6 replies to this topic

[ncsteinb]

Hello, this is my first post on here. I have been tooling around with my new Netduino Plus for a few weeks now and I've been wanting to be able to do multiple things at once, such as controlling two motor speeds and directions. I have done a little digging and have come to find that what I am trying to do it called Multi-Threading. So, to learn, I started with a fairly simple process. I have created a three LED marquee, and a fourth LED that turns on when I press a button. The problem is that I keep getting an error in the debug saying I have unreachable code. Can anyone help me fix this issue? Here is my code:

using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using SecretLabs.NETMF.Hardware;
using SecretLabs.NETMF.Hardware.NetduinoPlus;

namespace NetduinoPlusApplication1
{
    public class Program
    {
        static void Main()
        {
            Thread t = new Thread(RedCheck);
            t.Start();

            OutputPort bLED = new OutputPort(Pins.GPIO_PIN_D5,false);
            OutputPort gLED = new OutputPort(Pins.GPIO_PIN_D6,false);
            OutputPort rLED = new OutputPort(Pins.GPIO_PIN_D9,false);
            AnalogInput Pot = new AnalogInput(Pins.GPIO_PIN_A0);
            AnalogInput PV = new AnalogInput(Pins.GPIO_PIN_A1);

            Pot.SetRange(5, 500);
            int PotValue = 0;

            while(true)
            {
                PotValue = Pot.Read();
                gLED.Write(true);
                Thread.Sleep(PotValue);
                gLED.Write(false);
                
                PotValue = Pot.Read();
                bLED.Write(true);
                Thread.Sleep(PotValue);
                bLED.Write(false);
                
                PotValue = Pot.Read();
                rLED.Write(true);
                Thread.Sleep(PotValue);
                rLED.Write(false);                
               
            }
           
        }
        static void RedCheck()
        {
            OutputPort CheckLED = new OutputPort(Pins.GPIO_PIN_D0, false);
            InputPort button = new InputPort(Pins.GPIO_PIN_A2, false, Port.ResistorMode.PullUp);

            bool buttonstate = false;

            while(true)
                
                buttonstate = !button.Read();
                CheckLED.Write(buttonstate);
    }

    }
}

Thank you for your input.

Edited by Chris Walker, 03 November 2012 - 10:01 PM.
added [code][/code] tags

[Mario Vernari]

Your code seems okay. Isn't that the "unreachable code" is just a simple warning instead? A warning shouldn't block the program execution. Cheers

[patduino]

Look at the while loop in your RedCheck function. You want to use curly brackets around the two lines that should be in the loop. The while(true) is only looping through the one line that follows it, not both. The second line will never get executed, thus being unreachable. Your "check" LED probably doesn't work, does it? - Pat

[NooM]

you have to write: while(true) { // our code here } <- all from here on never gets executed

[Chris Walker]

As Pat noted, the following line of code isn't in your while(true) loop...

CheckLED.Write(buttonstate);

If you put curly braces around those two lines of code, they'll both belong to your while loop...and things should start working properly.

BTW, I would avoid having tight loops like that on a background thread. I would recommend adding a "Thread.Sleep(1)" inside that loop so that the other threads, such as the main thread, don't have to wait a few milliseconds for NETMF to force a thread-switch. Otherwise your application will be sluggish.

Chris

[Nevyn]

Just wondering if you would be better using an InterruptPort instead of RedCheck that way you do not have to use threading. Regards, Mark

[ncsteinb]

Thank guys! I wrote the code late at night, and totally missed the curlies.... It works very well now.