Si5351 things
Cadsoft eagle shematics and board layout for the Si5351A backpack.
Load ATmega32U4 with Arduino bootloader to upload via USB.
Boards avaible at https://oshpark.com/shared_projects/lqFvJlVT
Mounting tips: The LCD is supposed to go on the microcontroller side. mount the large components like SMB connectors, crystal (if hole mounted) and pot on the backside of the board.
Arduino pinout:
D0 ENCODER A (Interrupt)
D1 ENCODER b (Interrupt)
D2 I2C SDA to Si5351A
D3 I2C SCI to Si5351A
D4 Extra
D5 Extra
D6 LCD D7
D7 ENCODER SWITCH (Interrupt)
D8 LCD D6
D9 LCD D5
D10 LCD D4
D11 LCD Enable
D12 LCD RS
D13 External LED
None of the analog pins are connected.