Help a novice decide on a circuit design for ESP32/W5500

Question

Hello! I am pretty new to embedded systems, so please bear with me! I know very little about electrical engineering at all. However, I was able to design a functioning prototype board that just has to take network requests and run some voltages through mosfets based on those requests. My circuit is based around the esp32-s3-wroom-1. The existing prototype used an esp32 devkit and the usr-es1 (https://www.pusr.com/download/ES1/USR-ES1-EN-V1.0.pdf). For this revision I want to break out these modules into base components. I’m trying to sort out the best way to do that based on the reference schematics provided by wiznet. I really just want it to work exactly the way it does now since I haven’t had any problems with the module. I’m not doing any configuration really, just hooked everything up and used the esp-idf eth library. I suspect that this is the closest reference schematic to what I actually want: docs.wiznet.io w5500_sch_v110_use_mag_.pdf 44.02 KB However, I actually pulled apart one of my usr-es1s and noticed some differences in the circuit. I put these images together to show what I’m talking about: w5500 breakdown3800×600 82.4 KB w5500 breakdown2800×600 88.9 KB w5500 breakdown1800×600 89.6 KB These are the under side of the board which I mirrored and inverted so I could adjust the opacity and overlay it on the top side, the top side with all components removed, and the top side with the components in place. The yellow lines are the traces on the bottom. The main difference I’m noticing between this board and the reference schematic is the power circuit. Everything attached to pin 37, RSTn, behind the 103 resistor. Also the oscillator seems to be missing a few pins and components from the reference schematic. The additional stuff in the power circuit sort of lines up with those components, but I don’t think they are related here unless I’m totally misunderstanding something. Anyway, I suspect you may tell me to ignore these differences and just use the reference schematic. If that is the case, is the pdf I linked the correct one to use? The usr-es1 uses the first PMODE. That’s probably what I should do as well, right? If this is not exactly how I should design my circuit for a drop-in replacement for the usr-es1, is there another reference somewhere that is closer, or what changes should I make (seems like there should be a kicad file floating around somwhere)? Additionally, do you have any general things to keep in mind when designing the schematic and pcb aside from the notes listed in the pdf? This will certainly be the most complex part of my design since I don’t have high speed communication anywhere else. Also I must apologize in advance because I know very few electrical engineering terms beyond the basics (resistor, capacitor, impedance, etc). Thanks very much, I know this is probably a much more basic question that you are used to here. I really would appreciate any help I can get.

munderwoods · Answer

I now suspect that the extra components in the power circuit or for converting 3v3 from digital to analog. Since I am using an esp32-s3, I don’t have analog output. I can’t really tell what components these are, so anyone know a circuit I could use to accomplish the same thing?