WKT CTRL addressOffset = 0x000

The WKT interrupt must be enabled in the NVIC to wake up the part using the self wake-up counter.

Table 1. WKT registerName = CTRL addressOffset = 0x000
Bit Symbol Value Description Reset value
0 CLKSEL   Select the self wake-up timer clock source. 0
    0 Divided IRC clock. This clock runs at 750 kHz and provides time-out periods of up to approximately 95 minutes in 1.33 μs increments.
Note: This clock is not available in not available in Deep-sleep, power-down, deep power-down modes. Do not select this option if the timer is to be used to wake up from one of these modes.
    1 Low power clock. This is the (nominally) 10 kHz clock and provides time-out periods of up to approximately 119 hours in 100 μs increments. The accuracy of this clock is limited to +/- 40 % over temperature and processing.
Note: This clock is available in all power modes. Prior to use, the low-power oscillator must be enabled. The oscillator must also be set to remain active in Deep power-down if needed.
1 ALARMFLAG   Wake-up or alarm timer flag. -
    0 No time-out. The self wake-up timer has not timed out. Writing a 0 to has no effect.  
    1 Time-out. The self wake-up timer has timed out. This flag generates an interrupt request which can wake up the part from any reduced power mode including Deep power-down if the clock source is the low power oscillator. Writing a 1 clears this status bit.  
2 CLEARCTR   Clears the self wake-up timer. 0
    0 No effect. Reading this bit always returns 0.  
    1 Clear the counter. Counting is halted until a new count value is loaded.  
31:3 -   Reserved. -