SWCU191 February 2022 CC1311P3 , CC1311R3 , CC2651P3 , CC2651R3 , CC2651R3SIPA
The processor supports both level-sensitive and pulse interrupts. Pulse interrupts are also described as edge-triggered interrupts. A level-sensitive interrupt is held asserted until the peripheral deasserts the interrupt signal. The interrupt sources in the CC13x1x3 and CC26x1x3 device platform devices are normally level. That is, they stay active until the interrupt source is cleared in the peripheral. Typically this happens because the interrupt service routine (ISR) accesses the peripheral, causing it to clear the interrupt request. To ensure the NVIC detects the interrupt, the peripheral must assert the interrupt signal for at least one clock cycle.
When the processor enters the ISR, it automatically removes the pending state from the interrupt (see Section 5.2.2.2). For a level-sensitive interrupt, if the signal is not deasserted before the processor returns from the ISR, the interrupt becomes pending again, and the processor must execute its ISR again. As a result, the peripheral can hold the interrupt signal asserted until it no longer needs servicing.