X8j6l Schematic -

The schematic identifies specific integrated circuits (labeled with "PU" or "U" prefixes) that manage voltage regulation.

The main clock source (Y1) is a 16 MHz crystal. The load capacitors (C20, C21) are sized at 20pF, but intriguingly, the schematic includes pads for parallel resistors (R45, R46) that are unpopulated. This is a classic "debug provision," allowing engineers to modify the drive level of the crystal if startup issues occur. x8j6l schematic