Did I kill my Due?

Other Hardware General Electronics
1

Hello -
After a few hours of tinkering with a fairly complex bit of circuitry (that I'm not going to get into here most likely) I noticed my Due behaving weirdly.

When powering over USB, it connects, the LEDs turn on (as normal), but quickly dim and then turn off. My PC makes the "device disconnected" tone.

There is a slight discoloration under the Programming microUSB port.

When I power up using a bench supply, I draw 700-800mA at 9V - this seems really high to me, but the lights stay on continuously. This power is given via the barrel connector, and the ARM chip seems to heat up fairly quickly when powered on.

Any ideas for what may have broke (and ideally, a repair?) I'd rather not have to source a new Due.

TIA.

2

More than 3.6V or less than -0.3V on any pin will do it (even for a fraction of a second). Something is definitely cooked.

3

You probably fried the processor. However, it's worth checking for other things. Let it cool completely for 5 minutes. Turn it on and start (carefully!) feeling around for hot spots with your fingers. You'd be surprised what you can find out that way.

I assume you disconnected it completely from your mystery circuits.

4

I had let it cool for ~1.5 hours (I stormed away from it once I had convinced myself I had fried it) when I connected it to the bench supply.

The space immediately below the programming port was mildly warm, and the main chip was hot.

5

You are S.O.L. (out of luck).

Maybe if you posted it, we could help you fix your mystery circuit so it doesn't happen to another Due....