The output of IO5 of EMX is very weak

I have built a board on the basis of “FEZ Cobra Mainboard”.

I have tested all GPIO Pins, I find the signal of IO5 is very weak. the test code is as follow:

using System;
using System.Threading;

using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;

using GHIElectronics.NETMF.FEZ;

namespace Outputporttest
    public class Program
        static OutputPort led1 = new OutputPort((Cpu.Pin)FEZ_Pin.Digital.IO19, true);
        static OutputPort led2 = new OutputPort((Cpu.Pin)FEZ_Pin.Digital.IO5, true);
        static OutputPort led3 = new OutputPort((Cpu.Pin)FEZ_Pin.Digital.IO7, true);
        static OutputPort led4 = new OutputPort((Cpu.Pin)FEZ_Pin.Digital.IO45, true);
        public static void Main()
            int i = 0;

            while (true)
                if (i == 0)
                    i = 1;
                else if (i == 1)
                    i = 0;


I have checked the signal of these 4 pins with oscilloscope.
IO19, IO7 and IO45 work well, but the signal of IO5 is very weak.
Is it Hardware problem or software problem?

When you say “weak”, do you mean the voltage is low?

IO5 is used by the TFT display, are you currently using that?

I have just tested this and you may be right, however, since I am not 100% sure of this, I am passing this issue on to a higher-level engineer so that they may test it as well.

@ godefroi -

yes, I mean the voltage is very low.
The the IO5 is used for touch funktion of display. but I don’t use the touch funktion of display, the IO5 is not connected with display.

@ James -

hi, my colleague has checked my board today, and the bord is soldered by himself.

he has soldered the IO5 of EMX on my board again, and IO5 works well now. I think I have solved the problem

In my board the IO5 works as “CS/” for a mutiplexer and the amplitude of IO5 is 0.36V now. I have checked IO5 with oscilloscope.

You said, that you have also tested the IO5 and there is the same problem as mine 2 days ago. If you slove it, please let me know it.

Anyway I thank you for your help!!