NEC uPD78054 User Manual
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CHAPTER 21 INTERRUPT AND TEST FUNCTIONS
Main Processing
INTxx
Servicing
Servicing
INTyy
Servicing
Servicing
INTxx
(PR=0)
(PR=0)
1 Instruction
Execution
Execution
IE=0
INTyy
(PR=0)
(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