Events notify peripherals and the CPU about events that have happened, such as a state change in a peripheral. A peripheral may generate multiple events, where each event has a separate register in that peripheral's event register group.
An event is generated when the peripheral toggles the corresponding event signal and updates the event register to show an event has been generated, see figure Peripheral interface. An event register is cleared when firmware writes a 0 to that register. A peripheral can continually generate events when the event register is 1.