The commonly used interfaces of wireless modules are generally USB, UART and SPI, TTL, RS232, RS485. When we specifically explain these interfaces, let's first understand the specific role of the wireless module interface. The wireless module interface is used for communication between the module and different devices. For example, we want to modify the communication protocol of the module or the communication channel of the module, and then we can complete it through these interfaces.
The above six interfaces are further divided into two types of different types of interfaces. USB, UART, and SPI are physical interfaces (hardware), while TTL and RS232.RS484 are level standard (electrical signals) interfaces.
The USB interface is a familiar interface mode. It is a universal serial bus. It is a serial bus standard for communication between a wireless module and a computer system. Its advantage is that it is easy to use and plug and play.
The UART interface is a serial data bus. It belongs to the asynchronous serial port. The bus can communicate in two directions. The hardware consists of two cables for transmitting and receiving.
The SPI interface is a synchronous serial peripheral interface bus. The working mode is master-slave mode. It is a master device to control multiple slave devices. The advantage is that the signal line is small, the communication protocol is simple, and the data rate is high.
The TTL interface is an interface for transmitting data in parallel. Its advantage is that the TTL data signal outputted by the main control chip of the wireless module is directly transmitted to the input interface through the cable. The disadvantage is that the circuit has poor anti-interference ability and is prone to electromagnetic interference.
RS232 interface is a standard interface for asynchronous transmission. It has two forms of DB-9 (nine pins) and DB-25 (25 pins). Computers usually have these two interfaces. We usually call these two interfaces. Interfaces are COM1 and COM2
RS485 is a standard for electrical characteristics that defines drivers and receivers in a balanced digital multipoint system.