Problem with the nRST pin in a STM32L021K4

I tried to design a simple board with a STM32L021K4 and to program it with a STLINK-v3 MINI. I got the following error message:

Error in initializing ST-LINK device.

Reason: Target held under reset.

(You can see the full logs attached, as well as the schematics)

I measured the nRST pin, and it's about 0V. I measured VDD and VDDA, and they are at 3.3V. BOOT0 is connected to GND.

I added a 100nF capacitor from nRST pin to the ground and I tried to short the inductor of the VDDA filter.

Did I miss something obvious? Did I burn something?

Do you have any idea before I waste another PCB?

This topic has been closed for replies.

Super User

Schematic/pinout looks correct. Is the part oriented correctly?

Edit: if chip is powered without debugger attached, is NRST high?

Visitor II

Thanks for your answer. I double-checked the orientation of the components before posting (I'll triple-check tomorrow just in case).

NRST is low whether the stlink is connected or not.

Super User

Post a high resolution picture of the board if you can.

Visitor II

I didn't manage to take anything usable.

However, I assembled another board, and got it working.

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