20.4.1 Mode of Operation

The primary function of the DMT module is to Reset the processor in the event of a software malfunction. The DMT module, which works on the system clock, is a free running instruction fetch timer that is clocked whenever an instruction fetch occurs until a count match occurs. The instructions are not fetched when the processor is in the Standby Sleep mode.

The DMT module consists of a 32-bit counter, the read-only DMTCNT register with a time-out count match value as specified by the 32-bit DMT count configuration fuse bits CFGCON2.DMTCNT[4:0]. Whenever the count match occurs, a DMT Reset event will occur and the DMTEVENT bit in DMTSTAT register is set.

A DMT module is typically used in mission-critical and safety-critical applications, where any failure of the software functionality and sequencing must be detected.