
System window watchdog (WWDG)
RM0453
988/1454
RM0453 Rev 2
31.5.2 WWDG
configuration register (WWDG_CFR)
Address offset: 0x004
Reset value: 0x0000 007F
Bits 31:8 Reserved, must be kept at reset value.
Bit 7
WDGA:
Activation bit
This bit is set by software and only cleared by hardware after a reset. When WDGA = 1, the
watchdog can generate a reset.
0: Watchdog disabled
1: Watchdog enabled
Bits 6:0
T[6:0]:
7-bit counter (MSB to LSB)
These bits contain the value of the watchdog counter, decremented every
(4096 x 2
WDGTB
[2:0]
) PCLK cycles. A reset is produced when it is decremented from 0x40 to
0x3F (T6 becomes cleared).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res.
Res.
WDGTB[2:0]
Res.
EWI
Res.
Res.
W[6:0]
rw
rw
rw
rs
rw
rw
rw
rw
rw
rw
rw
Bits 31:14 Reserved, must be kept at reset value.
Bits 13:11
WDGTB[2:0]:
Timer base
The timebase of the prescaler can be modified as follows:
000: CK counter clock (PCLK div 4096) div 1
001: CK counter clock (PCLK div 4096) div 2
010: CK counter clock (PCLK div 4096) div 4
011: CK counter clock (PCLK div 4096) div 8
100: CK counter clock (PCLK div 4096) div 16
101: CK counter clock (PCLK div 4096) div 32
110: CK counter clock (PCLK div 4096) div 64
111: CK counter clock (PCLK div 4096) div 128
Bit 10 Reserved, must be kept at reset value.
Bit 9
EWI:
Early wakeup interrupt
When set, an interrupt occurs whenever the counter reaches the value 0x40. This interrupt is
only cleared by hardware after a reset.
Bits 8:7 Reserved, must be kept at reset value.
Bits 6:0
W[6:0]:
7-bit window value
These bits contain the window value to be compared with the down-counter.