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What is an interrupt in ARM?
An interrupt is the automatic transfer of software execution in response to a hardware event that is asynchronous with the current software execution. This hardware event is called a trigger.
How do you handle ARM interrupts?
The steps required to enable interrupts safely in an IRQ handler are:
- Construct the return address and save it on the IRQ stack.
- Save the work registers, non callee-saved registers and IRQ mode SPSR.
- Clear the source of the interrupt.
- Switch to System mode, keeping IRQs disabled.
What is the type of ARM interrupts?
There are two types of interrupts available on ARM processor. The first type is the interrupt caused by external events from hardware peripherals and the second type is the SWI instruction.
What are the three types of ARM exceptions?
The following exceptions handlers are available:
- arm-da.o. Data abort, initiated when trying to access bad memory locations.
- arm-pfa.o. Prefetch abort, initiated when trying to read the next instruction from a bad memory location.
- arm-swi.o. Software interrupt.
- arm-udf.o.
How does an ARM processor execute an interrupt service?
Now ARM processor updates the values of the stack pointer, linker register (LR), PC (program counter) with new values according to the interrupt service routine. The link register contains the type of interrupt return address. After that interrupt services routine starts to execute and finish its execution.
What’s the difference between interrupt and exception in ARM Cortex-M?
Because, in ARM Cortex-M literature both terms are used to refer to interrupts and exceptions. Although there is a minor difference between interrupt and exception.
What are the two types of interrupts in arm?
There are two types of interrupts available on ARM processor. The first type is the interrupt caused by external events from hardware peripherals and the second type is the SWI instruction.
Why does the ARM core have only one FIQ pin?
The ARM core has only one FIQ pin, that is why an external interrupt controller is always used so that the system can have more than one interrupt source which are prioritized with this interrupt controller and then the FIQ interrupt is raised and the handler identifies which of the external interrupts was raised and handle it.