Research And Implementation Of Secure Digital Interface On Personal Digital Assistant

On the basis of solution and implementation of embedded Personal Digital Assistant designed specifically for small and medium business, the design and implementation of Secure Digital interface of Personal Digital Assistant based on Windows CE.NET is done, which focuses on the design of hardware interface of SD card, card detect program, SD host controller device driver and Interrupt Service Program in Windows CE.NET operation system, etc.The hardware platform of N30 Personal Digital Assistant established upon Samsung's S3C2410A microprocessor, which contains SD controller itself. The embedded operation system is Windows CE.NET. The standard SD interface was functionally extended using General Purpose Input and Output pins. As to software, the Windows CE.NET operation system must be ported to ARM platform at first. Then the device driver of SD interface is developed. After initialization of SD controller registers of SD host, the device driver wait for insert of cards. When card is plugged in or plugged out, the detection pin will trigger system interrupt, and then the Interrupt Service Program starts to detect the status of card. The device driver will get the type of inserted card and load the driver of it when card is plugged in. The delay-sampling and multi-sampling for de-bounce are employed for the system crash caused by plug-in and plug-out card repeatedly.The test results show that the design of SD interface and its device driver on N30 PDA work well, and it also meets the storage requirements from users, and the delay-sampling and multi-sampling for de-bounce miss the de-bounce time and reduce the frequency of system crash caused by plug-in and plug-out SD card repeatedly.