25.6.6 Interrupts

The EIC has the following interrupt sources:

• External interrupt pins (EXTINTx). See 25.6.2 Basic Operation.
• Non-maskable interrupt pin (NMI). See 25.6.4 Additional Features.

Each interrupt source has an associated interrupt flag. The interrupt flag in the Interrupt Flag Status and Clear register (INTFLAG) is set when an interrupt condition occurs (NMIFLAG for NMI). Each interrupt, except NMI, can be individually enabled by setting the corresponding bit in the Interrupt Enable Set register (INTENSET=1), and disabled by setting the corresponding bit in the Interrupt Enable Clear register (INTENCLR=1). As both INTENSET and INTENCLR always reflect the same value, the status of interrupt enablement can be read from either register.

An interrupt request is generated when the interrupt flag is set and the corresponding interrupt is enabled. The interrupt request remains active until the interrupt flag is cleared, the interrupt is disabled, or the EIC is reset. See the INTFLAG register for details on how to clear interrupt flags. The EIC has one interrupt request line for each external interrupt (EXTINTx) and one line for NMI. The user must read the INTFLAG (or NMIFLAG) register to determine which interrupt condition is present.