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GD32E23x User Manual
196
Figure 12-3. Window watchdog timing diagram
Write WWDG_CTL when CTN>WIN
cause a reset
CNT[6]=0 cause a reset
0x7F
Start
CNT[6:0]
0x3F
WIN
Write CNT
Start
Calculate the WWDGT timeout by using the formula below.
t
WWDGT
= t
PCLK1
× 4096 × 2
𝑃𝑆𝐶
× ( 𝐶𝑁𝑇[5: 0] + 1) (𝑚𝑠)
(12-1)
where:
t
WWDGT
: WWDGT timeout
t
PCLK1
: APB1 clock period measured in ms
The table below shows the minimum and maximum values of the t
WWDGT
.
Table 12-2. Min-max timeout value at 72 MHz (f
PCLK1
)
Prescaler divider
PSC[1:0]
Min timeout value
CNT[6:0] =0x40
Max timeout value
CNT[6:0]=0x7F
1/1
00
56 μs
3.64 ms
1/2
01
113 μs
7.28 ms
1/4
10
227 μs
14.56 ms
1/8
11
455 μs
29.12 ms
If the WWDGT_HOLD bit in DBG module is cleared, the WWDGT continues to work even
the Cortex
®
-M23 core halted (Debug mode). While the WWDGT_HOLD bit is set, the
WWDGT stops in Debug mode.