Ethernet Shield 2 not working with Arduino UNO Minima

Hardware UNO R4 UNO R4 Minima
22

Hello Juraj,

I did, still not working.

What is disappointing is that even the fact I provided everything I did not get any support from the Arduino Development Team.

Thanks

Osiris

23

there is not much to support. it should work without problems. I have Uno R4 WiFi and it works without problems with two different Ethernet shield I put on it. And there should be no difference between Minima and "WiFi" in this.

but from you description, you do something unusual. like disconnecting the running Uno from the USB to continue on external power supply

24

Hi Operez06,

I have the similar problem, I have a program working fine on R3 + ethernet shield and not having the same behaviour on R4, so definitely there are some differences between them.

What I had tried is below:

  1. Upload the code and borad restarted > works OK > re-seat the USB cable > got a return message no shield was found.

So end it up I have to add a delay 500ms in the setup, it only works if you put it before Ethernet.begin.

  1. Then move on to test it on a standalone power, tried differnt way and I found that I lost connection to ethenet shield when there is no serial monitor, I tested it by just closed the IDE, it's still working but once I re-seat the USB, it failed again.

So thought that while (!Serial) loop is waiting and after I delete that lines, everything works fine.

That serial com check doesnt cause any issue on R3!!!

25

I'm having a similar issue with the Arduino Uno R4 Minima. I'm trying to make a simple server using Ethernet to send and receive messages, but nothing happens in the if(client){} section. Even when I can ping the UNO and connect as a TCP client, the board doesn't recognize a client connection. I even tried the example web server sketch and that doesn't work either.

26

So after chasing my tail for a couple of days here's what I found... Make sure you make pin 4 an OUTPUT and set it high. This is the SS line for the SD card. Without this that floating line will allow random collisions on the shared W5500/SD SPI bus as the SD hardware thinks it's been enabled (low on pin 4) at times. Especially if there's actually an SD card inserted.

After finding this and fixing it the combo of the Minima and Enet V2 shield works wonderfully together and under constant load.

27

only if the card is inserted. the card is the device, not the holder.

but this thread was about problems when powered over barrel jack. with USB there was no problem.

28

I did find intermittent issues as I described when powered over usb. That is my test case. And I was able to repro with multiple enet v2 shields with multiple maximas. Fwiw. But I thought I saw failures with no card in place. Reran the tests and you're right. Only with the card in place. I actually thought there was an external tristate buffer.