Embedded Linux, High-speed Data Acquisition System

Incorporating Linux with embedded system is a researching focus in the embedded field. This dissertation discusses the development method of embedded Linux system,and implements the high speed data acquisition system based on the embedded Linux system.When we develop the application based on the embedded Linux system we must first resolve how to build the embedded Linux OS.During the building we must consider several problems such as how to boot Linux,whether is the virtual memory mechanism necessary,how to select the file system and how to eliminate the dependment on disk. On above basis the article presents the key steps of builing the embedded Linux system on PC/104 module with Compact Flash card.The device driver which is a part of Linux kernel and stays all along in the computer memory is in essence the shared library of programs processing hardware. The device driver is so critical to Linux OS that its wrong could cause the system breakdown.This dissertation analyzes the elementary operating principle of the device driver in Linux,expatiates on the memory management,interrupt processing,I/O port and DMA processing.The high speed data acquisition system accomplishes mostly the data acquiring and data storing as soon as possible.How to transfer data from data acqusition card to hard disk is the key technology to ensure the whole system working rapidly and precisely. The traditional program control mode being CPU centre can not satisfy the requirement of the high speed data acquisition system.In this dissertation the DMA mode is adopted to complete the data trasferring in which hardware replaces software partly and in the result the transferring speed improves greatly.In conclusion,it is viable to build embedded Linux on PC/104 system and apply it to the measurement and control field in industry.