NUCLEO-F207ZG: overcurrent LD7 permanently on; also COM (red) & LD5 (Green).

[Will1]

Before starting the blinking program, when I plugged in my PC USB to micro the user LED's (1-3) could be toggled when I hit the blue push button, now they can't.

 

Within Kiel, I started a new project LED blink. I found my MCU (as seen in the image), then within the manage run time the only option was the MCB board, in which I thought it was okay to proceed. using the LED API, I wrote this code, set the target compiler as well as the download settings, then compiled and flashed the board. I then hit reset and that's when the over current led turned on, and has stayed on even when I unplug and plug the micro cable back into the board.

 

On start-up, these are the LED's that I see, at the top is LD7, the green is LD6(power) and the bottom is LD4 (COM).

So, what I think is happening is that the highlighted component which is a power safety switch has a fault output, that is an open drain, so when a fault condition is occurring it pulls that line to GND, which is why I see LD7. That switch will remain off until it see's a valid voltage.

 

If anyone could help that would be great!

[Will1]

Well for anyone curious I contacted ST in which they suggested an ESD fault most likely happened

[Alex R]

Hi,

Note that the overcurrent indicator is only for the USB OTG port (CN13) which is an output port.

Did you try to power your board by injecting power on the CN13?

Is it possible that your code is configuring the USB_GPIO_IN pin (PG7) as output and being driven LOW. That would turn on the LD7 too.

Have you tried to single step through your code?

[Piranha]

Full erase would be the first and simplest thing to try.

[Will1]

Hi guys,

I did not try to power the board via CN13, and I am quite confident the pin was not reconfigured. I stepped through the circuit using the schematic checking voltages and it is indeed the power switch U12 that has tripped due to an over current. I am just trying to figure out how to reset that switch.

I am powering the board via CN1, and currently have CN13 plugged in from my laptop as well (&JP4 is "on"), I was hoping that when the switch saw an appropriate voltage it would reset, but that's not the case.

ANY IDEA's?