+5V                3.3V                3.3V                3.3V               ST-Link
             ^                  ^                   ^                   ^       o       o       o       o 3.3V
     47u     |         100n     |                   |          100n     |       |  N    |  S    |
   +----||---+        +----||---|                   |         +----||---+       |  R    |  W    |
   |         |        |         |                  +-+        |         |       |  S    |  I    |
   |         |       ---        |             2,2k | |       ---        |       |  T    |  M    |
  --         |                  |                  | |   +--------------|-------+       |      ---
             |                  |                  +-+   |              |               |
+--------+   |       +---------------------+        |    |  +------------------------------------------------------------+
| U  +5V | --+       |          16         | TxD    |    |  |           9               18                               |
| S   D+ | ----------|  6                2 |--------|----|--| 3 RxD    Vdd             PD1                               |
| B   D- | ----------|  5    CH340G        | RxD    |    |  |                                                            |
|    GND | --+       |                   3 |--------|----|--| 2 TxD                                                PA1 5 |---+
+--------+   |   +---|  4                  |  100n  |    |  |                       STM8 S103F3P6                        |   |
             |   |   |                  13 |---||---+----+--| 4 NRST                                                     |   |
             |   |   |    7       8        | DTR    |       |                                                            |   |
             |   |   +---------------------+        |       | GND VCAP  PA3  PB4  PB5  PC3  PC4  PC5  PC6  PC7  PD3  PD4 |   |
             |   | 100n   |       |    |            |       |  7   8    10   12   11   13   14   15   16   17   20    1  |   |
             |  ===       +--|#|--+    |          \         +------------------------------------------------------------+   |
             |   |        |       |    |           \           |   |     |    |    |    |    |    |    |    |    |    |      |
             |   |        | 12MHz |    |            |          |   | 1u  |    |    |    |    |    |    |    |    |    |      |
             |   |       ===     ===   |            |          |  ===    |    |    |    |    |    |    |    |    |    |      |
             |   |        |       |    |            |          |   |     |    |    |    |    |    |    |    |    |    |      |
            --- ---      ---     ---  ---          ---        --- ---    |    |    |    |    |    |    |    |    |    |      |
                                                                         o    o    o    o    o    o    o    o    o    o      o
                  +----------+                                          io0  io1  io2  io3  io4  io5  io6  io7  io8  io9   Autorun
                  | AMS 1117 |
     5V o----+----|   3.3    |----+----> 3.3V
             |    +----------+    |
             |                    |
            ===                  ===
             |                    |
            ---                  ---