I designed and printed two PCBs featuring the STM32H743 microcontroller. I initially worked with the first PCB without any issues, but it suddenly stopped functioning, and the chip was no longer recognized. After numerous unsuccessful attempts to resolve the problem, I decided to switch to the second PCB.
On the second PCB, everything worked perfectly with the same code, until I changed the clock frequency from 64MHz to 200MHz. After this change, the microcontroller stopped being recognized, presenting the same issue as the first PCB. I reverted the clock frequency back to 64MHz, but the STM32 still wasn’t detected.
I'm using an ST-Link V2 for debugging. STM32CubeIDE detects the ST-Link but never the chip itself. I’ve measured all the relevant voltages on the microcontroller, and everything appears to be within the correct ranges. I’ve also tried using a different ST-Link, but it didn’t help. Additionally, I downloaded STM32CubeProgrammer, but it too fails to detect the chip.
I attempted to connect under a hardware reset by grounding the NRST pin, but that didn’t work either. I even updated STM32CubeIDE, but the problem persists.
I’ve tried numerous troubleshooting steps, but the chip remains unrecognized. Given that all voltages on the PCB are correct, I’m at a loss as to what could be causing this issue. I’m hesitant to solder another PCB, fearing the same problem will occur again.
