No STM32 target found - STM32L486 sanity check

[CraigORV]

I've recently put together a new design and ST-Link doesn't seem to detect the STM32L486 on the board using the STM32CubeProgrammer

The part used is the 144 LQFP version, but I've double checked the pins and connections for the SWD port. I'm supplying the microcontroller with 3.3V, but powered up is sitting at 3.2V strangely. Strangely I'm noticing some shorts from other pins to the 3v3 rail from some GPIO pins (PA2, PF2, PF11) and I'm not sure if this is normal when the device is unpowered.

Does anyone have any idea what might be the problem here? Schematic below

[TDK · Accepted solution]

> Strangely I'm noticing some shorts from other pins to the 3v3 rail from some GPIO pins (PA2, PF2, PF11) and I'm not sure if this is normal when the device is unpowered.

No, this is not normal and indicates a hardware issue.

It sounds like the part orientation is off by 180 degrees.

Pin 1 is on the bottom-left when the text is read from left to right.

[CraigORV]

Thanks, silly mistake, but that was it. For some reason I hadn't realised there was an additional witness mark on the chip, which is a little confusing since it's similar to the pin1 marking!

[Tesla DeLorean]

This is one of those recurring issues..

https://community.st.com/s/question/0D53W000012UwA9SAK/ambiguous-lqfp100-pin-1-markings

https://community.st.com/s/question/0D50X00009Xka68SAB/stm32f401-64pin-pin1-marking-orientation