Abstract: Interrupt mechanism is the core mechanism which decides the instantaneity of the RTOS.MQX is an open source,multitask support,preemptive RTOS which is maintained by Freescale.It will be widely used in the application of the ARM Cortex-M microprocessor.MQX interrupt mechanism has the characteristics of real-time response and dynamic management.The paper analysed the MQX interrupt operation mechanism of top half and bottom half,based on the ARM Cortex M4Kinetis series microcontroller,and put forward the evaluation algorithm which is used to describe the instantaneity of the RTOS,making the controllability of program running time clear.On this basis,according to the embedded software engineering basic principles,not constrained by the traditional program structure design methods,this paper proposed a basic principle describing the interruption program structure under MQX and the distribution of programming elements,which satisfies the requirements of program reusability and portability.

Key words: MQX,ARM Cortex-M4,Kinetis,Interrupt mechanism,Interrupt program frame