GD32F20x User Manual
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16.2.
Window watchdog timer (WWDGT)
16.2.1.
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 or refreshes before the counter reaches the window value.
Interrupt occurs if it is enabled.
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.
16.2.2.
Charateristics
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): if the watchdog is started and the interrupt is enabled, the
interrupt occurs when the counter reaches 0x40 or refreshes before it reaches the
window value.
WWDGT debug mode, the WWDGT can stop or continue to work in debug mode.
16.2.3.
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.
Summary of Contents for GD32F20 Series
Page 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Page 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Page 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Page 385: ...GD32F20x User Manual 385 ...
Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...