We are currently developing a new product using STM32H723VGT6 (LQFP100 package).
We purchased 10 pieces, and during initial board bring-up, we are observing that several chips from the same lot are unable to communicate via SWD (Device ID read failure) despite proper power supply, clock, and reset configurations.
The issue persists across devices assembled using different methods (SMT reflow vs. manual soldering).
This indicates that the problem is not related to PCB assembly or reflow quality, but potentially to the devices themselves.
I am using the ST-LINK from the Nucleo-H743 board, where the on-board CPU's SWDIO and SWCLK pins have been set to high-impedance (floating) mode to enable external target debugging.
Additionally, we initially attempted to use ST-LINK V2 but were unable to establish any connection, so we abandoned that approach.
We then tested with both ST-LINK V2.1 and ST-LINK V3, and both produced the same results as described above.
15:25:31 : UR connection mode is defined with the HWrst reset mode
15:25:32 : ST-LINK SN : 0054003A3538511133363730
15:25:32 : ST-LINK FW : V3J13M4
15:25:32 : Board : NUCLEO-H743ZI
15:25:32 : Voltage : 3.24V
15:25:32 : Error: No STM32 target found! If your product embeds Debug Authentication, please perform a discovery using Debug Authentication
Product Details:
- Part Number: STM32H723VGT6
- Lot Code: AA178 VQ Z
- Marking: TUN AA D19
- Purchase Quantity: 10 pcs
- Purchase Source:
Issue Summary:
- Out of 10 units, [3] units consistently fail to connect via SWD.
- Power supply, VCAP, VDDA, VREF+, NRST, BOOT0 circuits are correctly implemented.
- ST-LINK V3 and standard connection settings are used.
- Voltage measured at VDD and VDDA is 3.28V.
- NRST line is held at 3.3V.
We suspect that there might be a quality issue with this particular lot.
Could you please provide guidance on how to proceed?
If necessary, we are willing to submit samples for further failure analysis.
