STM32F405RGT6 custom board review

[ekremtrn]

Hello everyone, this is my first post on the forum. I'm starting to learn STM and have created a custom board using the STM32F405RGT6. This is the first board I've created, and I wanted to check for any errors before sending it to production. So I've uploaded a PDF of the connection diagram. I'd be very grateful if you could review it and let me know if there are any mistakes.

[Andrew Neil]

Welcome to the forum.

Please see How to write your question to maximize your chances to find a solution for best results.

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@ekremtrn wrote:

 I'm starting to learn STM .

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Do you have experience with any other microcontroller(s) ?

Before leaping into a custom hardware design, I would strongly recommend that you prototype & gain experience on a development board - far cheaper & easier to find & fix issues than on a custom design!

Did you study Application note AN5093, Getting started with STM32G4 Series hardware development boards?

I don't see any programming/debug connector ?

Have you considered how you will program, debug & test your design ?

See Design For Debug ...

PS:

It would also help to give details on the intended application of this board, and what environment it will operate in - these will affect the design

[TDK]

Looks okay except:

How do you plan to program/debug without a programming header?

[ekremtrn]

Thank you. I intentionally did not add a programming header because I wanted to design a small card. I plan to program it by removing the RTX and CTX from the 10-pin header and connecting it to the USB-A header with an external cable.

[mƎALLEm · Accepted solution]

Hello,

Need to re-check this part of LSE:

Did you check if the crystal is compatible with the STM32? did you calculate the gain margin based on the crystal characteristics and the load capacitors?

Read How to select a compatible crystal and load capacitors for STM32 with layout guidelines

18pf CL looks a bit high compared to the CL recommended for LSE for STM32 in the AN2867 : 

[Andrew Neil]

So how do you plan to debug it?

Omitting this capability is a Really Bad Idea!

You don't have to provide a full-sized header - could be just test points accessed with "pogo pins"; eg,

See https://www.tag-connect.com/ for that particular connector.

The absolute minimum for SWD is just 2 connections - data & clock - but it's best to also include RESET.

Again, Design For Debug !

[ekremtrn]

Thank you, you're right. Do you know where I can find the pogo pin footprint for Altium? I couldn't find it.

[Andrew Neil]

https://www.tag-connect.com/contact-us

Or try Altium support/forums

PS:

https://www.tag-connect.com/info/footprint-downloads

[mƎALLEm]

Hello @ekremtrn if your original question has been answered please "Accept as Solution" the post that answered your question. For new questions please open a new thread.

Thank you.

[ekremtrn]

Thank you. I was using a 32.768 kHz ±20ppm Crystal 12.5pF 70 kOhms 2-SMD, No Lead. I will replace it with an FC-135R 32.7680KA-AG3 and use an 8.2 pF Capacitor.