AT32F421
Series Reference Manual
2022.11.11
Page 288
Rev 2.02
Table 15-1 Minimum and maximum timeout value when PCLK1=72 MHz
Prescaler
Min. Timeout value
Max. Timeout value
0
56.5μs
3.64ms
1
113.5μs
7.28ms
2
227.5μs
14.56ms
3
455μs
29.12ms
Figure 15-2 Window watchdog timing diagram
...
55
54
53
52
51
50
4F 4E
4D 4C
4B
4A
...
41
40
3F
55
CNT[6
:
0]
4F
WIN[6
:
0]
55
RLD[6
:
0]
Refresh not allowed
Refresh the window
CNT[6]
Reset
15.4 Debug mode
When the microcontroller enters debug mode (Cortex
TM
-M4 core halted), the WWDT counter stops
counting by setting the WWDT_PAUSE in the DEBUG module.
15.5 WWDT registers
These peripheral registers must be accessed by word (32 bits).
Table 15-2 WWDT register map and reset value
Register name
Offset
Reset value
WWDT_CTRL
0x00
0x7F
WWDT_CFG
0x04
0x7F
WWDT_STS
0x08
0x00
15.5.1 Control register (WWDT_CTRL)
Bit
Register
Reset value
Type
Description
Bit 31: 8
Reserved
0x000000
resd
Kept at its default value.
Bit 7
WWDTEN
0x0
rw1s
Window watchdog enable
0: Disabled
1: Enabled
This bit is set by software, but can be cleared only after
reset.
Bit 6: 0
CNT
0x7F
rw
Downcounter
When the counter counts down to 0x3F, a reset is
generated.