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Dotnet Core WebApp没有GPIO访问权限

gpio raspbian asp.net-core c#

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Peter · 技术社区 · 7 年前

我正在尝试让一个aspnet核心web应用程序在我的树莓pi上运行。应用程序使用bifrost与覆盆子的gpio交互,但是每次我做 sudo dotnet run 它因错误而失败

Using launch settings from /home/pi/Desktop/keypad-alarm/keypad-alarm-server/Properties/launchSettings.json...     
Write value High to pin at /sys/class/gpio/gpio17/value

Unhandled Exception: System.UnauthorizedAccessException: Access to the path '/sys/class/gpio/gpio17/value' is denied. ---> System.IO.IOException: Operation not permitted    
--- End of inner exception stack trace ---    at 
System.IO.FileStream.WriteNative(ReadOnlySpan`1 source)    at 
System.IO.FileStream.FlushWriteBuffer()    at 
System.IO.FileStream.FlushInternalBuffer()    at 
System.IO.FileStream.Flush(Boolean flushToDisk)    at 
System.IO.FileStream.Flush()    at 
System.IO.StreamWriter.Flush(Boolean flushStream, Boolean flushEncoder)    at 
System.IO.StreamWriter.Dispose(Boolean disposing)  at 
System.IO.TextWriter.Dispose()   
 at System.IO.File.WriteAllText(String path, String contents)    at 
Bifrost.Devices.Gpio.GpioPin.Write(GpioPinValue pinValue)    at 
keypad_alarm_server.TweetController.Tweet(Int32 milliseconds) in 
/home/pi/Desktop/keypad-alarm/keypad-alarm-server/TweetController.cs:line 25    at 
keypad_alarm_server.Program.Main(String[] args) in /home/pi/Desktop/keypad-alarm/keypad-alarm-server/Program.cs:line 15

我应该提到的是,在我启动program.cs中的webserver之前,我会立即将gpio 17调高以发出哔哔声。

如何确保dotnet有足够的权限访问gpio?

1 回复 | 直到 7 年前

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Peter 7 年前

好吧,和往常一样,在你花时间发布问题之后,你会在某个地方找到答案…

未经授权的异常具有严重的误导性,因为缺少的是C中的以下声明: pin.SetDriveMode(GpioPinDriveMode.Output);

public class TweetController
{
    private static IGpioController _gpio = null;
    private const int PIN = 17;

    public TweetController()
    {
        _gpio = GpioController.Instance;
    }

    public void Tweet(int milliseconds){
        var pin = _gpio.OpenPin(PIN);
        pin.SetDriveMode(GpioPinDriveMode.Output); // open the gpio pin before writing or unauthorizedexception occurs
        pin.Write(GpioPinValue.High);
        Thread.Sleep(milliseconds);
        pin.Write(GpioPinValue.Low);
    }
}