![Geehy SEMICONDUCTOR APM32F405 Series User Manual Download Page 269](http://html1.mh-extra.com/html/geehy-semiconductor/apm32f405-series/apm32f405-series_user-manual_573630269.webp)
www.geehy.com Page 268
Figure 67 Window Watchdog Timing Diagram
Counter
Window
value
0x3F
Reload
counter
Generate
reset
Counter
Window
value
Reload counter
Generate reset
CNT>window value
Start
Start
The calculation formula of window watchdog timer timeout is as follows:
T
WWDT
=T
PCLK1
×2
WTB
×
(
T[5:0]+1
)
Wherein:
T
WWDT
: WWDT timeout
T
PCLK1
: Clock cycle of APB1 (in ms)
Minimum/Maximum timeout when PCLK1=36MHZ:
Table 76 Min/Max Timeout when PCLK1=36MHz
WTB
Min timeout value
Max timeout value
0
136.53μs
8.74ms
1
273.07μs
17.48ms
2
546.13μs
34.95ms
3
1092.27μs
69.91ms
IWDT register address mappin
Table 77 IWDT Register Address Mapping
Register name
Description
Offset address
IWDT_KEY
Key register
0x00
IWDT_PSC
Prescaler register
0x04
IWDT_CNTRLD
Counter reload register
0x08
IWDT_STS
State register
0x0C