Pins and connections: A0: 7SD 10 (digit 2) A1: 7SD 7 (digit 1) A2: 7SD 11 (digit 3) A3: 7SD 1 (digit 4) A4: RTC SDA A5: RTC SCL A7: Squelch button (analog-only pin; requires external pull-up) A6: Set, move down (to past) (analog-only pin; requires external pull-up) D2: 7SD 8 (top) D3: 7SD 9 (upper-left) D4: 7SD 12 (upper-right) D5: Set, move up (to future) D6: 7SD 2 (middle) D7: 7SD 3 (lower-right) D8: 7SD 4 (dot) D9: 7SD 5 (bottom) D10: 7SD 6 (lower-left) D11: PWM LED MOSFETs D12: Enable "set alarm" (otherwise "set clock") D13: Alarm on/off Digits display, numbered clockwise from bottom-right Digit x => 5V on pin y Digit 1: Pin 7 (A1) Digit 2: Pin 10 (A0) Digit 3: Pin 11 (A2) Digit 4: Pin 1 (A3) GND at: 2 M (D6) 3 BR (D7) 4 dot (D8) 5 B (D9) 6 BL (D10) 8 T (D2) 9 TL (D3) 12 TR (D4)