fiq & irq handler — arm

Question

I am new to arm & have some doubs related to IRQ & FIQ. Please try to clarify these.
How many number of FIQ & IRQ channel arm have ?
And what number of h

Answer 1

Actually the question is a bit tricky. You must specify in the question to which architecture in ARM you work. ARM v7-A and ARM v7-R Architecture Reference Manual (ARM ARM) specifies one FIQ and one IRQ, as many already answered. But ARMv7-M (used in Cortex-M processors) integrates a interrupt controller in the processor, and thus offers one NMI (instead of FIQ) and up to 240 IRQ lines.

For more information: ARMv7 A and ARMv7-R Architecure reference manual: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0406c/index.html

ARMv7-M Architecture Reference Manual: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0403e.b/index.html

As an example, Cortex M4 specs sheet: http://www.arm.com/products/processors/cortex-m/cortex-m4-processor.php