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RL78/G1A CHAPTER 16 INTERRUPT FUNCTIONS
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
INTxx
(PR = 11)
INTyy
(PR = 00)
RETI
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.
R01UH0305EJ0200 Rev.2.00 712
Jul 04, 2013