Code does not execute until ST board manually reset.

[KMale.1]

I wrote a simple LED blink program using STM32F767zi board. It works properly when I use STLink debugger. but the problem is when I remove the STLink and connect the board directly to an external power source, the code does not execute until I manually reset the ST board. The program does not have any errors. I checked the input voltage and it shows 7.5V. Could someone please tell me what is the reason for this issue?

Thank you.

[waclawek.jan]

How is BOOT0 pin connected?

JW

[KMale.1]

Thank you for the reply. I grounded boot0 pin using 10k resistor because many people suggested that in the internet. But it did not work. I found a solution. I previously used external oscillator (Christal resonator)​ to initiate my peripheral clocks. But I changed it to internal oscillator and it worked. Again I changed HSI to HSE and then again didn't worked. I don't know how external resonator affects the execution. Can anyone explain this? Is it implies that external resonator cannot use for the general purposes? Is there any special way to use external resonator?

Thank you.​

[Uwe Bonnes]

There are application notes around crystal oscillators on the ST website. Read them, look at the schematics of the demo baords and compare with what you did. Single step through the code setting up HSE and find out where is fails or decipher the RCC registers when it does not "work". How do you even judge that is "didn't worked"

[KMale.1]

Thank you for the reply. I'll read the application notes. "Didn't work" means always I had to manually reset the​ ST board to blink the LED when using the HSE oscillator.

[waclawek.jan]

Check all VDD and ground connections, including (or mostly) the analog ones. Measure directly on the physical pins.

Review blocking capacitor placement and power supply.

Try setting BOR, if you haven't set it before, or change its settings.

Also try your code on a "known good" board such as Nucleo or Disco.

JW