21-01-2013, 04:18 PM
8085 interrupts
8085 interrupts.ppt (Size: 5.38 MB / Downloads: 84)
Interrupt process
enable by writing EI.
mp checks INTR line at each instruction.
if INTR is high, mp completes the current instr, disables Interrupt Flip-flop, sends INTA signal.
An RST instruction is inserted by INTA through external hardware.
Mp saves the memory address of the next instruction into stack. Program control is transferred to CALL location. The service routine starts at CALL location.
At the end of the subroutine Interrupt enable Flag is enabled again by EI instruction.
The last instruction of the subroutine is RET to transfer back the program control to its original address.