Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
350
/
631
Bit field
Name
Description
2:0
PD[2:0]
Pre-frequency division factor
Pre-scaler divider: with write access protection when IWDG_KEY.KEYV[15:0] is not 0x5555. The
IWDG_STS.PVU bit must be 0 otherwise PD [2:0] value cannot be changed. Divide number is as
follow:
000: divider /4
001: divider /8
010: divider /16
011: divider /32
100: divider /64
101: divider /128
Other : divider /256
Note: Reading this register will return the pre-divided value from the VDD voltage domain. If a write
operation is in progress, the read-back value may be invalid. Therefore, the read value is valid only
when the IWDG_STS.PVU bit is ‘0’.
IWDG reload register (IWDG_RELV)
Address offset: 0x08
Reset value: 0x00000FFF
Bit field
Name
Description
31:12
Reserved
Reserved, the reset value must be maintained.
11:0
REL[11:0]
Watchdog counter reload value.
With write protection. Defines the reload value of the watchdog counter, which is loaded to the
counter every time 0xAAAA is written to IWDG_KEY.KEYV[15:0] bits. The counter then starts to
count down from this value. The watchdog timeout period can be calculated from this reloading value
and the clock pre-scaler value, refer to Table 15-1.
This register can only be modified when the IWDG_STS.CRVU bit is ‘0’.
Note: Reading this register will return the reload value from the VDD voltage domain. If a write
operation is in progress, the read-back value may be invalid. Therefore, the read value is valid only
when the IWDG_STS.CRVU bit is ‘0’.
IWDG status register (IWDG_STS)
Address offset: 0x0C