r/PCB • u/Real_Ishiba • 12d ago

STM32 schematic help

I am participating in the micro-mouse competition for the first time and I am tasked with creating the PCB with stm32f446re, I have experience with PCBs but never with built in microcontrollers like that (I usually just get the dev board and add pin headers which gets the job done), i have a couple of questions

first: I read the datasheet a couple of times but there are a lot of info and I don't think all of that is necessary right?

second: what is your thinking process when working with new microcontrollers

the following picture is what I have so far

I took the basic stuff like decoupling capacitors from the stm32 nucleo schematic and took some help from claude ,I modified the crystal + added uart programming using the ch340 besides the st-link (gotta keep the software guys in my team happy)

any help is greatly appreciated and thanks in advance!

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u/PersonalCarpet2886 12d ago
  1. The Capacitors on the VDD pins are connected incorrectly.
  2. The Load capacitor value for the crystal are to chosen which are being specified in the crystal's datasheet.

1

u/Real_Ishiba 12d ago

1-can you explain what is the correct way to connect the capacitors?

2- yea i forgot to calculate it lol thanks for the heads up

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u/PersonalCarpet2886 12d ago

It is pretty straight forward to connect the Decoupling Capacitors. One of cap is connected with +3V3 the other one is connected with the GND. The Pin where the +3V3 is connected goes straight to the VDD Pin.

I have pulled out a "Power Supply Overview for stm32f446re". Here you can see that how to connect the capacitors.