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AT32F413
Series Reference Manual
2022.06.27
Page 255
Rev 2.00
16
Watchdog timer (WDT)
16.1 WDT introduction
The WDT is driven by a dedicated low-speed clock (LICK). Due to the lower clock accuracy of LICK, the
WDT is best suited for the applications that require lower timing accuracy and can run independently
out of the main application.
16.2 WDT main features
12-bit downcounter
The counter is clocked by LICK (can work in Stop and Standby modes)
If the WDT is enabled, a system reset is generated when the counter value reaches 0
16.3 WDT functional overview
WDT enable:
Both software and hardware operations can be used to enable WDT. In other words, the WDT can be
enabled by writing 0xCCCC to the WDT_CMD register; or can be enabled by hardware configuring the
user system area. When the WDT is enabled by hardware, it will automatically run after a power-on reset.
WDT reset conditions:
W
hen the counter value of the WDT counts down to 0, a WDT reset is generated. Thus the WDT_CMD
register must be written with the value 0xAAAA at regular intervals to reload the counter value to avoid
the WDT reset.
WDT write-protected:
The WDT_DIV and WDT_RLD registers are write-protected. Writing the value 0x5555 to the WDT_CMD
register will unlock write protection. The update status of these two registers are indicated by the DIVF
and RLDF bits in the WDT_STS register respectively. If a different value is written to the WDT_CMD
register, these two registers will be re-protected. Writing the value 0xAAAA to the WDT_CMD register
also enables write protection.
WDT clock:
The WDT counter is clocked by the LICK. The LICK is an internal RC clock with a certain range of
timeout period. Thus a margin should be taken into account when configuring timeout period. The
LICK can be calibrated to obtain the WDT timeout with a relatively accuracy. For more details, please
refer to
Section 4.1.1