Template (PCB and interface symbol) to copy for any kind of HAT designs for Raspberry Pi B+. The PCB contains 6 layers with layer display at the lower edge. The assignment of layers is:
- top: signal, polygon connected to GND
- bottom: signal, polygon connected to GND
- layer 1: inner, signal
- layer 2: inner, polygon VCC
- layer 3: inner, polygon GND
- layer 4: inner, signal
Note: geometry tes...