DocID024597 Rev 3 1051/1693
RM0351 Independent watchdog (IWDG)
1055
32.4.2 Prescaler register (IWDG_PR)
Address offset: 0x04
Reset value: 0x0000 0000
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.
1514131211109876543210
Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. PR[2:0]
rw rw rw
Bits 31:3 Reserved, must be kept at reset value.
Bits 2:0 PR[2:0]: Prescaler divider
These bits are write access protected see Section 32.3.6: Register access protection. They are
written by software to select the prescaler divider feeding the counter clock. PVU bit of
IWDG_SR must be reset in order to be able to change the prescaler divider.
000: divider /4
001: divider /8
010: divider /16
011: divider /32
100: divider /64
101: divider /128
110: divider /256
111: divider /256
Note: Reading this register returns the prescaler value from the VDD voltage domain. This
value may not be up to date/valid if a write operation to this register is ongoing. For this
reason the value read from this register is valid only when the PVU bit in the IWDG_SR
register is reset.