Design Study Of A Certain Type Of Electronic Automotive Instrument

The first generation of auto-meter is based on the mechanism,people call them machine meter.The second generation of auto-meter ground on the principle of electric measure,viz making use of various of sensors to transform the non-electric variable to electric variable,generally we call them electric meter;The third generation of auto-meter is electronic auto-meter which is based up on stepping motor. The shortage of the first two generations is using soft axletree to achieve the point function. The development of modern car is leaning to high speed. The soft axletee is under the challenge of speed boosting ,because when the axletree circumrotate in high speed,it can be broken easily. At the same time, Overlong axletree will be distorted or retarded. For different type of car,the position of auto-meter will be restricted by the length and camber of the axletree. Those auto-meter can not satisfy the high-precision of signal and indication by reason of their low-precision design and manufacture.Electronic auto-meter is the trend of the development of auto-electronic technique .To surmount the error of principle and technics ,foreign manufacturers popularize digital auto-meter. At first , analog signals of sensor is changed into digital one's. Such as axletree or generator is replaced by sensors ,and become the transmission of mechanism or electricity into digital form. Secondly, display equipment of magnetic induction has been turn to stepping motor or digital display equipment.However, in our industry, due to the state of low level of auto-meter technique , simple figure ,weak of durability and reliability,we have a great distance from developed country. This thesis put forward a particular resolvent via the analyzes of the CHAN AN 338 auto-meter's requirement of functions .This resolvent make up of hardware and software.In software aspect,it introduce ten modules,such as setting of I/O port,setting of counter, interrupt control, AD conversion,driving of LCD, car Rpm calculation, car speed calculation , car odometer calculation, key scale.The level of developing electronic auto-meter in my company will be advanced by this research .