GD32F3x0 User Manual
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14.2. Window watchdog timer (WWDGT)
14.2.1. Overview
The window watchdog timer (WWDGT) is used to detect system failures due to software
malfunctions. After the window watchdog timer starts, the value of downcounter reduces
progressively. The watchdog timer causes a reset when the counter reached 0x3F (the
CNT[6] bit becomes cleared). The watchdog timer also causes a reset if the counter is
refreshed before the counter reached the window register value. So the software should
refresh the counter in a limited window. The window watchdog timer generates an early
wakeup status flag when the counter reaches 0x40. Interrup occurs if it is enable.
The window watchdog timer clock is prescaled from the APB1 clock. The window watchdog
timer is suitable for the situation that requires an accurate timing.
14.2.2. Characteristics
Programmable free-running 7-bit downcounter.
Generate reset in two conditions when WWDGT is enabled:
– Reset when the counter reached 0x3F
– The counter is refreshed when the value of the counter is greater than the window
register value
Early wakeup interrupt (EWI): the watchdog is started and the interrupt is enabled, the
interrupt occurs when the counter reaches 0x40.
WWDGT debug mode, the WWDGT can stop or continue to work in debug mode.
14.2.3. Function overview
If the window watchdog timer is enabled (set the WDGTEN bit in the WWDGT_CTL), the
watchdog timer cause a reset when the counter reaches 0x3F (the CNT[6] bit becomes
cleared), or when the counter is refreshed before the counter reaches the window register
value.
Figure 14-2. Window watchdog timer block diagram
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