Research On Application Of TPMS Based On PIC MCUs

This paper summarized the present status and trends of TPMS development, expounded the basic principles and realizing methods of current TPMS projects, analysed the factors impacting the performance of tires and the mechanism of tire bursting, and lucubrated several subsistent key problems in normal TPMS projects, such as lower power comsumption, anti-interference, low cost and commonality of TPMS products, and etc., and proposed corresponding solutions.The author proposed a high performance-price ratio solution based on PIC MCUs, and finished a set of hardware prototype for experiment. The system was divided into two parts functionally: tire pressure measuring block and central monitoring block.The hardware composition was introduced respectively; hardware circuits of each block were also presented.in this paper. Performance and function of main chips were introduced in detail, such as the sensor SP12, rfPIC12F675 (MCU with embedded UHF transmiter), receiver rfRXD0420, PIC16F877, and some other important components like LCM (with a T6963C controller embeded) and etc.To enhance the anti-interference performance and realize low power consumption management, an active Low Frequency (LF) wake-up technology was adopted.As for software design, a dynamic time cycle measuring and transmitting method was proposed, and corresponding software arithmetics were given, combining LF wake-up technology with low power management thought. Taking into consideration severe electromagnetic interference environment of cars, a CRC (Cyclic Redundancy Check) arithmetic was added into the communication protocol frames, compositive software filtering methods were also used to enhance the reliability and presice of the system.Finally, part of the experiment results were shown on the base of the prototype system, conclusions and prospective to the future were also given.