WIZ850io module activity LED always on.

ok I’ve got a couple of captures. Device talking to the pc running wire shark through 2 network switches. Once the connection is lost in this case unplug the network cable we will see a tcp retransmission from the server, then when the cable is plugged back in and the act led goes solid we will begin to get TCP spurious retransmissions.

It will continue with the spurious retransmissions even after we reset the device. Once we do a full power down and back up it will begin working again. otherwise I really don’t see anything strange in wireshark until we get it in this mode.

The screen shot does not list some packets (look at No.). The visible list should not cause ACT LED lit. Please dive into remaining packets, especially those appearing on the W5500 interface side.

I filtered the traffic to only the device ( and server ( and I agree I don’t see anything that would keep the act LED on continuous. I have hooked the device into a switch with nothing else connected while it is in this state and the act LED will stay on. That is why this is so strange. BTW Eugeny than you for your time on this :slight_smile:

Thank you. I am out of constructive ideas so far, the only comes to mind is try change every module changeable (e.g. power supply with another type, processor with another board, cables etc) and blindly look at differences.

I am inclined to think there’s something wrong with the modules (WIZnet will not like it!). I think modules are produced on the contract, thus even if WIZnet makes good chips they may be defected down the road - manufacturer of the board, then handling, then when using… The obvious thing is that as soon as you have several modules behaving the same way either we do something wrong to the module, or something wrong with the module.

So summarizing: W5500 enters the mode when:

  • if it is connected to switch with no other devices connected to it, it flashes ACT LED, and there’s no traffic on the wire;
  • stopping SPI communication does not stop the flashing (thus it is not software doing something to the chip);
  • only power cycles cures. Hardware/software reset makes no difference.

you Summary is correct except the ACT LED stays on solid not flashing.

  • if it is connected to switch with no other devices connected to it, ACT LED on SOLID, and there’s no traffic on the wire;
  • stopping SPI communication does not clear the ACT LED(thus it is not software doing something to the chip);
  • only power cycles cures. Hardware/software reset makes no difference.

At this point I think we may have to look at a different solution. I haven’t been able to get a support reply. I hate to do since this was a perfect fit for what we were trying to do. Eugeny thank you for you help on this.

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well I haven’t given up quite yet. after reading through the forum I found this thread: High temperature and high consumption

the state of the ACT LED isn’t mentioned but the W5500 was getting in to a funky state. I have modified teh WIZ850io to remove the ferrite bead between AGND and DGND and changed the damping resistors to 0 ohms. Now we haven’t been able to get the W5500 stuck in the funky state with the ACT LED on constantly. I am not going to call this fixed yet. We are going to stress the unit for a few days and see what happens.

If this works we will just add the W5500 to our boards instead of the WIZ850io and a way to power cycle the device from the micro. Fingers crossed.

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Hello forum,
we are using the WIZ850io modules on our board since 2016 and have used some hundreds of them without problems.
But with the last bunch of about 50 boards we have on many of them exactly the same wired behaviour of the WIZ850io module that was discussed in this thread.

After a undetermined duration of normal function the WIZ850io stop working:

  • Activity LED and Link-LED are permanently on
  • No stable ethernet communication to host pc is possible
  • Ethernet communication traced with wireshark shows many retransmits

If i disconnect the ethernet cable:

  • Activity LED and Link-LED are off

If i reconnect the ethernet cable:

  • Activity LED and Link-LED are immediatly and permanently on

Holding the reset pin low for many seconds:

  • Both LEDs are off

After releasing the reset pin with cable connected:

  • Activity LED and Link-LED are immediatly and permanently on

Only a power down/up can bring the WIZ850io module back to normal operation.

Unfortunatly we do not know how we can reproduce this wired behaviour. It happend undetermined, and so we can not select good modules.

Was there any change in hardware in 2019 to the WIZ850io module, because with the older modules we have not seen such as wired behaviour?

Are modules geniune?

When cable is reconnected the round of negotiations must be performed (I guess unless you hardwired the W5500 to specific configuration through PMODE pins) , and if there was PHY error, it is usually cleared. In your case it is not, thus the problem can easily be outside of the W5500 (but can also be interoperability issue). Any changes in infrastructure (e.g. using new models of hubs/switches)?

As test:

  • reset driving microcontroller, but not W5500. This way we will check how activities from MCU affect this behavior of W5500;
  • after this happens, plug another netowrk cable to the W5500, but with guaranteed no traffic (e.g. standalone hub with only one device - W5500 - connected to it). This way we check if the issue is caused by the storm in the wire.
  • Yes, the parts are genuine.

  • No changes to the infrastructure, same type of netgear 100M ethernet switch used .

  • Holding our microcontroller in reset dosn’t change the behaviour of the WIZ850io module.
    If the WIZ850io module is in the wired state (both LEDs are permanently on) after some hours of normal working:
    – Holding our microcontroller in reset:
    → nothing change, both LEDs are premanently on
    – our MC is permanently in reset for the next steps.
    – Disconnect the ethernet cable:
    → both LEDs changing immediatly to permanently off
    – Reconnect the ethernet cable, with no other connections to the ethernet switch:
    –>both LEDs changing immediatly to permanently on
    – PowerDown/Up to the board and holding our MC in reset and no powercycle to the ethernet switch:
    –>WIZ850io module behaviour is returned to normal operation

What is the temperature of the chip? What is exact power supply voltage? Can you measure the current being consumed in normal and in this this faulty condition?

Can you confirm that in this condition communication is possible, however unstable?

Can you perform changes mentioned by @Lon_Hemmen in his last post - ferrite bead and damping resistors, or at least check that they are of correct value? In general - inspect the board with the magnifier and compare its components to the circuit diagram.

  • Chip temperature: i don’t know, because it is not accessible. Ambiente temperature is about 30°C

  • Powersupply voltage is about 3.3V, and it must be > 3.15V, because our MC is running and we have a supervisor IC with a threshold level of 3.15V

  • No i can’t measure the current consumed by the WIZ850io, but it will not be the 700mA mentioned in the thread High temperature and high consumption , because our 3.3V linear voltage regulator can’t provide so much current.

  • No i can’t check and change the damping resistors and the ferrit bead, because the WIZ850io is soldered on our board and so the parts are not accessible for me

I have the problem that i don’t have a test-setup where i can reproduce the failure, do some changes and check again.
The WIZ850io modules are part of our testsystems that is running at our customers a few 100km away from me. And the ethernet failures are stopping the testsystems and this is not practicable for our customers. So for a workaround, we have changed the communication from ethernet to USB, because the motherboard for the WIZ850io has also a USB interface.

I don’t understand why we have not seen such problems in the past. Our hardware has not changed, and also the environment has not changed.

i have problem
led always on
could you tel me how can solvemy problem step by step?

could you help me ?

Hope you solved your problem already. If not, you need to provide details on what setup you have, and you tries so far, and what software does with the chip.