2026-05-21 11:32 AM
Hi all,
Hardware: Custom PCB, STM32H563ZGT6, USB powered.
It was working fine but now gives me :
Error: Cannot connect to access port 1!
If you are trying to connect to a device with TrustZone enabled please try to connect with HotPlug mode. If you are trying to connect to a device which supports Debug Authentication with certificate or password, please open your device using it.
Symptoms:
- MCU gets hot to the touch within ~5–10 s of USB connect; cools instantly on unplug
- VDD measures 3.29 V at the MCU pin
- Chip is still functional: enumerates as STM32 Bootloader in DFU, ST-Link HotPlug connect succeeds, full erase + program + verify works
- "Connect Under Reset" / normal connect frequently fails with Cannot connect to access port 1 or DEV_TARGET_NOT_HALTED
Already tried:
- Full chip erase via HotPlug → heat persists with empty flash
- BOOT0 tied to VCC to force system memory bootloader
Can someone please assist me in resolving this issue?
Thank You.