Interrupts of 8085
I CHAPTER 1: INTRODUCTION TO INTERRUPTS
1.1 What Is An Interrupt? Before we move into a detailed study of the 8085 Interrupts we must at first get an idea about what an Interrupt is. Looking at the literal meaning of interrupt, one can say that interrupting something or someone is stopping the thing or person from their normal course of action. This is the same in the case of a microprocessor too. The Intel 8085 microprocessor has this feature called the Interrupt which enables the user to stop the execution of a current action for a specified interval of time. Using this Interrupt feature one can pause the current sequence of actions being executed by the microprocessor to make it execute some other action. The interrupt I/O is a process of data transfer whereby an external device or a peripheral can inform the processor that it is ready for communication and it requires attention. The process is initiated by an external device and is asynchronous, meaning that it can be initiated at any time without reference to the system clock. But after that, the response to an interrupt request is controlled solely by the microprocessor. The interrupt process allows the microprocessor to respond to these external requests for attention or service on a demand basis and leaves the microprocessor free to perform other tasks.
1.2 What Happens When The Microprocessor Is Interrupted? When the Microprocessor receives an interrupt signal, it suspends the currently executing program and jumps to an Interrupt Service Routine (ISR) to respond to the incoming interrupt. Each interrupt has its own ISR. After the ISR has been executed an the purpose of the interrupt served, the processor returns to execute the task it had been engaged in previously or attend to any other pending interrupt requests.
1.1 What Is An Interrupt? Before we move into a detailed study of the 8085 Interrupts we must at first get an idea about what an Interrupt is. Looking at the literal meaning of interrupt, one can say that interrupting something or someone is stopping the thing or person from their normal course of action. This is the same in the case of a microprocessor too. The Intel 8085 microprocessor has this feature called the Interrupt which enables the user to stop the execution of a current action for a specified interval of time. Using this Interrupt feature one can pause the current sequence of actions being executed by the microprocessor to make it execute some other action. The interrupt I/O is a process of data transfer whereby an external device or a peripheral can inform the processor that it is ready for communication and it requires attention. The process is initiated by an external device and is asynchronous, meaning that it can be initiated at any time without reference to the system clock. But after that, the response to an interrupt request is controlled solely by the microprocessor. The interrupt process allows the microprocessor to respond to these external requests for attention or service on a demand basis and leaves the microprocessor free to perform other tasks.
1.2 What Happens When The Microprocessor Is Interrupted? When the Microprocessor receives an interrupt signal, it suspends the currently executing program and jumps to an Interrupt Service Routine (ISR) to respond to the incoming interrupt. Each interrupt has its own ISR. After the ISR has been executed an the purpose of the interrupt served, the processor returns to execute the task it had been engaged in previously or attend to any other pending interrupt requests.