With the rapid development of urbanization in China, taxis, as an important means of transportation, have been chosen by more and more people. The traditional taxi meter has been used for more than ten years. For example, the automobile instrument is designed with 89S5 1 single chip microcomputer, and most functions can be realized with single chip microcomputer, which has certain advantages in stability, cost and usage habits. However, the single-chip computer program is not universal, and different chips have different instruction sets, so it is difficult to design and develop, and the cycle is long. If the system design is not good, then the system is not very stable and flexible enough, and it is difficult to realize the design with complex functions. The appearance of digital programmable devices such as FPGA has completely solved these problems. Different logics of FPGA can be executed in parallel, and different tasks can be processed at the same time, thus making the work efficiency of FPGA higher. At the same time, different modules can be designed according to different requirements to realize the required functions quickly.
The main task of this design is to design a taxi billing system with the functions of billing display, clock display and billing start prompt. The taxi billing system developed in this paper integrates the traditional hardware circuit from the design principle, adopts VHDL language and top-down design method, greatly shortens the research cycle, and is easy to make design modifications, and the corresponding modifications are included in the design documents.
In addition, this design is completed by Quartus II software. Quartus II software's good simulation and comprehensive functions make the design very convenient, and the verification and debugging of the design can be realized by using this software. The charging system has a large adjustment range in the time process to meet the different requirements of different situations. The billing system developed in this paper has the characteristics of novelty, simple structure, high performance and flexible operation and control, and has great market development and application prospects.
In recent years, computer technology and microelectronic devices have been widely used in engineering technology, and the intelligent instruments developed on this basis have developed rapidly in measurement accuracy, reliability, automation, application function and the depth and breadth of solving measurement and control technical problems. In this context, all instrument manufacturers are scrambling to launch a new generation of intelligent products. Many domestic manufacturers of electronic instruments are still at the technical level of the 1970s and 1980s, and their products are mostly composed of MSI devices and separate component circuits, which are no longer competitive in the market.
The meter designed by analog circuit and digital circuit has large scale and many devices, which leads to high failure rate and difficult debugging. For mode switching, mechanical switch is needed, which will lead to poor contact and make it difficult to realize the function for a long time. For this reason, we adopted a single-chip microcomputer for design, which is quite powerful. With less hardware and proper software, we can easily meet the design requirements and have strong flexibility. We can complete more additional functions through software programming. The switching of charging mode can be easily realized by software programming, which avoids the unstable factors brought by mechanical switch. With a better billing system, Levi passengers provide more convenient and efficient services.