There are several operation modes available for the Interval Timer. The timer itself is a very simple 12-bit timer, with a 12-bit counter and a 12-bit compare register. An interrupt is generated if both registers match. A major application for these interval timers enabling the RL78’s low power operation. For example if you want to do a cyclic wake-up based on the internal sub-system clock, you can use the interval timer since it is running - even in Stop Mode - when the internal low speed oscillator is operating. The low speed internal oscillator together with the interval timer, enable very low power consumption down to 0.5µA during Stop Mode, but still have the capability to wake up the CPU based on the interrupt coming from the Interval Timer. The input clock for the interval timer can be either the 15kHz internal selector or the 32kHz sub-clock signal, the same as the real-time clock unit.