Hey guys, what I am trying to achieve is to build a display using 52 RGB-LEDs, controlled by an ATMEGA32U4. I would also like to be able to use the Arduino-IDE, so I flashed the Leonardo bootloader (Caterina-Leonardo) onto it. The schematic of the microcontroller can be seen here: Keep in mind that some caps between +5V and GND as well as a cap between VBUS and GND are not shown on the image but are on the board. The board itself is manufactured and 100% tested. I also tested all of the connections of the microcontroller with my multimeter, and everything seems to be ok.
So the problem is, if I connect it to my PC, it isn't recognized as an USB-Device, or recognized at all. I then measured the D+ and D- lines of the microcontroller, but their signal doesn't seem right (at least it doesn't look like it should, some digital signal):
I can flash the microcontroller, and when I set CKOUT then I can also measure the clock on PIN7, so at least not everything seems to be wrong.. Here are the Fuses I tried, as I found them on another project that was successfully using the ATMEGA32U4:
The output of a test program that just sets some Pins to HIGH is the following: So obviously there really is something wrong..
Any ideas what might cause this? Are the fuses ok? Is there something else I could test or measure when I am back in the lab tomorrow?