RL78/G13 CHAPTER 16 INTERRUPT FUNCTIONS
R01UH0146EJ0100 Rev.1.00 848
Sep 22, 2011
Figure 16-10. Examples of Multiple Interrupt Servicing (2/2)
Example 3. Multiple interrupt servicing does not occur because interrupts are not enabled
Main processing INTxx servicing INTyy servicing
EI
1 instruction execution
RETI
RETI
INTxx
(PR = 11)
INTyy
(PR = 00)
IE = 0
IE = 0
IE = 1
IE = 1
Interrupts are not enabled during servicing of interrupt INTxx (EI instruction is not issued), therefore, interrupt request
INTyy is not acknowledged and multiple interrupt servicing does not take place. The INTyy interrupt request is held
pending, and is acknowledged following execution of one main processing instruction.
PR = 00: Specify level 0 with ××PR1× = 0, ××PR0× = 0 (higher priority level)
PR = 01: Specify level 1 with ××PR1× = 0, ××PR0× = 1
PR = 10: Specify level 2 with ××PR1× = 1, ××PR0× = 0
PR = 11: Specify level 3 with ××PR1× = 1, ××PR0× = 1 (lower priority level)
IE = 0: Interrupt request acknowledgment is disabled
IE = 1: Interrupt request acknowledgment is enabled.
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