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RL78/G1P
CHAPTER 15 INTERRUPT FUNCTIONS
R01UH0895EJ0100 Rev.1.00
590
Nov 29, 2019
Figure 15-10. 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.