+------------------------------------------------------------------------+
|  ESP32-DevKitC-V4  ---  bl0906-mainmeter                               |
+------------------------------------------------------------------------+
|  Rails: 5V, 3V3, GND                                                   |
|                                                                        |
|  em6  [BL0906 6-channel AC energy meter (UART, 19200 baud)]  -- Mains  |
|    VCC   -> rail 3V3                                                   |
|    GND   -> rail GND                                                   |
|    TX    -> em6_uart (GPIO16)                                          |
|    RX    -> em6_uart (GPIO17)                                          |
|                                                                        |
|  Passives:                                                             |
|    c1: 100nF capacitor, em6.VCC  <->  GND   (decoupling bl0906)        |
|                                                                        |
|  BOM:                                                                  |
|    - ESP32-DevKitC-V4                                                  |
|    - BL0906 6-channel AC energy meter (UART, 19200 baud)  (em6)        |
|    - 1x 100nF capacitor                                                |
|                                                                        |
|  Power: ~8mA typical, ~20mA peak (budget 500mA)  OK                    |
|                                                                        |
|  Warnings: none                                                        |
+------------------------------------------------------------------------+