamp are the problem ones. Those are the ones where nothing was written to the console when I pushed the button in, and then, three seconds later when I released the button, it wrote two lines (Rising and Falling) with the same timestamp at the same time.

Any ideas?

Answer 1

I would try to set the PinMode to "PinMode.InputPullUp", as i have had better success with that