I made my own diy "bare bones" Arduino Due in an embedded application. Basically I was making a portable Bluetooth headphone amplifier for a school project. The point of the MCU was to display battery information on a touchscreen LCD and to control volume with a digital resistor. Everything else on my board seems to work including Bluetooth. Since this was a prototype, I added a switch which would bypass the digital resistor and go to a normal pot for volume control, so I know everything on my board works except the SAM3x8E.
Here is the issue:
When I plug in the USB, the device does not get recognized by the PC at all. No COM ports are available in device manager. If I press the reset button, the chip gets abnormally hot. Uncomfortably hot to the touch! If you unplug power and plug it back in, even after waiting a second or two, it STILL starts getting hot. It's only after you power cycle and hit the ERASE button a few times that the chip finally stops overheating. Also, during this process, my 3v regulator drops out as if the chip is drawing too much current. (because the blue 3.3v led goes out)
After the power cycle, things go back to normal, and Bluetooth and the rest of my amplifier works fine. Can anyone take a look at my schematic and see if anything obvious is wrong? I am a little lost, any suggestions to help diagnose this issue?
Tomorrow, I will hook it up to an oscilloscope to make sure my crystals are providing clock. Any other test I can perform? I have triple checked this schematic against a number of Arduino Due and SAM3x8E reference schematics and do not see anything obviously wrong.
Here are the Eagle Cad Files:
Also some photos:
Here is the actual board (don't mind the unsightly makeshift jumpers):
Also, here is a schematic of the Power circuit: