Problems with Custom Board - Target not answering

[syso2342]

Hello,

I have made a custom board based on the MK20DX256, as an alternative to the teensy for one of my projects.
Instead of the MINI54TAN, I am using the SWD-Interface of the MK20 to program it. I can verify that my programmer works just fine.

The circuit is based on the Teensy 3.1 Schematic. The inductor is a 10uH.

Can someone check for errors on the schematic, too? I checked it now multiple times and find no issues.
The crystal used in the circuit is 16MHz 20pF:

http://www.mouser.de/ProductDetail/...GAEpiMZZMsBj6bBr9Q9aQ6SZfIlWoiS4s1%2bSpYOVXo=

 

[arturolaz]

Check this thread, it might be helpful http://forum.pjrc.com/threads/27023-DIY-Teensy-woes

 

[PaulStoffregen]

You might need to edit the Teensyduino startup code, to increase the capacitance. Or add 2 real capacitors, if you want to run the code without mods. Teensy uses an 8pF rated crystal.

Of course, there could be other problems. Usually a crystal will at least oscillate with the wrong capacitance.

 

[syso2342]

What I only see for now as a difference: I don't have any connection to VBAT.
Is the connection to VBAT from VDD really required?

 

[syso2342]

What I only see for now as a difference: I don't have any connection to VBAT.
Is the connection to VBAT from VDD really required?

Things verified so far:
- VDD/AVDD is stable and at 3V3 (checked with oscilloscope)
- All components are correctly soldered
- No bridges on pins are present
- Target answers now (SWD), but doesn't blink LEDs after flashing it with teensyduino blink example.
- Verified Anode and Cathode of LEDs.