ESP32 and 2xW5500 Board, design questions.

TCP/IP Chip W5500
1

Sirs, we are routing 2xW5500 on shared SPI bus controlled by ESP32, with separated ChipSelect, Reset and Interrupts, on 4 layer board (GND and 3.3V Power Plan).

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From datasheet:

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The questions (I drawed the schematic based on reference design from wiznet):

a) about the pins tied to GND using 10K resistors, pins 38 to 42. Do I need to use these resistors ? (or connect these pins directly to GND).

b) about PMODE pins tied to +3.3VDD using 10K resistors, pins 43 to 45. Do I need to use these resistors ? (or tied directly to +3.3VDD).

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2

This question on pull-ups and downs has been asked several times here, and I do not recall definite answer. My research shows that you should be able connecting these to the GND or VCC, but the advantage of resistors is your ability to remove them and connect pins differently - as test or as fix for some design problem. Second, less obvious but much less probable advantage - if chip for some reason fries you protect would-be shortage between power rails by these resistors. But I have never seen the chip fried this way :slight_smile:

3

Thanks, Mr. Eugeny.