| 1 | M0 | input (very weak pull-up) | cooperates with M1 to determine the 4 working modes of the module. (Cannot be left floating, can be grounded if not used) |
| 2 | M1 | input (very weak pull-up) | cooperates with M0 to determine the 4 working modes of the module. (Cannot be left floating, can be grounded if not used) |
| 3 | RXD | input | TTL serial input, connect to external TXD output pin; Can be configured as open-drain or pull-up input, see parameter settings for details. |
| 4 | TXD | output | TTL serial output, connect to external RXD input pin;Can be configured as open-drain or push-pull output, see parameter settings for details. |
| 5 | AUX | outputs | Used to indicate the working status of the module; (can be left floating)The user wakes up the external MCU, and outputs a low level during the power-on self-test initialization;It can be configured as open-drain output or push-pull output, see parameter settings for details. |
| 6 | VCC | input | Positive reference of module power supply, voltage range: 2.3~5.5V DC |
| 7 | GND | Input | Module ground wire |
| 8 | Fixing |
| holes Fixing holes |
| 9 | Fixing |
| hole Fixing hole |
| 10 | Fixing |
| hole Fixing hole |
|
|
|
|