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Can't connect to STM32F412 with SWD

ABuja.1
Associate II

Here is my schematic and board. I'm wondering if someone can verify that I have everything that's needed on the stm32f4. I can't connect with SWD to the core. My JLink tries multiple times and fails. When I press the reset button on my board the JLink's LED turns red so it seems that the connection between my board and the JLink is correct.

I've found a mistake in my crystals' capacitor values, but I don't think that should cause this issue?

1 ACCEPTED SOLUTION

Accepted Solutions
TDK
Guru

Big issues:

VSSA needs grounded.

VDDA needs connected to VDD.

Smaller issues:

The capacitor on VCAP should be 2.2uF or 4.7uF.

The load caps for X1 (8MHz crystal) almost certainly shouldn't be 0.1uF. Probably closer to 10uF. Probably true for X2 caps as well.

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

View solution in original post

4 REPLIES 4
TDK
Guru

Big issues:

VSSA needs grounded.

VDDA needs connected to VDD.

Smaller issues:

The capacitor on VCAP should be 2.2uF or 4.7uF.

The load caps for X1 (8MHz crystal) almost certainly shouldn't be 0.1uF. Probably closer to 10uF. Probably true for X2 caps as well.

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

Thanks, I'll try connecting VSSA and VDDA and see if it works.

Are you sure about the load cap values? In the datasheet it seems to recommend 5pF to 25pF

Oops. I meant 10pF, not 10uF, for X1 caps. Not real sure for X2, but definitely in the pF range.
If you feel a post has answered your question, please click "Accept as Solution".

I tried on a blank board with a new chip, and connected vdda and vssa and it worked, thanks!