505
CHAPTER 21 INTERRUPT AND TEST FUNCTIONS
Main Processing
INTxx
Servicing
INTyy
Servicing
INTxx
(PR=0)
1 Instruction
Execution
IE=0
INTyy
(PR=0)
IE=0
RETI
RETI
EI
Figure 21-16. Multiple Interrupt Example (2/2)
Example 3. A multiple interrupt is not generated because interrupt is disabled
Because interrupts are disabled during interrupt INTxx servicing (EI instruction is not issued), interrupt request
INTyy is not acknowledged, and a multiple interrupt is not generated. INTyy request is reserved and acknowledged
after execution of one main processing instruction.
PR = 0 : High priority level
IE = 0 : Interrupt request acknowledgment disabled
To Next Page
Loading...
