3.1.14.2.5 TC_MIN_COUNT_BEFORE_ERROR

#define TC_MIN_COUNT_BEFORE_ERROR (5U)

This is a macro for Minimum value of TMR0 overflows before WDT is allowed to reset device ~5ms Taking the frequency tolerance into account. WDT Timeout is 8ms - ~35% frequency tolerance of clock TC_MIN_COUNT_BEFORE_ERROR = = 8ms - 35% tolerance = 8ms - 2.8 = 5.2ms ~ 5ms