Posted on May 17, 2011 at 11:55 The documentation about the watchdog timer is very inaccurate and completely misleading.
1 - The watchdog timer is a down counter: it decrements once at every machine cycle, and overflows from 0 to 3FFFFFH (unless reset before).
2 - The value written in the WDRST register is indeed loaded into the 7 MSB of the timer: the greater this value, the longer the period.
3 - The WDRST value may range from 1 (minimum) to 7F (maximum). A value of 0 STOPS the timer.
4 - For some misterious reason, writing to the PCON register resets the watchdog timer to its maximum value (7F).
