Can't start MCU on Nucleo-H563ZI when powering through E5V

[continuum]

I have Nucleo-H563ZI board and I'm trying to power it through external 5V source (E5V). When I connect the 5V power source and set PWR SEL jumper (JP2) to E5V, I can see the power LED (LD5) light up and even the ethernet controller seems to be active. But the firmware on MCU does not seem to start until I power on the on-board ST-Link through USB. After that, I can disconnect the USB and it still works.

[Foued_KH]

Hello @continuum , 

Please try measuring the voltage and current at the input of the Nucleo-H563ZI board using a multimeter to see if it matches the specifications.

Check also, 

Foued

[continuum]

I checked the voltage at E5V pin and at the PWR SEL jumper, both measure stable 5.04 V. The voltage at JP4 and JP5 measure 3.3 V.

I wrote a simple program that toggles two LED (LD1 and LD2 on board) alternately. When I connect E5V, the current at the input is ~67mA but no LED is switched on. After connecting STLink through USB port, the current at E5V jumps to ~92mA and the LEDs start switching. After disconnecting STLink, the current goes down to ~65mA, the LEDs stop switching but the last switched LED stays on so it definitely is powered using E5V input. 

[Bob S]

See if there is a solder jumper on the NRST signal between the on-board STLink and the CPU.  On some of the Nucelo-144 boards (F429 and F746) I had to remove that zero ohm resistor (SB111) in order for the CPU to run when powered from the USB port (with a USB wall power supply, not a real PC USB port).  That may also be the case for E5V power.

[ONadr.1 · Accepted solution]

For Nucleo boards, the MCO from the debugger is used as the clock source for main MCu. Try to configure the MCu for an internal oscillator or place a crystal and auxiliary capacitors to the MCu and select the External Crystal as the clock source. The problem can also be a slow start of the clock and then the program jumps into some error routine, that also needs to be treated.

[continuum]

You are right, after configuring MCu to use the internal oscillator (HSI), the program started to work without needing to power on the on-board debugger. 

I was a little bit confused as the crystal (X3) and the capacitors (C69 and C70) are already placed on the board so I assumed the default CubeMX configuration would use them. Studying the user manual I realized that's not the case.

After switching SB49 Off, SB3 On, SB4 On and selecting Crystal/Ceramic Resonator as HSE source I was able to use the on-board 25MHz resonator. 

[Piranha]

https://community.st.com/t5/boards-and-hardware-tools-mcus/stm32f767zi-on-external-power-supply-is-stuck-until-reset-button/m-p/115194