Single-Chip Microcontrollers User's Manual

521

CHAPTER 22 INTERRUPT FUNCTIONS

Figure 22-16. Multiple Interrupt Example (2/2)

Example 3. A multiple interrupt is not generated because interrupts are not enabled

Because interrupts are not enabled in interrupt INTxx servicing (an EI instruction is not issued),

interrupt request INTyy is not acknowledged, and a multiple interrupt is not generated. The INTyy

request is reserved and acknowledged after 1 instruction execution of the main processing.

PR = 0 : Higher priority level

IE = 0 : Interrupt request acknowledge disable

Main Processing

INTxx

Servicing

INTyy

Servicing

INTxx

(PR = 0)

1 Instruction

Execution

IE = 0

INTyy

(PR = 0)

IE = 0

RETI