Hi
I am facing an issue while trying to connect to an STM32U5G7VJT6 using ST-LINK.
Target no device found
Error in initializing ST-LINK device.
Reason: No device found on target.
Hardware Details-
MCU: STM32U5G7VJT6
Debug Interface: SWD
SWDIO: PA13
SWCLK: PA14
Target Voltage: ~3.3V
BOOT0: Connected to GND
VCAP capacitor fitted (4.7 µF)
NRST connected to debugger header
Debug Connector-
The attached schematic shows the SWD/JTAG programming header connections.
Troubleshooting Already Performed-
Verified SWDIO (PA13) and SWCLK (PA14) continuity.
Verified target supply voltage is present.
Tried STM32CubeProgrammer with:
Normal mode
Under Reset mode
Hot Plug mode
Tried different reset modes (Software reset, Hardware reset, Core reset).
Reduced SWD frequency down to low values (100 kHz and below).
Updated ST-LINK firmware.
Referred to multiple ST Community posts with similar symptoms and tested suggested solutions.
Confirmed BOOT0 is low.(I did try high also)
Question
In this condition, is it possible that the STM32U5G7VJT6 has entered a state where the SWD interface is no longer accessible (device appears "locked" or unresponsive to the debugger)?
Can any firmware configuration, option bytes, low-power mode, clock configuration, or watchdog condition cause the device to stop responding to ST-LINK completely?
If the MCU is locked or stuck in such a state, what is the recommended recovery procedure?
Hardware reset sequence?
BOOT0 bootloader recovery?
Connect Under Reset mode?
STM32CubeProgrammer mass erase?
Any other recovery method specific to the STM32U5 series?
Is there any method to determine whether this is a hardware issue (power, reset, VCAP, PCB, soldering, etc.) or a software/firmware issue that has made the device inaccessible?
Any suggestions for diagnosing or recovering the MCU would be greatly appreciated.
THANKS
