Design scheme of wireless communication terminal system based on USB/RS232

“This article introduces in detail a wireless data communication terminal system designed with a USB communication interface. This system uses the high-speed, reliable and online programmable STM32F103C6T6 as the main control device to realize the wireless transmission of data and files between the computer and other terminals. Experiments have proved that the design of the system has the advantages of low cost, high integration and simple design, and realizes wireless networking and networking functions. It is suitable for remote download and upload of files of portable Electronic devices, such as wireless cutting machines and various objects. The data transmission of networked handheld terminals and other devices provides a solution.

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Introduction: This article introduces in detail a wireless data communication terminal system designed with a USB communication interface. This system uses the high-speed, reliable and online programmable STM32F103C6T6 as the main control device to realize the wireless transmission of data and files between the computer and other terminals. Experiments have proved that the design of the system has the advantages of low cost, high integration and simple design, and realizes wireless networking and networking functions. It is suitable for remote download and upload of files of portable electronic devices, such as wireless cutting machines and various objects. The data transmission of networked handheld terminals and other devices provides a solution.

1 Introduction

At present, most instruments and equipment use RS232 interface to communicate with computers, but with the development of computer technology, the USB standard interface that supports hot plugging will replace the RS232 interface, so computers will be less and less equipped with or even not equipped with RS232 interfaces.

Although both RS232 interface and USB interface are serial interfaces, their data format, communication protocol, signal level, and mechanical connection mode are different. In this way, the computer cannot control the existing equipment. To solve this problem, the RS232 interface of the existing equipment must be converted to a USB interface. To realize this conversion, USB/RS232 bridge devices such as CP2102 and CP2103 can be used to design. The computer virtualizes an RS232 interface through the USB interface and connects with the traditional equipment. The device-to-computer interface is in the form of a USB interface.

2. Interface design of wireless data communication terminal system

The wireless data communication terminal system system includes: CP2102USB to RS232 module, STM32F103C6T6 control module, NRF2401+ wireless sending module. The structure diagram is shown in Figure 1:

3. Selection of wireless data communication terminal system

The USB interface and RS232 interface converter CP2102/CP2103 launched by Silicon Laboratories is a highly integrated USB-UART bridge that provides a simple and convenient solution to convert RS232 to USB using minimal components and PCB space. As shown in Figure 2, CP2102/CP2103 includes a USB function controller, USB transceiver, oscillator, and asynchronous serial data bus (UART) with all modem control signals, in a 5×5mm MLP-28 package.

P2102/CP2103 is a USB/RS232 bidirectional converter. On the one hand, it can receive USB data from the host and convert it to RS232 information stream format and send it to the peripheral; on the other hand, it can convert the data received from the RS232 peripheral to the USB data format and send it to Host, which includes control and handshake signals.

UART is set by programming, supporting various data formats and baud rates. Program the data format and baud rate of the UART on the COM port of the PC. Table 1 is its data format and baud rate.

The NRF24L01+ module wireless data transceiver module uses Nordic’s nRF24L01+ high-performance wireless radio frequency chip to perform wireless data transmission in the 2.4GHz wireless frequency band, ensuring high-speed communication quality, and can implement a strict data verification mechanism on the wireless communication protocol. Ensure reliable communication of data. The NRF24L01+ module can configure the local address and sending address. You can select the channel (0-127) to set the frequency and realize the data transmission of multiple electronic systems, which can realize the wireless data transmission between the device and the device. Convenient and simple.

4. Hardware design of wireless data communication terminal system

The peripheral design of CP2102 is shown in Figure 3, and the main controller circuit is shown in Figure 4.

5. Wireless data communication terminal system debugging

The PC-side software design interface is shown in Figure 5

6. Concluding remarks

This solution uses USB to UART technology, combined with wireless technology, provides a simple and practical design solution for data communication between PC and remote equipment, reduces development time, reduces development costs, simplifies peripheral ports, and provides peripherals The 5V power supply can be used for data transmission and signal control; it also provides a convenient and cheap method for the development and learning of data wireless application systems.