As I am using the STM32H745 board when I attach my external board to the controller the LED2 of the controller starts blinking. As datasheet refer LED2 to STLK Over Current. now my LCD is not working nor is it debugging. but LED2 and LED3 are still blinking red.
It seems the current on your board exceed the capability of STlink power, so you can add another power on other port and select board power from this port. or you can remove some external peripheral or daughter boards on the main board.
