EINT2

EINT2 is a term used in some microcontroller and system-on-chip families to denote the second external interrupt input line. External interrupts provide a mechanism for an external device, such as a button or sensor, to signal the processor asynchronously, without the need for continuous polling.

In typical implementations, EINT2 can be configured for different triggering modes, including edge-triggered (for example, on a rising or falling edge) or level-triggered operation. Many devices also offer a selectable input polarity, optional input filtering or debouncing, and the ability to mask or unmask the line. EINT2 is usually integrated into the system’s interrupt controller, allowing it to be assigned a priority relative to other interrupts.

Configuration and handling generally follow a common pattern. The pin associated with EINT2 is declared and routed through a pin-mux or GPIO subsystem. The interrupt's trigger condition is configured in dedicated registers, and a status or pending flag is provided to indicate the event. Software typically clears the flag in the interrupt service routine after processing, and the interrupt line is enabled in the controller with an assigned priority. In many designs, EINT2 can wake the processor from low-power states.

Usage examples include detecting a user button press, signaling from a sensor, or wake-up events. The exact capabilities, register names, and wiring of EINT2 vary among devices, so reference manuals or datasheets should be consulted for precise implementation details. See also external interrupts and the device’s interrupt controller for broader context.