Renesas rl78 User Manual

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

1 instruction execution

RETI

INTxx

(PR = 11)

INTyy

(PR = 00)

RETI

IE = 0

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