简要介绍了Blackfin561的DMA功能和BMP文件的格式,叙述了在基于Blackfin561的 嵌入式操作系统uClinux下并行外部接口(PPI)驱动程序的框架,以及驱动程序中各个函数的具体功能与实现方式。完成了虹膜图像数据的采集,并对图像数据进行了预处理,提取其中所有亮度信息,生成BMP图像文件。同时指出了调试过程中常遇的问题以及解决方法。 关键词:嵌入式系统;设备驱动程序;虹膜图像采集;DMA;PPI Abstract: In this paper, the DMA function of Blackfin561 and BMP image file are simply introduced, and the architecture of parallel peripheral interface (PPI) driver based on embedded OS uClinux running on Blackfin561 is given, further more, the functions and achievement of each function in the driver are introduced. The image data is captured and pretreated, in this process, all the brightness signals are pick-up, then generate bmp image file. At the end of the paper, the problems often meet in debug and the solutions are present. Key words: embedded system;device drivers;iris image sampling;DMA;PPI