The output of IO5 of EMX is very weak

Archive
1

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)
                {
                    led1.Write(false);
                    led2.Write(false);
                    led3.Write(false);
                    led4.Write(false);
                    Thread.Sleep(50);
                    i = 1;
                }
                else if (i == 1)
                {
                    led1.Write(true);
                    led2.Write(true);
                    led3.Write(true);
                    led4.Write(true);
                    Thread.Sleep(50);
                    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?

2

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

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

3

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.

4

@ 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.

5

@ 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!!