+5V --+---+------+          +----------+
         |   |      |  BAT54C  |          |
         |   |     ---        ---         |
         X   X     \ /        \ /         | ++
      1K X   X    '---,      '---,      -----
         X   X 1K   |          |         ===   3.6V
         |   |      +-----0----+        -----  Li Cell
         |   |            |8             ===
         |   |     +------------+         |
         |   |   6 |   VDD      | 3       |
 SCL-----o---------|SCL     -INT|---      |
             |   5 |            | 7       |
 SDA---------o-----|SDA     -OUT|---      |
                 1 |            |         |
    +--)|-----o----|OSC1        |         |
    |  18pf   |    |            |         |
    |        ---   |            |         |
    |  32768 [ ]   |  PCF8563   |         |
    |    Hz  ---   |    RTC     |         |
    |         |  2 |            | 4       |
    o--)|-----o----|OSC2     GND|---------o
    |  22pf        |            |         |
    |              +------------+         |
    |                                     |
  -----                                 -----
   ---                                   ---
    -                                     -