Design Of Bluetooth Audio Application System Based On μC/OS-ii Embedded System

This paper puts forward a Bluetooth audio application system based on μC/OS-II RTOS, thehardware and software solutions of this system are also given. Compared with embedded Linux,μC/OS-II is more compact and efficient, which can effectively reduce the hardware cost andcomplexity of hardware circuit, improve the reliability and market competitiveness.We introduces the software and hardware design scheme of this Bluetooth audio system. Inhardware aspect, we adopt Andes N9development platform, clip SRAM to72KB according toour practical needs; use RDA5876as the Bluetooth chip, implement connection andcommunication to the development platform through UART, and implement the connection toAPU through PCM audio interface; realize human-machine interface through button control ofexternal touchpad. In software aspect, we realized the transplantation of μC/OS-II RTOS in N9platform. Also, we realized the Bluetooth application program, USB host driver and systemapplication program through studying μC/OS-II, Bluetooth protocol stack and USB.Through the integration and test of hardware, software platform, we found that thecompatibility of USB/SD diver is excellent, reading rate reached165/900KB/s, which canmeet the requirements of high quality audio transmission. Through the test of audio spectrumin different modes, we could find: DAC module has high accuracy; the audio spectrum showa slight distortion in a reasonable range while tested in MP3mode at48KHz samplingfrequency; however, the audio spectrum show a more serious distortion in Bluetooth mode at48KHz, which related to the hardware circuit connection and Bluetooth radio transmission.These tests show that the Bluetooth audio application system fulfilled these functions:Bluetooth audio transmission, hands-free phone call and MP3media player., different kindsof USB/SD devices can be supported, which indicates it will have a far-ranging applicationin the future...