STM32F303 does not boot

[DetlefS]

Hi,

I run the NUCLEO-F303RE eval board. I separated the ST-Link part from the target processor part and connected GND/TCK/TMS/NRST/SWO by wires. I populated the 8MHz xtal with Rs and Cs on the target part. 

This works fine.

I copied the circuitry for the target processor according to UM1724 documentation for my own board with populated xtal. I connected it to the ST-Link and flashed it with CubeIDE.

I read "Verifying ....." and "Download verified successfully" . So flashing seems to work.

Then I constantly get: "Target is not responding, retrying" 

The xtal is not oscillating. The target processor does nort work either with direct MCO clock from ST-Link.

I checked Vdd and GND. I checked BOOT0 pin 10k to GND. VDDA and VBAT is not applied. 

What does it need more to start?

THX Cheers

Detlef

[Tesla DeLorean · Accepted solution]

VDDA/VSSA is required. It's not just if you use ADC/DAC, but it also runs the PLL and POR circuits.

[DetlefS]

:) . Yes, was not aware of that. Bought you a coffee or a beer.

Cheers

Thanks

Detlef