There is a mistake with wiz55io module sch

TCP/IP Chip W5500
1

upload 3 picture from datasheet.

That means you can’t RESET the chip by set J2-3pin LOW.

I’ve tested for sure.

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2

Hello,

nRST_FROM_EXT pin is connected to MCLR pin of PIC inside WIZ550io as you can see in datasheet.
MCLR pin is the master RESET pin of PIC.
After asserting MCLR to LOW, PIC will be reset.
Then PIC turns W5500_nRST to LOW and HIGH after for a while by its codes. It makes W5500 be reset.

This is the reset mechanism of WIZ550io.

If you monitor nRST_FROM_EXT and W5500_nRST with oscilloscope, then you can see that after you change nRST_FROM_EXT to LOW and back to HIGH a few mili or micro-seconds later, W5500_nRST turn LOW and return to HIGH after dozen of msec.

I hope it is helpful to you.

Thank you.

James.

3

Thanks.

I understand.