RL78/G15 CHAPTER 14 INTERRUPT FUNCTIONS
R01UH0959EJ0110 Rev.1.10 Page 620 of 765
Mar 7, 2023
Example 2. Multiple interrupt servicing does not occur due to priority control
RETI
Main processing INTxx processing INTyy processing
INTxx
(PR = 10)
INTyy
(PR = 11)
IE = 0
IE = 1
IE = 1
IE = 0
EI
RETI
EI
1 instruction
execution
Interrupt request INTyy issued during servicing of interrupt INTxx is not acknowledged because its priority is lower than
that of INTxx, 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 xxPR1x = 0, xxPR0x = 0 (higher priority level)
PR = 01: Specify level 1 with xxPR1x = 0, xxPR0x = 1
PR = 10: Specify level 2 with xxPR1x = 1, xxPR0x = 0
PR = 11: Specify level 3 with xxPR1x = 1, xxPR0x = 1 (lower priority level)
IE = 0: Interrupt request acknowledgment is disabled
IE = 1: Interrupt request acknowledgment is enabled.