RM0090: Reference manual - STMicroelectronics

Reset and clock control for (RCC) RM0090
6 Reset and clock control for (RCC)
6.1 Reset
There are three types of reset, defined as system Reset, power Reset and backup domain
Reset.
6.1.1 System reset
A system reset sets all registers to their reset values except the reset flags in the clock
controller CSR register and the registers in the Backup domain (see Figure 4).
A system reset is generated when one of the following events occurs:
1. A low level on the NRST pin (external reset)
2. Window watchdog end of count condition (WWDG reset)
3. Independent watchdog end of count condition (IWDG reset)
4. A software reset (SW reset) (see Software reset)
5. Low-power management reset (see Low-power management reset)
Software reset
The reset source can be identified by checking the reset flags in the RCC clock control &
status register (RCC_CSR).
The SYSRESETREQ bit in Cortex-M4F Application Interrupt and Reset Control Register
must be set to force a software reset on the device. Refer to the Cortex-M4F technical
reference manual for more details.
111/1416 Doc ID 018909 Rev 3