tailieunhanh - Model-Based Design for Embedded Systems- P74

Model-Based Design for Embedded Systems- P74: This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. | 716 Model-Based Design for Embedded Systems m m m Ax input a b FIGURE IMU simulation. The behavior of the interface can be summarized as follows The interface is always expecting data so when no data are received the interface status does not change. When the IBIS sends a command the interface sends signals to the SH and the ADC to start the data acquisition. The SH holds the signal while the ADC converts it to digital data. When the conversion is finished the ADC informs the interface and sends the digital data. Smart Sensors Modeling Using VHDL-AMS 717 The interface transmits the data to the IBIS bus and waits for new commands. Simulation and Validation Once the models for the complete IMU system have been developed it is possible to cosimulate the entire system. This simulation see Figure involves the three accelerometers and the three gyroscopes with their corresponding excitation signals and the IBIS bus requesting and receiving data. This simulation shows the complete process of acquiring the signal after the IBIS sends the command until the data is transmitted to the bus with the main intermediate signals. Each sensor has been assigned to one address so when the IBIS wants data from one sensor it sends a frame composed of an address and a command. When the addressed sensor receives the command from the IBIS the data capture takes place. When the process is finished a signal is activated to indicate that the conversion has finished and the final data is sent through the bus. Conclusions This chapter shows a VHDL-AMS approach to behavioral modeling of MEMS-based microinstrumentation using a design methodology with a distributed architecture. The development of behavioral models plays an important role in the design process and thanks to the mixed-signal hardware description languages it is possible to cosimulate the entire system composed of elements of a different nature. These models allow reducing simulation time and