STM32F401RET6U Custom Board Schematic Review Request

[Rohith cyton]

Hello STM32 Community,

I am developing a custom board based on the STM32F302R8T6 MCU. My schematic is largely derived from the MB1136 evaluation board reference design, and I would appreciate a review from experienced STM32 users before PCB fabrication.

I would like feedback on the following areas:

1. Power Supply Design
   • VDD, VDDA, VBAT, VSS, and VSSA connections
   • Decoupling capacitor placement and values
   • Analog supply filtering
2. Clock Circuit
   • Main crystal oscillator connections
   • 32.768 kHz RTC crystal circuit
   • Load capacitor values and recommendations
3. Boot and Reset Circuit
   • BOOT0 configuration
   • NRST pull-up and reset button circuit
   • Any missing protection or filtering components
4. Programming and Debugging
   • SWD interface (SWDIO, SWCLK, NRST, SWO)
   • Compatibility with ST-LINK
   • Ability to program and debug reliably
5. GPIO Connections
   • Review of user button, status LEDs, buzzer, and external interfaces
   • Any pins that should not be used for GPIO due to boot/debug functions
6. General Design Review
   • Any schematic mistakes or missing components
   • Recommendations based on STM32 hardware design guidelines
   • Potential issues that could affect flashing, debugging, startup, or long-term reliability

From my initial review:

• STM32F302R8T6 is powered from 3.3 V.
• SWD connector includes SWDIO, SWCLK, NRST, and SWO.
• BOOT0 is configured through a switch/jumper arrangement.
• External 32.768 kHz crystal is connected for RTC operation.
• Multiple decoupling capacitors are placed on VDD pins.
• SWD signals and reset are routed to the programming header.

Could you please review the schematic and let me know if there are any issues related to:

• Flashing/programming
• Power integrity
• Clock startup
• Reset/boot configuration
• STM32 hardware design best practices

Thank you for your time and support.

[mƎALLEm]

Hello ​@Rohith cyton and welcome to the ST community,

1- You kept VBAT floating while it should be connected to VDD if the backup domain/RTC are not used.

2- I don’t recommend to connect directly the buzzer on the GPIO, use a transistor to drive the buzzer:

3- You can refer to the application note AN4206 “Getting started with STM32F3 series hardware development”

4- You need also to check the compatibility of the 32K crystal you have used (ABS25-32.768KHZ-6-T): see How to select a compatible crystal and load capacitors for STM32 with layout guidelines

Hope that helps

[ahsrabrifat]

First, the title says STM32F401RET6U, but the post mentions STM32F302R8T6. Make sure the exact MCU part number is consistent, because power pins, oscillator pins, boot options, and alternate functions may differ.

Also, if you want a proper schematic review, it would help to share clear screenshots of the power, clock, reset/boot, and SWD sections directly in the post. Many people will not download a full PDF just to inspect a few critical areas.

Helpful resource: https://www.pcbway.com/blog/PCB_Design_Tutorial/Tutorial__How_to_Design_Your_Own_Custom_STM32_Microcontroller_Board.html