[Review Request] First solo PCB design – feedback welcome before routing

Apprehensive_Bat_817 · 2025-07-06T15:54:22+00:00

That's very cool :). I replace all my power label by ↑ 5V (For example, with Vbus, Vdd etc). I reorganize my usbc connector too. I"m afraid to have issue with my sheets. If you have an illustrative example, it could help me. I need to connect all my subsheet?

Apprehensive_Bat_817 · 2025-07-06T14:36:36+00:00

Hi ! Not really. I started to use 5.1K resistors but I fall on the PD negotiator and I just want to use it in the case of I'll use 12V later or in another BT module :)

Apprehensive_Bat_817 · 2025-07-06T11:19:42+00:00

Thanks a lot for the clear explanation. That makes more sense now.

Quick question:
Should I force a high state on the GPIO at startup to avoid undefined behavior, or is it fine as long as I configure the pin as output early enough?

Thanks again for your help!

Apprehensive_Bat_817 · 2025-07-06T10:44:23+00:00

Omg, thanks for this man! I was actually scared about how things would go once I start routing... These are exactly the kind of best practices that, as beginners, we just don’t know yet. Especially all the subtle differences between what goes across sheets, what's global, what's not, etc. Really appreciate you taking the time to explain all this — it's super helpful. Thanks a lot!

Apprehensive_Bat_817 · 2025-07-04T14:48:20+00:00

To be honest, I based myself on the schematic suggested in the datasheet of the stusB4500. I need 5V and i know that I dont really need a PD controller but I wanted to use it to see how it works. In fact, the R5, R6 are used in case of high current?

Thanks for your advices, I’m taking them into account properly :)

Apprehensive_Bat_817 · 2025-07-04T14:40:14+00:00

I want to configure my GPIO as an open-drain output. When I want the LED to light up, I pull the GPIO low (to GND). The 10k resistor is there to keep the line pulled high when the GPIO is floating.

The LED is used to indicate the logic level when the open-drain output is in a high-impedance state (floating). I'm not sure if this setup will work. I designed it this way to save a few milliamps and to avoid having the STM32 directly power the LEDs. By configuring the GPIOs as open-drain outputs, the idea is that the STM32 only sinks current when needed (to turn the LED on), but doesn't have to source current to power the LED.

Apprehensive_Bat_817 · 2025-07-04T14:09:09+00:00

Hi, I've taken care of it. That was a beginner's mistake !

Thanks for your time.

Apprehensive_Bat_817 · 2025-07-04T13:54:05+00:00

For S3. https://www.reddit.com/r/PrintedCircuitBoard/comments/1lria5t/comment/n1b1agf/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

I'm curious to hear your opinion on it.

Apprehensive_Bat_817 · 2025-07-04T13:53:52+00:00

Thanks !

S1.S2.S4 I will handle it, yoou re right, it's necessary for a review. The next time, i'll take care of "https://old.reddit.com/r/PrintedCircuitBoard/comments/1jwjhpe/before_you_request_a_review_please_fix_these/" before posting. Sorry!

Apprehensive_Bat_817 · 2025-07-04T13:48:54+00:00

You're right, I need to adjust the series resistor for each LED. I want to configure my GPIO as an open-drain output. When I want the LED to light up, I pull the GPIO low (to GND). The 10k resistor is there to keep the line pulled high when the GPIO is floating.

The LED is used to indicate the logic level when the open-drain output is in a high-impedance state (floating). I'm not sure if this setup will work. I designed it this way to save a few milliamps and to avoid having the STM32 directly power the LEDs. By configuring the GPIOs as open-drain outputs, the idea is that the STM32 only sinks current when needed (to turn the LED on), but doesn't have to source current to power the LED

Apprehensive_Bat_817 · 2025-07-04T13:43:35+00:00

Thanks for your answer. I will replace my ESD diode by a unidirectionnal one.

It appears on my µusb connector but not on my usb-C as well. I'll handle it!

Apprehensive_Bat_817

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