Clear code the second time it runs

Question

1.25/5 (4 votes)

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Whit this part of my code I use to control the GPIO of a raspberry.
When I click on the start button and then the stop button the relay is working properly. When I do this for the second time i get an error. What am I doing wrong...

C#

{
   private const int relay1 = 4;
   private const int relay2 = 25;
   private const int relay3 = 22;
   private const int relay4 = 5;
   private GpioPin pin;
   private GpioPinValue pinValue;

   public MainPage()
   {
      //Scherm laden
      InitializeComponent();
   }

   //Relay1 START
   private void StartR1_Click(object sender, RoutedEventArgs e)
   {
      var gpio = GpioController.GetDefault();
      pin = gpio.OpenPin(relay1);
      pinValue = GpioPinValue.High;
      pin.Write(pinValue);
      pin.SetDriveMode(GpioPinDriveMode.Output);

      //Button Control Aan/Uit
      StartR1.IsEnabled = false;
      StopR1.IsEnabled = true;

   }

   //Relay1 STOP
   private void StopR1_Click(object sender, RoutedEventArgs e)
   {
      var gpio = GpioController.GetDefault();
      pinValue = GpioPinValue.Low;
      pin.Write(pinValue);
      pin.SetDriveMode(GpioPinDriveMode.Input);

      //Button Control Aan/Uit
      StartR1.IsEnabled = true;
      StopR1.IsEnabled = false;

   }

Posted 27-Oct-15 8:01am

MaikelO1

Updated 27-Oct-15 8:09am

phil.o

v2

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Comments

Patrice T 27-Oct-15 14:12pm

What error and where ?

Dave Kreskowiak 27-Oct-15 14:22pm

Why is it every newb thinks the error message is not an important piece of information when troubleshooting a problem?

ZurdoDev 27-Oct-15 14:25pm

The error is?

Zoltán Zörgő 27-Oct-15 14:26pm

As I see you are suing some GPIO class. Where is it from? Could you post a link to it?
On the other hand, you create those controllers without freeing them, I don't think it is wise to do so whatever class you are using.

Are using Windows 10? http://blogs.msdn.com/b/cdndevs/archive/2015/05/08/windows-10-how-to-use-iot-extension-for-raspberry-pi-2-part-1.aspx

3 solutions

Solution 2

Wild guess: the second time, the call to the openPin method fails because the pin is already open in exclusive mode (see the documentation[^]).
If that is the case then you should make such call just one time (possibly at your application startup).

Posted 27-Oct-15 8:31am

CPallini

Comments

Zoltán Zörgő 27-Oct-15 14:38pm

No wild guess, I have found the same.

Solution 3

Look here: https://ms-iot.github.io/content/en-US/win10/samples/PinMappingsRPi2.htm[^]

The pin opened is disposed[^] (wrapped in using clause).
You can't simply reopen it. Use the IDisposable pattern properly.

Posted 27-Oct-15 8:34am

Zoltán Zörgő

Comments

CPallini 27-Oct-15 16:35pm

5.

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bling · Accepted Answer · 2015-10-27T09:37:00

Solution 4

CPallini's and Zoltan's solutions are correct. More specifically, you need to do the following:

C#

var gpio = GpioController.GetDefault();
if (pin == null) // add this line.
    pin = gpio.OpenPin(relay1);

Good luck!

Posted 27-Oct-15 9:37am

bling

Comments

CPallini 27-Oct-15 16:35pm

5.