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What is multiple interrupt line?
Multiple Interrupt Lines: The processor picks the interrupt line with highest priority. Software Poll: The priority is determined by the order in which the modules are polled. Daisy Chain (Hardware Poll, Vectored): The priority is determined by the order in which the modules are polled.
How multiple interrupt signals are handled in a system?
Multiple interrupt requests require a mechanism to handle each interrupt. If an interrupt of a higher priority is received while an ISR associated with a lower priority interrupt is being executed, the ISR of higher priority interrupt commences execution immediately.
What happens if two or more interrupts occur at the same time?
Answer: When multiple interrupt requests of an identical level occur simultaneously, priority is given to the interrupt source that has the smaller vector number.
What happens when an interrupt?
An interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention. Whenever an interrupt occurs, the controller completes the execution of the current instruction and starts the execution of an Interrupt Service Routine (ISR) or Interrupt Handler.
Do all interrupts have the same priority?
An interrupt request of a higher priority than the current context (whether a non-interrupt, or an interrupt) will interrupt that context. Interrupt requests with the same priority as the current context will not interrupt. In the case you describe, one interrupt would always be serviced first, then the other.
What does it mean to have multiple interrupt lines?
Multiple Interrupt Lines: Simplest solution to problems above is to provide multiple interrupt lines that will result in immediate recognition of interrupting device. Priorities can be assigned to different interrupts and interrupt with the highest priority must be selected for service in case a multiple interrupt takes place.
When do you need to assign priority to multiple interrupts?
However, when there are multiple interrupts at a single time, there will be a need to assign priorities. These 4 methods have their own way of assigning priorities: Multiple Interrupt Lines: The processor picks the interrupt line with highest priority.
Why are there more than one interrupt driven I / O module?
This allows multiple modules to be handled at the same time. However, it is not practical to assign many bus lines and processor pins to interrupt lines. One of the reasons is that there might be more than one I/O module attached to a single line. This defeats the purpose of this technique.
How does an I / O controller receive an interrupt signal?
The device signals the I/O controller that is ready to retrieve input, the output is complete or that an error has been generated. The CPU receives the interrupt signal on the interrupt-request line and transfer control over the interrupt handler routine.