23-06-2012, 06:05 PM
CS601: Microprocessor & Interfacing
Iterrupts.ppt (Size: 433.5 KB / Downloads: 54)
INTERRUPT
The meaning of ‘Interrupt’ is to break the sequence of operation.
While the cpu is executing a program, ‘interrupt’ breaks the normal sequence of execution of instructions, diverts its execution to some other program called Interrupt Service Routine (ISR).
After executing ISR , the control is transferred back again to the main program.
Purpose of Interrupts
Interrupts are particularly useful when interfacing I/O devices that provide or require data at relatively low data transfer rate.
Interrupt Sources
Hardware Interrupts (External Interrupts)
ex: NMI, INTR
Software Interrupts (Internal Interrupts and Instructions)
ex: INT n (Software Instructions)
NMI :-- Non Maskable Interrupt input pin which means that any interrupt request at NMI input cannot to masked or disabled by any means.
INTR:-- It can be masked using the Interrupt Flag (IF).