Hi all!
This is my first post here, so hello everyone. I am puzzled about one stupid issue I have with my custom STM32F4 board which I recently designed. I am able to program it (SWD) only when... oscilloscope probe is attached to the SWDCLK pin. Probe itself can be attached to the scope, or not, does not matter. Grounding of the probe is also left floating in the air, or may be connected, as you wish. I suspect, that since I am a total beginner, I miss some fundamental theory like, dunno, capacitance of wires connecting ST-Link and my board, or some noise issues, or I don't know what. Little details:
* Command used to upload flash is : st-flash write i2c-test.bin 0x8000000 (Linux).
* Board used as a ST-Link :
http://www.st.com/web/catalog/tools/FM116/SC959/SS1532/PF250863* µC used on my board : STM32F407VET6
* SWDIO connected directly to PA13 and SWDCLK connected to PA14.
Should I post the schematic and/or PCB layout?
Regs.
PS. I thought that oscilloscope probes are designed so they introduce little/no noise into the circuit. I.e. they not interfere with circuit being measured. So why this has happened?