What Is a Break In Service?

Interrupt service program. The processor processes "emergency", which can be understood as a service, which is completed by executing a specific program prepared in advance. This kind of program for processing "emergency" is called-interrupt service program.

Interrupt service routine

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Interrupt service program. The processor processes "emergency", which can be understood as a service, which is completed by executing a specific program prepared in advance. This kind of program for processing "emergency" is called-interrupt service program.

Chinese name

Interrupt service routine

Foreign name

Interrupt Service Routines

Authentic

Processes related to each type of I / O device

Interrupt service routine

Processor handles "urgent"

Interrupt processing

Protection of interrupted process sites

The process associated with each type of I / O device has an address near the bottom of the memory, called the interrupt vector. It includes the entry address of the interrupt service routine.

While the central processing unit was processing internal data, an emergency occurred outside the world, requiring the CPU to suspend the current work and handle the emergency. After processing, return to the original interrupted address and continue the original work. This process is called interruption. The part that implements this function is called an interrupt system. The request source for applying for CPU interrupt is called an interrupt source. The interrupt system of a microcontroller generally allows multiple interrupt sources. When multiple interrupt sources request interrupts from the CPU at the same time, an interrupt priority exists The right issue. Usually according to the priority level of the interrupt source, the most urgent interrupt request source is processed first, that is, the interrupt request with the highest response level is processed first.

Interrupt processing:

(1) Protect the scene of the interrupted process. In order to make the process return to the interruption point accurately after the interrupt processing is over, the system must save the values of the current processor program status word PSW and program counter PC.

(2) Analyze the cause of the interruption and switch to the corresponding interruption handler. When multiple interrupt requests occur simultaneously, the interrupt request from the interrupt source with the highest priority is processed.

(3) The scene of the interrupted process is resumed, and the CPU continues to execute the originally interrupted process.