Programming STM32L w/J-Link Compact

[DRkidd22]

I have created the below circuit and build a PCBA. I'm using the J-Link Base Compact and Tag-Connect TC2030.

Using the Arduino IDE I created a simple sketch to drive the 4 LEDs shown on the schematic below and blink every second.

The code compiles ok and Arduino IDE reports that it has successfully upload to the SMT32 chip, but the LEDs won't blink. I tried enableling outputs to other pins as well, but the problem persists. Any ideas what might be causing this? I'm using the Generic STM32L4 series "board" from Arduino library.

[Andrew Neil]

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@DRkidd22 wrote:

VTref is only to detect power presence? 

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Not just presence; it also sets the voltage levels of the J-Link interface - this is what lets it work from 1V2 all the way up to 5V.

So, if it's looking at the wrong voltage, then the whole J-Link operation becomes suspect.