When configuring the RTC to use either XOSC32K or the external clock on TOSC1, XOSC32K needs toīe enabled and the Source Select bit (SEL) and Run Standby bit (RUNSTDBY) in the XOSC32K ControlĪ register of the Clock Controller (CLKCTRL.XOSC32KCTRLA) must be configured accordingly. This option is only available for processors with an RTC (XTINY).ģ2KHZ_32KHZ_INTOSC : 32 KHz from OSCULP32Kģ2KHZ_32KHZ_CRYSTOSC : 32 KHz from XOSC32KĮXT_OSC_TOSC1 : External clock from TOSC1 pin. The overflow mode is used and you can use the compare overflow if required.ĭo not forget to enable the 32 KHz oscillator and the interrupts as shown in the Xmega example. The 1KHz clocks will load the PER register with 1000-1 and the 32 KHz clock will load PER with a value of 32768-1. This option is only available for processors with an RTC (XMEGA).ġKHZ_INT32KHZ_ULP 1 kHz from internal 32 kHz ULPġKHZ_32KHZ_CRYSTOSC 1 kHz from 32 kHz Crystal Oscillator on TOSCġKHZ_INT32KHZ_RCOSC 1 kHz from internal 32 kHz RC Oscillatorģ2KHZ_32KHZ_CRYSTOSC 32 kHz from 32 kHz Crystal Oscillator on TOSC This option only works with the SOFT clock mode. The usage of the optional SECTIC routine will use 30 bytes of the hardware stack. It is important that you use the name SECTIC and that you return with a RETURN statement from this label. Since the interrupt occurs every second you may handle various tasks in the sectic label. This option allows to jump to a user routine with the label sectic. Use USER to write/use your own code in combination with an I2C clock chip for example. In general you enable global interrupts after all interrupts are setup.įor the SOFT mode you need to connect a special low frequency crystal with a value of 32768 Hz to the ASYNC TIMER oscillator pins. While the compiler could enable the global interrupt automatic, you would not have control anymore when it is enabled when using multiple interrupts. The timer interrupt is enabled automatic but the global interrupt you need to enable yourself.

You need to add an ENABLE INTERRUPTS statement to your code since the SOFT mode uses the timer in interrupt mode. Use SOFT for using the software based clock routines.

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