Design And Realization Of Automatic Audio Switcher Based On ARM

Automatic audio switcher is one part of audio switch system. Transmission center of broadcast and television department needs to monitor multicenter audio signal, and choose one of them as the broadcast signal. To help judging whether the transmission is working order, it also needs to monitor the received signal that has been transmitted. Along with the improvement of broadcast and television monitor technology and the establishing of monitor net, the transmitting center needs to have the transmitting log and audio signal database to verify the monitor results. Now, transmission center monitor the transmission and switch the signal by man power. The work efficiency is low, and when meet an emergency the response is not timely. The watchers have huge work pressure if there are several programs. Now the transmission center has not the database of audio signal. We develop the audio switch system to guarantee the program transmitting safely, well and continuously, to intelligentize, scientize managing the devices, to lighten the work intension of the watch and improve the work efficiency. The system is made up of monitor and control station, hard disk record device and automatic audio switcher. One switcher monitors and switches one program. The switchers communicate with monitor and control station through Ethernet. Recording device such as recording card record the signal from switcher and send it to the station to save and play. Through the monitor and control station, we can control the switcher, monitor every signal's wave and audio switcher's state. ARM (Advance RISC Machine), is the name of a corporation, the name of a series of MCU and the name of a technology. At present, the MCU that have the ARM IP core are used widely in industry control, consume electronic product, communication system, network, wireless system and so on. The product used ARM technology is 75% in 32 bit RISC product market. ARM technology is infiltrating through our aspect of lives. Many semiconductor corporation purchase ARM core from ARM, and add appropriate peripherals depend on their used fields, then manufacture ARM MCU chip themselves. At present, tens of huge semiconductor corporation use ARM authorization, so there are more third party develop tools, software sustain ARM technology. Thus the products based on ARM are cost-effective, accepted easily by consumer and competitive. The thesis mainly introduces the automatic audio switcher based on ARM developed by ourselves. Depend on the needs of audio switch system, the switcher realize these functions: Switch: to assure the system stability, there are automatic, manual, remote control switch ways. Automatic way is that when judge one channel is out of order through monitor the signal, the signal automatically switches to the low priority channel. Three ways is independent with each other to assure the system is credible. Display: the switcher's work state and signal's state are displayed through LCD. Communication: audio switchers and monitor and control station can make up Ethernet through TCP/IP, exchange informations and control commands. Depend on the characteristics of the embedded system development, set up a development platform is a strategic thinking and has practical significance. So the thesis developed an embedded system development platform based on ARM firstly after analyzed the function of audio switcher and the trend and actuality of embedded system. The platform selects SamSung S3C44B0X which has ARM7TDMI core as CPU. S3C44B0X has abundant peripherals and is designed to provide a cost-effective and high performance micro-controller solution for hand-held devices and general applications. We use 2 pieces of 4M*16Bit SDRAM as data memory and configure the bus width as 32 bit, use 4M*16Bit FLASH as program memory, burn the FLASH by JTAG. We select EEPROM to save all kinds of parameters. Because S3C44B0X is not a net processor, we use RTL8019AS to design Ethernet interface circuit. RTL8019AS is a highly integrated Ethernet Controller which offers a simple solution to implement a Plug and Play NE2000 compatible adapter with full-duplex and power down features. The serial communication part is standard RS232 interface. In addition, the platform has LCD and keyboard. The software platform is developed by ADS1.2 based which we port μCOS –II to S3C44B0X. μCOS –II is an open source and portable RTOS and it is widely used step by step for it's little kernel, rich system service, easy handling and...