Research And Implementation Of SD Cards And Embedded USB Host-based Data Logger

As an important data recording instrument, Digital data recorder has been appliedin various kinds of industrial fields．It has many kind of interface to receive data. Whenthe instrument was scattered, the data was transferred via Serial Port (COM) or ParallelPort (EPP). If the instrument was centralized, RS485,CAN,Ethernet，or other kind oflocal bus was used. With the progress of computer technology, USB was widely used.USB has many advantages, such as more fast, good compatibility, support plug andplay，easy to use。Using USB to transfer data will greatly enhance the functionality andperformance of the recorder.The main purpose of this design was developing a storage module which supportdata record in USB Flash disk or SD card and a communication module which supportvaries kind of communication interface. The USB device used in this design can be usedas USB host, so it can support varies kind of device. In this design it only support USBMass Storage device, it can also support USB-HID device such as keyboard, mouse,printer and other device after adding proper software. The communication modulesupport communication with RS232, RS485, and RS422. And this module cancommunicate with varies kind of device via adapting module. This starts with theprogress of data recorder, the communication technology and advantages of using USBas communication interface in comparison with other bus classes．Then discuss thehardware and software developing and knowledge used in this design．For displaying onthe PC side, we choose to implement the file system for the data storing structure on SDcard, generally FAT file system is commonly used in SD card data storage, in order tosupport windows operating system, while for Linux we can also install software tosupport the FAT file system. After storing the data, this design uses LCD to thefunctionality of the system and to provide users with a control interface, LCD isconnected to the MCU with the SPI interface for no consider of communication speedand also saving microcontroller pins. We also introduce a method which MCU can use itperipheral communication with the computer on the USB interface. This is a methods toimplement data communication with MCU and PC, we also described the circuit connection of the microcontroller and SD card, the system design and softwareprocesses chart and achieved a typical data acquisition...