Contents
What is FIQ and IRQ?
In an ARM-based system, two levels of interrupt are available: fast interrupt request (FIQ) for fast, low-latency interrupt handling, and interrupt request (IRQ) for general interrupts.
What is the meaning of IRQ?
interrupt request
An IRQ (interrupt request) value is an assigned location where the computer can expect a particular device to interrupt it when the device sends the computer signals about its operation. For example, when a printer has finished printing, it sends an interrupt signal to the computer.
What are the different ARM processors?
ARM Processor Modes and Registers
| Mode | Function | Privilege |
|---|---|---|
| User (USR) | Mode in which most programs and applications run | Unprivileged |
| FIQ | Entered on an FIQ interrupt exception | Privileged |
| IRQ | Entered on an IRQ interrupt exception | |
| Supervisor (SVC) | Entered on reset or when a Supervisor Call instruction ( SVC ) is executed |
Which IRQ does LPT1 commonly used?
| IRQ Level | Common Use | Comments |
|---|---|---|
| 4 | COM1 or COM3 | |
| 5 | LPT2 | This is usually free as not many people have 2 parallel ports. Sound blaster cards usually use this. |
| 6 | Floppy disk controller | |
| 7 | LPT1 | Sound blaster cards can use this |
Why are interrupts necessary?
Interrupts are important because they give the user better control over the computer. Without interrupts, a user may have to wait for a given application to have a higher priority over the CPU to be ran. This ensures that the CPU will deal with the process immediately.
What is IRQ conflict?
An IRQ conflict happens when two devices attempt to use the same IRQ number, and the operating system or motherboard has no mechanism for accommodating this. These conflicts were common in older versions of Windows, but occur only rarely in modern versions of the operating system.