The RTC function in the NUC505 needs to be enabled by RTC_WAKEUP. When the system is powered on, RTC_nRWAKE needs to be grounded so that the RTC function can be enabled. After power on, if the RTC_nRWAKE pin continues low for a period of time (set by the RTC_POWCTL register), the system hardware will automatically shut down. After shut down, the RTC_nRWAKE pin must be powered on or powered down again before the system is restarted. If you do not want the system to shut down, before shut down use the function call RTC_DisableHardwarePowerOff () to disable the RTC power-down function.
Execute the RTC demo code in NuTiny-EVB-NUC505_QFN88 as follows:
Through ICE, before executing the demo code, press the RTC Wake-up key until the demo code is executed;
With the SPI Boot (ICE powered), press the RTC Wake-up key after power on, and then press the Reset key while releasing the Reset and RTC Wake-up keys.
With the SPI Boot, press the RTC Wake-up key and then release the RTC Wake-up key after power on