WIZ550io ok, WIZ850io totally unreliable

Question

I’m still trying to debug my WIZ850io module. As a test, I purchased and installed a WIZ550io module on an identical test setup (STM32F103C8T7 running STM32 Arduino core). The WIZ850io crashes after about 30 minutes, the WIZ550io has been running for over 48hrs. I see that there are capacitor and resistor differences between the 850 and 550. There are obviously layout difference too, including some interesting traces from pins 1&2 and pins 5&6. Those traces have a bend, is this to match trace length? Thanks for your continued support, IK

irina · Answer

W5500 is used to both WIZ550io and WIZ850io. If you operate both products at the same time, the MAC address must be different. 2.If you are possible,Could you please draw the connect schematic? Also how did you connect the power? Currently, the hardware engineer is on vacation and he will answer you next Monday.

indridkold · Answer

Hello and thanks for your response. With further experimentation, we have discovered that the WIZ850io module is VERY sensitive to electrostatic field (NOT electrostatic discharge, just the field). I can create a charge by getting up from my chair, and the 850io fails every time. No contact with the 850io (or anything else) is made. No spark is generated. The 550io continues working. The 550io sits beside the 850io on my desk and has continued running for over 48hrs. I do not think the problem is with the W5500 chip. It seems the issue is with the layout of the 850io module. It is a very strange problem! I have never seen a device this sensitive to electrostatic field. I have verified that the MAC addresses are different. The WIZ550io module has a built in MAC which we are using. Overnight the office is quiet and the 850io module will run overnight. It crashes when I sit down at my desk in the morning! I will draw a schematic and attach photos of our test setup. Once again, thankyou for your continued support, IK

mare · Answer

Having similar problems with WIZ850io module. Any ideas to mitigate the ESF??