ABSTRACT
At present, with the rapid development of the MCU applications,the embedded systems as the core of microcontroller have been widely used in various fields. this paper is refer to the application of time and time measurement control, and developed a timer system which is base on AT89S51 SCM control. This paper mainly describes the use of MCU timer system, from the beginning of the designing of software, hardware, discussed both proceed to the design, testing and other aspects. Also made the evaluation in the the part of the completion of the function of the design conclusions. The design not only can achieve good opening, pause, reseting functions, and also can be accurate to 10 milliseconds. Therefore, there are more advantages in the time for precision. Finally through the practical application we proved its a reliable timer operation system, can produce a certain economic value.