Driver Design And Implementation Of Intelligent Mini Projector Based On The Android Platform

With the rapid development of digital technology, micro-projection technology is gradually applied to the business office, education, military and other fields. Intelligent mini projector has large information storage capacity, small size, light weight and low power consumption. It can be used for operational command and electronic map display. Compared to most mature technology products, mini projector is still in the stage of development, so research in this field is important.In this dissertation, software platform of micro-projector system is designed and optimized. Driver design and implementation for an operation system is the core work, which includes system management, peripheral communications, human-computer interaction and information security units. Combination of the digital light processing technology and embedded technology can meet the needs well.Embedded microprocessor is the hardware-base of system management unit, while android operating system manages the software and hardware resources. Android optimized the linux kernel and builded the java runtime environment. So driver design for peripheral communications and human-computer interaction units is not just the kernel module. It also need to make the appropriate changes for the android framework.I2C and SPI are involved in the communication unit, corresponding subsystems are exist in the linux kernel. For security reasons, i2c-dev and spi-dev are not used, but implemented as a character device driver. Since android uses the hardware abstraction layer to access the device nodes, analyzing the structure of abstraction layer can help building a stub module. System service and the hardware abstraction layer module are implemented in two different languages, so JNI is needed. Communication between application and the system service is based on the binder interprocess communication.Human-computer interaction unit is designed for input and projection display. Drivers are based on the framebuffer and standard input subsystem, since android can get messages from the device node and the distribute it.For stability, all the functional units are tested and verified. The U-Boot, linux and android are optimized. The scheduled work objectives are basically completed.