STM32H757 - Start up issue and sync

[yuri CH]

I am working with the STM32H757 on a custom board.

The M7 runs with FreeRTOS, the M4 is bare metal. 

Both cores have output GPIOs connecteed to LEDs which allow me to make sure that both of the cores are up and running.

At the begining of the code for each core there is a default code which is responsible for the boot mode sequence, this code i have left untouched as it was generated by the cubeMX.

When i run my project under debug with ST-LINK everything is ok, both cores start and run correctly, when i remove the debugger and power up i see that the M4 is running but the M7 is not.

i have tried adding some delays during the process but it was inefficient in solving the problem.

Please help me understand what am i doing wrong and what is the diference between running with debugger and without...

thanks in advance :)

[TDK]

The debugger explicitly sets the start address. You can attach the debugger after starting to see where the code is. Likely it is running but busy somewhere. Verify option byes have M7 code booting from correct flash address.