TC1796
System Units (Vol. 1 of 2)
Watchdog Timer
User’s Manual
16-15
V2.0, 2007-07
WDT, V2.0
16.4.6.3 Disable Mode Details
Disable Mode is provided for applications that truly do not require the WDT function. It
can only be entered from Time-Out Mode if bit WDT_CON1.WDTDR is set to 1 before
proper termination of Time-Out Mode. The counter stops in this mode, eliminating the
need for a WDT service. However, if an access to register WDT_CON0 is performed, the
WDT will leave Disable Mode. Disable Mode does not stop the detection of access errors
and the entry of Prewarning Mode nor the entry of Time-Out Mode on a Valid Password
Access.
Table 16-6
WDT Disable Mode
State /
Action
Description
Entry
•
Only from Time-Out Mode by writing ENDINIT to 1 with a Valid Modify
Access (a Valid Password Access must have been executed first),
while bit WDTDR = 1.
Actions
on Entry
•
Bits WDTAE, WDTOE, WDTPR, and WDTTO are cleared. Bit WDTDS
is set to 1.
•
Timer WDTTIM is stopped (it retains its current value).
Operation
–
Exit
1. Valid Password Access to register WDTCON.
2. Invalid access to WDT_CON0 (either during the password or the Modify
Access).
Next
Mode
Depending on Exit condition:
1. Time-Out Mode.
2. Prewarning Mode, bit WDTAE is set to 1 (access error).