Unable to Connect to Custom Target STM32F412CEU6 via SWD

[ashishkv29]

Hi , I am also making custom board for GPS, and same issue I am facing, unable to connect via SWD, Please help to debug.

[caneralp]

Remove the diodes on the debug port, it will work. 

[ashishkv29]

Removed all 4, but still same issue

[Andrew Neil]

How are you trying to connect and how, exactly, is it failing? Show logs & screenshots.

Has this board ever worked?

If it's brand new, have you checked basics: power supplies; component orientations; current draw; etc?

You don't have NRST on your debug header; Have you tried adding that, and then connecting under hardware reset?

How to solve connection errors when connecting and programming the STM32 target board.

How to solve debugger connection issues

[ashishkv29]

How are you trying to connect and how, exactly, is it failing? Show logs & screenshots.

Ans: Connected ST-Link v3 SWDIO to MCU SWDIO and CLK to CLK, and GND and VCC from MCU Board.

ST-Link Log

Traces and Component Placement :

 Red is top layer and Blue is Bottom layer

 Schematic:

Board Stackup:

Also maintaned impedance for signal = 50 and for CAN=120

Has this board ever worked?

Ans: No.

If it's brand new, have you checked basics: power supplies; component orientations; current draw; etc?

Ans: Yes MCU & Oscillator placed in correct orientation. and current draw is 6.84 mA ( While not coneting ST-Link USB to PC) and 6 mA ( while connecting ST-Link USB to PC).

You don't have NRST on your debug header; Have you tried adding that, and then connecting under hardware reset?

Ans: Yes I tired MCU NRST(Pull High SCH - test point TD11) Joining directly to ST-Link RST pin and even by MCU NRST (pull low joing -SCH test point TD11 to GND )

[ashishkv29 · Accepted solution]

Solved, Issue was on ST-Link v3 Mini, via connector pin head able to access but not via solder pads.

Thanks.