Interrupts
9 likes11,812 views
This document discusses interrupts, which are unexpected hardware-initiated subroutine calls that temporarily suspend program execution. There are different types of interrupts, including external, internal, software, and hardware interrupts. Interrupts are used for input/output data transfers with peripheral devices, emergency situations, event-driven programs, and real-time applications. When an interrupt occurs, the processor's status is saved and it branches to an interrupt service routine to handle the interrupt before returning to the main program.
Interrupts
- 1. PRESENTATION ON INTERRUPTS
- 2. INTERRUPTS It is an unexpected hardware initiated subroutine call or jump that temporarily suspends the running of the current program. Interrupt is a process where an external device can get the attention of the microprocessor. Initiation of I/O operation. Completion of I/O operation. An interrupt may be either: Edge Sensitive Level Sensitive
- 3. CATEGORIES OF INTERRUPTS Maskable Interrupts. Non-Maskable Interrupts. Vectored Interrupts. Non-Vectored Interrupts.
- 4. TYPES OF INTERRUPTS External Interrupt. Internal Interrupt. Software Interrupt. Hardware Interrupt.
- 5. USES OF INTERRUPTS Input/Output data transfers for peripheral devices. Emergency situations like power down. Input signals to be used for timing purposes. Event driven programs. Real time response applications and in multitasking system.
- 6. INTERRUPT CONTROLLED I/O TRANSFERS It is an asynchronous mechanism. Each device is connected to an interrupt line. When it needs service, it asserts the interrupt line to request the processors attention. The status of being executed must first be saved & it will be saved on stack If one or more device is connected to the interrupt line, the processor ends to know which device service routine it should branch to. The identification of the device requesting service can be done in either hardware or software or a combination of both.
- 7. INTERRUPT CONTROLLED I/O TRANSFERS Software Determination of the Requesting Device. Enable Interrupts. Request an Interrupt. Servicing the Interrupt. Returning to main program. Interrupt Latency & Interrupt Response Time. Interrupt Latency. Interrupt Response Time.
- 8. INTERRUPT CYCLE In this cycle, CPU has to check for an interrupt each time an instruction is executed. The interrupt enable flip-flop IEN can be set & cleared with two instructions namely ION & IOF. ION: Interrupts Enable On. IOF: Interrupts Enable Off. When IEN=0, Flag can’t interrupt computer. When IEN=1,Flag can interrupt computer.