Problem with Ethernet Shield (WIZnet W5100) and 'ghost' COM port

Using Arduino IDE 1.x
1

Hello, everyone. I've searched the forum but didn't found anything like that, so I'll describe the problem:

I'm trying to use the WIZnet W5100 Ethernet shield, but every single time I reconnect the Arduino + shield on my laptop, COM4 (which is being used to upload Arduino sketches) simply vanish. Tried to reset it to solve, no success. If I detach the shield, COM4 comes back from the dead.

I'm using an Arduino Duemilanove with ATMega 328, I've bought the shield last year (only now I had time to play with it), my laptop is running Win7 x64 and I'm using Arduino 1.0.

Don't know what else I may do. :~

PS: And I didn't even tried to use the SD Card yet...

2

Which ethernet shield are you using? There are several models. Here is a list of "official" ethernet shield models.
http://www.smallshire.org.uk/sufficientlysmall/2012/01/01/an-atlas-of-arduino-ethernet-shields/

There are also "unofficial" models available on eBay.

3

The shield model is Ethernet Shield 05 (V2.0).

4

How about trying this. Remove the shield. Upload the following sketch. Replace the shield. Open the serial monitor. Does all work ok? Does the pin13 led blink once a second and "Tick" on the serial monitor?

void setup()
{
   Serial.begin(9600);
   pinMode(13,OUTPUT);
   Serial.println("Setup finished");  
}

void loop()
{
   Serial.println("Tick");

   digitalWrite(13,HI);
   delay(500);
   digitalWrite(13,LOW);
   delay(500);
}

edit: I don't expect the serial monitor will be active if the serial port is not showing up. The blinking led is what I want to check.

5

Without shield the LED blinks and the serial monitor ticks, as expected. With the shield just the LED works, no serial monitor.

6

Are you a gambling man? I am. I'll try about anything, so you will have to decide what you want to do.

The only thing that I can see that would block the usb port would be digital pins 0 and 1. If the shield blocked the signals on those pins, that is about the only thing that would interfere with the usb port.

I would try a little "pin bending" as a test. I would bend the pins only as far as necessary, and bend digital pins 0 and 1 on the shield so they do not insert into the Arduino header. Then I would try it again. But that is me...

7

I'm a poker player, gambling is in my blood. :slight_smile:

I'll try this and return the result when possible.

And thank you for your time. :slight_smile:

8

I'm a poker player, gambling is in my blood.

I like you already, Vinny! :slight_smile:

Let me know how it goes. I have seen this complaint on other ethernet shields, and suggested this, but nobody has reported back whether it worked or not. Your report may help others.

9

No help, didn't work. :frowning:

But I believe I've found the problem: after a close look, I think I saw some solder jumpers between W5100 pins. I've counted 8 of these. And I have pics:

The first picture isn't very clear, but the second one you can clearly see the solder jumpers. I'll have to check the board schematics and desolder the pins that shouldn't be united. Problem: never reworked SMD components in my life. =/

Thank you for your help anyway. :slight_smile:

10

That looks like it. Pins solder jumpered is not a good thing.