| Pin | Function | Explain |
| 1 | VCC | Power supply <1.8-3 |
| 2 | PWM1 | Support UART, IIC, APP control |
| 3 | PWM2 | Support UART, IIC, APP control |
| 4 | 104 | High and low levels can be controlled by APP |
| 5 | NULL | |
| 6 | STAT | UART communication mode: unconnected low level, high level aft er connection.
IIC communication mode: no connection to high level, connection, disconnection or reception will be interrupted by "interrupt" work, interrupt down edge hold time 200ms |
| 7 | NULL | |
| 8 | NULL | |
| 9 | 101 | High and low levels can be controlled by APP |
| 10 | 102 | High and low levels can be controlled by APP |
| 11 | NULL | |
| 12 | MILL | |
| 13 | 103 | High and low levels can be controlled by APP |
| 14 | PWH3 | Support UART, IIC, APP control |
| 15 | TO4 | Support UART, IIC, APP control |
| 16 | MILL | |
| 17 | ALKD | Broadcast scintillation, frequent connection after connection (master and slave effectiveness) |
| 18 | RTCA | RTC timing time produces the falling edge interrupt signal, normally high level. |
19 |
TXD_0R_DD | SELECT boot for high power, this pin function is serial TXD.
SELECT boot for low power, this pin function is IIC DD |
| 20 | RXD_0R_DC | SELECT boot for high power, this pin function is serial RXD.
SELECT boot for low power, this pin function is IIC DC |
| 21 | SELECT | UART or IIC selection pin
Open low level: IIC communication mode
Open high level: UART communication mode
The default SELECT is suspended to high level: UART communication mode. When the user needs IIC, the SELECT pin should be grounded. |
| 22 | PWRC | Down wake-up, when the AT command needs to be sent in the connection state, the AT instruction mode can be expressed by keeing this pin low level, and the pin is AT instruction mode at high and low levels in the unconnected state. |
| 23 | RESET | Hardware reset pin |
| 24 | GND | Power supply |
