The Research And Implementation Of The Hardware And Software System For LIS3DH Acceleration Sensor In Android Operating System

Android is an open embedded operating system platform launched by Google, the key component which it is unnegligible in its application is sensor. Currently, the chanllenges of sensor application development in Android smartphone mainly come from system-level hardware and software design, and embedded software development. The thesis completed the research and implementation of the hardware and software system of the LIS3 DH acceleration based on I2 C in Android smartphone system, mainly contained the design and implementation of I2 C interface control module, the driver in Linux and the application related to acceleration sensor. The concrete content and work is as follows:Firstly, the paper studied the LIS3 DH acceleration sensor principle. According to the function structure of the LIS3 DH sensor, we configured the various function module. And according to its application feature, we analysed how to use the LIS3 DH sensor, and how to get the sensor data.Secondly, the paper designed an I2 C interface control module, the module mainly contains I2 C bus interface, the control register interface, clock generation module, I2 C main controller, interrupt control module and arbitration logic module, to communicate with acceleration sensor by I2 C interface. The design adopts the method of I2 C communicating with EEPROM memory producted by the standard manufacturer, which simulating and verificating indirectly that it can initialize the sensor and complete the data sending and reception operation to the acceleration sensor through I2 C interface, because there is no LIS3 DH sensor verilog module, we use 24xx128 EEPROM verilog module replace with sensor verilog module. Besides, the design uses the way of the mutual authentication of two I2 C modules, furtherly validating the several function of I2 C in the state of master and slave machine. Next we completed the logic synthesis analysis and FPGA simulation verification.Thirdly, according to the acceleration sensor subsystem architecture, we divided the driver in Linux into two parts: I2 C driver and sensor driver. According to the I2 C architecture in Linux, we completed the I2 C driver for LIS3 DH acceleration sensor, and presented the detailed process of detecting the sensor device by the method of probe. According to the driver function division, we divided the sensor driver design into several modules: the driver of sensor feature set module, character device driver module, file system module, and input subsystem module. In the driver we use three concurrent control mode, to maintain the stability and security of driver. Then in Linux2.6, we modified the related configuration file, and completed the kernel debug and driver compile, then we got the sensor drive file which can drive the LIS3 DH sensor to work normally.Fourthly, according to the implement mechanism of HAL, the paper presentd the implementation of HAL interface. We analysized the work flow of HAL, and researched deeply the principle how to open the sensor device. After opening the sensor device, HAL need to do the coordinate transformation and data process. Next the application can access the HAL.Fively, the paper completed Java source code design related to the acceleration sensor application, then we set up Android development environment, completing the software debug of sensor.