Watchdog Timer
UG0331 User Guide Revision 15.0
632
The following figure shows how the value of the watchdog timer counter might vary with time.
Figure 269 •
Watchdog Timer Counter
When the TIMEOUT occurs, the watchdog timer counter is reloaded with the WDOGLOAD value. Hence
the WDOGLOAD from the system registers block should be programmed such that it should not be
lesser than the default value of 0x1800000. This is because if the WDOGLOAD is programmed to a
smaller value, each time the WDOGTIMEOUT occurs, the watchdog timer counter is assigned to a lesser
value that results in the counter reaching the timeout value within a short period of time and generating
the TIMEOUT repeatedly. To avoid such instances, the firmware programs the WDOGLOAD value in the
system register to be higher or equal to the default value, which is 0x1800000.
20.2.3.2 Watchdog Timer Behavior During Microcontroller Modes, Device
Programming, and Flash*Freeze
This section describes the behavior of the watchdog timer in the Cortex-M3 processor modes and when
the device is being programmed.
20.2.3.2.1 Cortex-M3 Processor in Debug State
The halted output from the Cortex-M3 is asserted when the processor is in debug mode and this signal is
fed to the Watchdog. When the halted signal is asserted, the watchdog timer counter is halted. This
ensures that the watchdog timer timeout-related resets or interrupts do not occur when a system debug
session is in progress.
Refresh of counter not
Calendar Counter Description
Calendar Counter Description
Calendar Counter Description
Calendar Counter Description
Calendar Counter Description
allowed while counter
value is in this region
Refresh of counter
permitted while counter
value is in this region
WDOGLOAD
WDOGMVRP
counter
value
time
Reset interrupt
generated due to
counter timeout
Reset interrupt
generated due to
counter refresh in
forbidden window
Counter refresh