Custom Board Review Based on MB997E .

[rohithinthingstech]

Hi ST Community,

I have developed a custom board based on the MB997E evaluation board as a reference design.

1. Could you please help me review my custom board design and schematic to identify any possible mistakes.

2. In my custom design, I have also added an external 32.768 kHz crystal oscillator for the RTC function.

• Is the connection correct?

• Are the load capacitors and routing appropriate?

• Do I need to make any changes to ensure stable operation?

I am attaching my schematic Any suggestions or corrections would be very helpful .

[NesrynELMK]

Hello @rohithinthingstech 

The schematic appears to be correct.

I recommend referring to the application note AN4488: Getting Started with STM32F4xxxx MCU Hardware Development for comprehensive guidance. You can access it here:
https://www.st.com/resource/en/application_note/an4488-getting-started-with-stm32f4xxxx-mcu-hardware-development-stmicroelectronics.pdf

This document provides valuable insights and best practices that will help ensure a robust hardware design for your STM32F4 series MCU.

Br,

[Andrew Neil]

Why the divider?

(and similar on BOOT0)

You just need a pull-up or a pull-down.

Are you sure you want them both pulled high?

Just a style issue:

This could be better titled "SWD" and, as you're just using SWD, use the SWD names - rather than JTAG names

[Peter BENSCH]

In addition, there is no 0.1µF capacitor on the NRST, as stated in the AN4488, section 3, mentioned by @NesrynELMK (the pull-up resistor that was common in MCUs of the last millennium is NOT necessary because there is already an internal pull-up).

Regards
/Peter