Interface and test of uart rf module

By sdga:NiceRF Wireless Technology Co., Ltd

The uart rf module module can be known from its name as a module for data transmission. The form of transmission can be one-to-one, one-to-many, or other forms. In addition to the difference in the transmission form, the interfaces of the uart rf modules are also different. The common interfaces are TTL type, 485 type or 232 type, USB type and so on. These interfaces are briefly introduced below.

TTL type of uart rf module

It means that the interface level of the uart rf module is TTL level. TTL level signal stipulates that +5V is equivalent to logic "1", and 0V is equivalent to logic "0" (when binary is used to represent data). This data communication and level regulation method is called TTL (transistor-transistor logic level) signal system. This is a standard technology for communication between various parts of a device controlled by a computer processor. Generally speaking, the TTL interface supports full-duplex communication.

232 type of uart rf module

It means that the interface of the uart rf module is 232 level. 232 interface, which conforms to the serial data communication interface standard formulated by the Electronic Industries Alliance (EIA), the original number is EIA-RS-232232,). RS232 is the serial communication interface standard issued by the Electronic Industries Association of America in 1962 , RS stands for Recomend Standard, the recommended standard, and 232 is the marking number. The standard specifies the physical interface and logic level of serial communication. The simplest RS232 communication consists of three data lines, namely TxD, RxD and GND. RS232 adopts negative logic level, that is, -15V~-3V represents logic "1", and +3V~+15V represents logic "0". The level here is the voltage of the TxD line (or RxD line) relative to GND. Generally speaking, the 232 interface supports full-duplex communication.

485 type of uart rf module

It means that the interface of the uart rf module is 485 level. Unlike RS-422, RS-485 and RS-232, the data signal adopts a differential transmission method, also called balanced transmission. It uses a pair of twisted pairs, one of which is defined as A and the other is defined as B. Normally, the positive level between the sending driver A and B is +2~+6V, which is a logic state, and the negative level is -2V~6V, which is another logic state. There is another signal ground C, and there is an ‘’enable’’ terminal in RS-485, which is available or not in RS-422. The ‘’enable’’ terminal is used to control the disconnection and connection of the sending driver and the transmission line. When the ``enable'' terminal works, the transmitting driver is in a high-impedance state, called the ``third state'', that is, it is the third state that is different from the logic ``1'' and ``0''. state. Since RS485 is differential communication, receiving data and sending data cannot be carried out at the same time, that is, the general 485 interface only supports half-duplex communication.

USB type of uart rf module

It means that the interface of the uart rf module is USB. USB is an external bus standard that regulates the connection and communication between computers and external devices. The USB interface has a hot swap function. The USB interface can be connected to a variety of peripherals, such as a mouse and keyboard. USB was launched in 1996 by Intel and other companies jointly at the end of 1994. It has successfully replaced serial and parallel ports, and has become a necessary interface for today's computers and a large number of smart devices. The USB version has undergone years of development, and has now developed into version 3.0. USB is a commonly used pc interface, it has only 4 wires, two power and two signals, so the signal is transmitted serially. The usb interface is also called a serial port, and the speed of usb2.0 can reach 480Mbps. It can meet various industrial and civil needs. Use two uart rf modules to perform a simple communication test, as shown in the figure below.