Serving a High- or Low-Priority Interrupt While the Main Routine Code Is Executing

When a high- or low-priority interrupt is requested while the main routine code is executing, the main routine execution is halted and the ISR is addressed. Upon a return from the ISR (by executing the RETFIE instruction), the main routine resumes execution.

Figure 1. Interrupt Execution: High/Low-Priority Interrupt While Executing Main Routine