W5100s and STM32 custom board SPI problem

Question

Hello, I made custom board with W5100s and STM32. The STM32 part of the board works as expected but the W5100s part does not. When I tested SPI with oscilloscope MISO is low all the time. I would like to ask you if you can see my schematics and help me find a error. thank you very much W5100S7102×4532 162 KB

Mon2 · Answer

Hi. Not sure if you have this working but from a quick review of your posted schematic: a) confirm you have applied the required filter caps for the voltage rails as noted in the datasheet b) do not agree with the hard strapping of the #RST (RSTN) line to +3v3. Instead, consider to apply an external reset supervisor to meet the timing of low for xx time then high. In a pinch, a RC circuit should be ok but best to confirm with the Wiznet staff and/or check other application notes using this controller.