Hello,
I have used wiz850io Evaluation board with Raspberry Pi 4 and that works fine.
Later I have copied the wiz850io schematic to make my own PCB.
In the board, I forgot to connect pull-up resistors for SCSn, Int_N, and RSTn and the total impedance of the circuit was 7.5 ohm.
I have used pull-up resistors later for these Pins and impedance increase to 10k but the ethernet controller is not working. I have compared both schematics 3 times but there is not difference.
Can you please guide me how to troubleshoot???test.pdf (79.9 KB)
Hi
I couldn’t see any differences in your circuit either.
But I don’t understand for a total impedance of 7.5 ohms.
Please tell me how you measured the total impedance?
And measure whether the total impedance of the wiz850io is the same according to your measurement method.
Thanks, Bruno for your reply.
I have measured the resistance between 3.3V supply and ground of ethernet controller ground which is 7.5 ohm only.
in Wiz850io the total resistance between the above two points is 13kohm.
Thank you for answering.
Maybe the board is a power short.
W5500 chip may already be in bad condition.
After checking the problem, test it by applying it to another board.
I have checked with three boards actually. 
