33.4.2 Postscaler

A variable postscaler divides the WDT prescaler output and allows for a wide range of time-out periods. User software may select the postscaler setting for the WDT in Run and Sleep mode. The postscaler is controlled by the RMPS[4:0] bits (WDTCON[12:8]) in Run Mode and SMPS[4:0] bits (WDTCON[5:1]) in Sleep/Idle Mode, which allows the selection of 32 settings, from 1:1 to 1:2147483648. Using the postscaler, time-out periods ranging from 1 ms to 24 days can be achieved.

The RMPS[4:0] selects the postscaler value for the Run Mode Counter. The RMPS[4:0] bits can only be changed when the ON(WDTCON[15]) bit is cleared.

The SMPS[4:0] selects the postscaler value for the Sleep Mode Counter. The SMPS bits can only be changed when the ON bit is cleared.

The WDT module time-out period is directly related to the frequency of the WDT clock source. The nominal frequency of the clock source is device dependent. The frequency may vary as a function of the device operating voltage and temperature.

The available clock sources for Run mode are device dependent.