2025-06-29 5:50 AM - last edited on 2025-07-03 7:36 AM by Andrew Neil
Hi , I am also making custom board for GPS, and same issue I am facing, unable to connect via SWD, Please help to debug.
2025-07-02 5:05 AM
Remove the diodes on the debug port, it will work.
2025-07-03 7:19 AM
Removed all 4, but still same issue
2025-07-03 7:33 AM
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
2025-07-03 11:12 AM
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 )