The Designed Of ARM7-based Digital Audio Reception, Decompression And Play Unit

At present, many digital communication are still connected by cable,But the world is moving into the digital Information Age.Therefore, the cable connecting of digital devices brought a lot of inconvenience to people who want to communicate with information network anytime, anywhere. Get rid of the shackles of a wired connection and the development of wireless connection technology, have become a trend.The need especially for short-range wireless data and voice communications technology increasingly urgent. Now common short-range wireless communication technology are infrared, wireless LAN, HomeRF and Bluetooth technology. Of which Bluetooth technology is rapidly improving and growing , Development prospects well in the field of wireless transmission.Bluetooth technology supports data transmission and voice transmission,and can be achieved communicating between the related equipment.Basically, the previous wireless audio transmission is used to simulate transmission scheme, which is easy to receive outside interference, poor stability, greater distortion. Therefore, it emerged digital audio technology, which is the combined both digital integrated circuits and communications technology with the development. In order to ensure better sound quality, digital audio technology basically uses forward error correction coding and decoding technology to process the audio signal, so to correct a lot of unexpected error. Wireless transmission of audio signal there was a new way.While the rapid development of wireless communications technology, digital audio technology is developing rapidly, in digital audio technology has a wide range in our social life. The research in the field of digital audio also has a very bright future. The advanced Bluetooth technology and integrated digital audio technology, can achieve a low-cost wireless digital audio transmission, decoding and playback of digital products for the whole. Such products are a promising market, not only can construct high-quality wireless audio and video products, but also in the classroom teaching, the importance of the meeting has been widely used. Bluetooth technology to a variety of data and voice equipment through the most convenient way to achieve interoperability at close range, the composition of the network, anytime, anywhere people can easily connect to the network, fast and flexible data and voice communications. Bluetooth technology allows people to enjoy a more convenient application of new technologies but also.The functional requirements of the whole system design is in clear,the overall structure of the design elements is presented in chapter II。And the options available were compared, select the most appropriate solution. In this design,LPC2148 is the processor, using Bluetooth serial port Bluetooth wireless core module HC-04, extract the digital audio playback module VS1003, SD card storage module. Software part of embedded real-time operating system configurationμC/OS-Ⅱ.The designed of ARM7-based digital audio reception, decompression and play unit is accomplished in three steps: hardware design, software design and PCB system board and the circuit board debugging.Hardware design includes a. the minimum system of LPC2148 processor, the power modules, the clock module, the reset the module and the download debugging module. LPC2148 as the core of the entire unit complete a variety of data processing and exchange work. Bluetooth module from the data and the data from the SD card will be processed here and then sent, along with the input / output modules for data interaction. 2. Wireless Bluetooth module, it will be received from the other Bluetooth device interface to the data sent to the processor through the serial port, in turn processor to send data to another user. 3. Digital audio decompression, playback module, Bluetooth module receives the audio data or audio data stored in SD extract the broadcast and playback. Which use the hardware decompression decompression, using the audio codec chip is VS1003. 4. SD Card is a data storage module, used to store the data coming from the Bluetooth receiver, you can also store digital audio recording of the audio data processing unit. Processor through the SPI interface, a bit of these audio data streams sent to the VS1003 chip. 5. Input and output modules, including the key signal input, as well as LCD interface design.Software design, including embedded real time operating systemμC/OS-Ⅱ, detail of the transplant processμC/OS-Ⅱ. The design of the application provides a system platform. Write drivers for each module, including the serial driver, SPI port drivers, LCD drivers, including basic initialization function, the register read and write functions, send and receive functions, etc.PCB system board and the circuit board debugging, detailing some common rules and some issues which should be concerned at the process of PCB system board of, including setting the rules, the choice of line width, wiring layer settings, alignment rules. When hardware design of the power module and the smallest system was tested both in the right circumstances, we can follow-up of the software design.The ultimate realization of a wireless audio processor, the wireless Bluetooth transmission module to receive digital audio data from other devices, which is processed by the processor to the bit stream which can be sent to the audio decoder, vs1003 can play high-quality stereo. The audio data received by the Bluetooth can be stored to the SD card. The eventual realization of a wireless digital audio receiver, decompression, playback function .