Reset and clock control for STM32F405xx/07xx and STM32F415xx/17xx(RCC)
RM0090
262/1731
DocID018909 Rev 11
7.3.22
RCC clock control & status register (RCC_CSR)
Address offset: 0x74
Reset value: 0x0E00 0000, reset by system reset, except reset flags by power reset only.
Access: 0
≤
wait state
≤
3, word, half-word and byte access
Wait states are inserted in case of successive accesses to this register.
Bit 2
LSEBYP:
External low-speed oscillator bypass
Set and cleared by software to bypass the oscillator. This bit can be written only when the
LSE clock is disabled.
0: LSE oscillator not bypassed
1: LSE oscillator bypassed
Bit 1
LSERDY:
External low-speed oscillator ready
Set and cleared by hardware to indicate when the external 32 kHz oscillator is stable. After
the LSEON bit is cleared, LSERDY goes low after 6 external low-speed oscillator clock
cycles.
0: LSE clock not ready
1: LSE clock ready
Bit 0
LSEON:
External low-speed oscillator enable
Set and cleared by software.
0: LSE clock OFF
1: LSE clock ON
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
LPWR
RSTF
WWDG
RSTF
IWDG
RSTF
SFT
RSTF
POR
RSTF
PIN
RSTF
BORRS
TF
RMVF
Reserved
r
r
r
r
r
r
r
rt_w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
LSIRDY LSION
r
rw
Bit 31
LPWRRSTF:
Low-power reset flag
Set by hardware when a Low-power management reset occurs.
Cleared by writing to the RMVF bit.
0: No Low-power management reset occurred
1: Low-power management reset occurred
For further information on Low-power management reset, refer to
.
Bit 30
WWDGRSTF:
Window watchdog reset flag
Set by hardware when a window watchdog reset occurs.
Cleared by writing to the RMVF bit.
0: No window watchdog reset occurred
1: Window watchdog reset occurred
Bit 29
IWDGRSTF
: Independent watchdog reset flag
Set by hardware when an independent watchdog reset from V
DD
domain occurs.
Cleared by writing to the RMVF bit.
0: No watchdog reset occurred
1: Watchdog reset occurred