pues el WWDT es como el WDT, pero no solo resetea el micro si tarda mas de la cuenta, si tarda menos de lo normal, tambien lo resetea, de esta forma si el programa se sale de unos limites superiores o inferiores de tiempo se resetea.
en cuando a WDT y DMT tenemos:
DMT:The primary function of the Deadman Timer (DMT) is to reset the processor in the event of a software malfunction. The DMT is a free-running instruction fetch timer, which is clocked whenever an instruction fetch occurs until a count match occurs. Instructions are not fetched when the processor is in Sleep mode.
The DMT consists of a 32-bit counter with a time-out count match value as specified by the DMTCNT<3:0> bits in the DEVCFG1 Configuration register.
A Deadman Timer is typically used in mission critical and safety critical applications, where any single failure of the software functionality and sequencing must be detected.
y para WDT:
When enabled, the Watchdog Timer (WDT) operates from the internal Low-Power Oscillator (LPRC) clock source and can be used to detect system software malfunctions by resetting the device if the WDT is not cleared periodically in software. Various WDT time-out periods can be selected using the WDT postscaler. The WDT can also be used to wake the device from Sleep or Idle mode.
Some of the key features of the WDT module are:
•Configuration or software controlled
•User-configurable time-out period
•Can wake the device from Sleep or Idle
Sus usos son parecidos, pero el WDT se utiliza para una seguridad mayor, pudiendo contar incluso las instrucciones de programa, se usa mas que nada para seguridad critica.