435
/
838
Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Bit field
Name
Description
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 16-1
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’.
16.5.5
IWDG status register (IWDG_STS)
Address offset: 0x0C
Reset value: 0x00000000
Bit field
Name
Description
31:2
Reserved
Reserved, the reset value must be maintained.
1
CRVU
Watchdog reload value update
Reload Value Update: this bit indicates an update of reload value is ongoing. Set by hardware and
clear by hardware. Software can only try to change IWDG_RELV.REL[11:0] value when
IWDG_KEY.KEYV[15:0] bits’ value is 0x5555 and this bit is 0.
0
PVU
Watchdog pre-scaler value update
Pre-scaler Value Update: this bit indicates an update of pre-scaler value is ongoing. Set by hardware
and clear by hardware. Software can only try to change IWDG_PREDIV.PD[2:0] value when
IWDG_KEY.KEYV[15:0] bits’ value is 0x5555 and this bit is 0.