I have a custom build of an arduino mega (i.e. I took the reference design, and modified it to fit my specific requirements). As a result, the layout is substantially different from the reference circuit.
Would appreciate thoughts on the ceramic resonator layout. From what I've read, the frequencies this thing runs at (8MHz) are such that it doesn't really matter, but I'd appreciate input nonetheless:
- C16 is a bypass cap
- R12 is the resistor required for the resonator (is its placement correct? Should it be behind the ceramic resonator, or where it is?)
- RN1 is a 10K resistor network used for I2C, and the reset line.
- D4 is part of the atmega reset circuit
- There are no signal lines underneath the resonator, just the ground plane.
- This is a 2 layer board, ground fill on both sides.
- The resonator is http://www.digikey.com/product-detail/en/0/490-5994-1-ND