簡要介紹了Blackfin561的DMA功能和BMP文件的格式，敘述了在基于Blackfin561的
嵌入式操作系統uClinux下并行外部接口（PPI）驅動程序的框架，以及驅動程序中各個函數的具體功能與實現方式。完成了虹膜圖像數據的采集，并對圖像數據進行了預處理，提取其中所有亮度信息，生成BMP圖像文件。同時指出了調試過程中常遇的問題以及解決方法。
關鍵詞：嵌入式系統；設備驅動程序；虹膜圖像采集；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