STM32 Custom Sensor PCB – Schematic Review Before PCB Layout

[pln]

I am currently designing a custom sensor PCB for an underwater ROV project using an STM32 (STM32G431CB). This is my first complete PCB design, so I would like to get feedback before moving on to the PCB layout stage.

The board is intended to act as a sensor interface and control unit, and includes:

IMU (BNO08X)
Depth/pressure sensor (analog)
Multiple analog leak detection sensors
ESC control via PWM outputs
UART communication with a Jetson Orin Nano
3.3V regulation using an LDO (LP2985-3.3)

The system is designed to operate in an underwater ROV environment, so reliability and noise robustness are important.

Before starting PCB layout, I would really appreciate a review of my schematic.

Could you please help me with:

Identifying any design mistakes or missing components
Checking power distribution and decoupling strategy
Verifying STM32 minimum requirements (BOOT, NRST, SWD, etc.)
Any suggestions for improving robustness in a noisy environment

I have attached the KiCad schematic for reference.

Thanks in advance!

[pln]

[TDK]

If PB8/BOOT0 is grounded, what is the "BOOT0" net supposed to do? Doesn't appear to be connected anywhere. It certainly is not controlling the state of the BOOT0 pin.

R2 is doing nothing useful here as far as BOOT0 goes.

PG10/NRST should have a 0.1 uF cap to ground (not 3V3) directly at the pin. What you have may work fine but doesn't follow the recommendation. R1 is not needed. Put a series resistor between the button and the capacitor if you want.

Everything else looks good!

[LCE]

4.7k series resistors for I2C at J5 might be a little too much - but it's only resistor values, so it doesn't really matter for the PCB layout.

Or these high values for protection because there's 5V at J5 ? 
It will be simpler if the device connected to 5V will have a 3.3V LDO. Otherwise you better use a voltage level translator. (In case of a slow I2C bus you might get away with some smart pull-up / series resistor combination)

[Andrew Neil]

Have you checked-out Application note AN5093, "Getting started with STM32G4 Series hardware development" ?