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STM32f407vgt6 stlink v2 not connecting on PCB

jlaufer
Associate III

Hello! I've designed a PCB using STM32F407vgt6 but I cannot get it to connect using ST-LINK/V2 via the SWD interface. When I try to connect using STM32 ST-LINK Utility, I get the following error: 

Can not connect to target!
"Connect Under Reset" mode from Target->Settings menu and try again.
If you're trying to connect to a low frequency application , please select a lower SWD Frequency mode from Target->Settings menu.
No target connected


Neither suggestion in the error message solves the issue.

I have confirmed the ST-LINK/V2 adapter works because it connects to STM32F407-DISC1, which also uses STM32F407vgt6, using STM32 ST-LINK Utility and ST-LINK/V2 via SWD with no issue.

I've confirmed that the SWDIO pins, power, NRST and BOOT0 and BOOT1 are connected correctly per the wiring diagram using a multimeter and inspected all other solder joints and they all look okay. I also tried adding in 10K pullups to 3.3V on SWDIO and SWCKL but it didn't help so they are removed in the picture.

As far as "signs of life" tests USART2 is exposed instead of USART1. If at all possible I'd like to figure out what's wrong before ordering new boards.

Also the board uses crystal ECS-80-10-33-CGN-TR3 (CRYSTAL 8.0000MHZ 10PF SMD).

 

mcu design.png

pcb.jpg

1 ACCEPTED SOLUTION

Accepted Solutions
TDK
Guru

FB1 isn't there, so VDDA isn't powered. It's not going to boot up without VDDA. It's not optional.

TDK_0-1740441160496.png

 

Could be other things.

If you feel a post has answered your question, please click "Accept as Solution".

View solution in original post

3 REPLIES 3
TDK
Guru

FB1 isn't there, so VDDA isn't powered. It's not going to boot up without VDDA. It's not optional.

TDK_0-1740441160496.png

 

Could be other things.

If you feel a post has answered your question, please click "Accept as Solution".
jlaufer
Associate III

Thank you! Since I'm not using the analog peripherals, can I simply add a jumper across FB1, or is proper filtering required?

A jumper will work if all you want is connectivity.

If it's still dead, measure VCAP voltages. Soldering looks a bit questionable, might want to recheck for bridges or cold solder joints. Measure voltages on the pins themselves if you can.

If you feel a post has answered your question, please click "Accept as Solution".