Research And Implementation Of The Embedded System Of Underwater Acoustic Communication Based On OMAP

As human's exploration of marine resources, and the promotion of marine safety consciousness, people have urgent requirement for the development of underwater communication technology. In the underwater acoustic communication system, the MODEM is responsible for sending and receiving signals and it is the network communication node of underwater acoustic communication. The digital signal processing platform is an important part of underwater acoustic MODEM, it is responsible for the implementation of the modulation and demodulation algorithm of underwater acoustic communication. Considering the characteristics of underwater acoustic communication, the design of digital signal processing platform should not only meet the requirements of high speed data processing, but also a highly integrated and ensure low power consumption in terms of hardware.This paper puts forward a kind of underwater acoustic communication design scheme of digital signal processing platform, including the design of the hardware platform; detailed building embedded Linux system. Hardware platform uses MCU+OMAP+FPGA structure, MCU is responsible for monitoring and management, OMAPL138 on core board of OMAP integrating ARM and DSP processor, combines the ability of control function of the ARM and digital signal processing of the DSP, the FPGA module implements the algorithm which is used to communicate on the platform. In this paper, we mainly talk about the design of each part and the interface between the modules.Software part of this platform's main work is to build an embedded Linux system on the OMAP core board of the signal processing platform as a control center of the platform. With the help of the operating system, it can better manage the equipment resources of the platform, and support the network communication to make the communication more convenient to the host. Embedded development generally adopt the method of master-target, this article first sets up the development environment on a host computer and installs the necessary software tools; then according to the startup mode of OMAP dual-core processor, and combined with the requirements of the signal processing platform, the embedded Linux system is customized in line with the hardware platform, including U-Boot, Linux kernel and root file system's customization and transplantation. Then the corresponding drivers are designed according to the hardware devices' using requirements on the platform. This article mainly develops the driver of the communication interface between OMAP core board and FPGA, including GPIO control driver and UPP data bus driver, and ioctl method and memory mapping are used to realize character device's driver. For OMAPL138 dual-core processor, this paper uses DSPLINK to develop dual-core communication, make the underwater acoustic communication software running on the DSP core and the embedded Linux system on the ARM core can perform data interaction and work together.At the end of this article, communication tests of OMAP core board peripheral interface are excuted to validate the correctness of data transmission, including SPI, EMIF, serial port and etc. In order to meet the different requirements of using platform in debugging phase and normal work phase, the compiled image files can be put into the relevant folder on the host and download through TFTP, they can also be separately burned to the NAND FLASH on the platform and start from the FLASH. Through the test of launching, the embedded Linux system on the platform can run normally, which lays the foundation for the subsequent application software's development. Finally the test results of data communication shows that the designed driver can be implement the communication correctly between core board and the FPGA.