On 29-08-2009 at 22:10, Anonymous wrote:
The RTC core and clock configuration (RCC_BDCR register) are in the Backup domain, which means that RTC setting and time are kept after reset or wakeup from Standby mode.
After a power reset has occurred or The MCU has just woken up from Standby mode or Stop mode, access to the Backup registers and RTC is disabled and the Backup domain(BKP) is protected against possible parasitic write access
To enable access to the Backup registers and the RTC, proceed as follows:
1) Enable the power and backup interface clocks by setting the PWREN and BKPEN bits in the RCC_APB1ENR register
2) Set the DBP bit the Power Control Register (PWR_CR) to enable access to the Backup registers and RTC.
For more details refer to RM0008 , Sub-section "Reading RTC registers"
Hope this helps you.
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