33.4.4 Watchdog Timer Window
The Watchdog Timer has an optional Windowed mode that enables the WINDIS = 0 bit (WDTCON[0]). In
the Windowed mode (WINDIS= 0
), the WDT must be cleared only within the
allowed window interval of the Watchdog time-out period, as shown in Figure 33-2. There is also an option to select a WDT
window where the WDT should be cleared based on the Watchdog Window Select bits
(WINSIZE[1:0]) in the WDTCON register. The bit settings are as follows:
11
= WDT Allowed Window is 25% of the WDT period.10
= WDT Allowed Window is 37.5% of the WDT period.01
= WDT Allowed Window is 50% of the WDT period.00
= WDT Allowed Window is 75% of the WDT period.
If the Watchdog Timer is cleared before the allowed window, a system Reset is generated immediately.
The Windowed mode is useful for resetting the device during unexpectedly quick or slow execution of a critical portion of the code.
Where:
N1 = 32
N2 = Postscaler divider ratio (see Table 33-2)
TCLK = WDT clock source