RTC32 mit XMEGA

#include <avr/io.h>

#include <util/atomic.h>

#include <util/delay.h>

#include <avr/interrupt.h>

#include "avr_compiler.h"

/*! \brief CCP write helper function written in assembly.

 *

 *  This function is written in assembly because of the timecritial

 *  operation of writing to the registers.

 *

 *  \param address A pointer to the address to write to.

 *  \param value   The value to put in to the register.

 */

void CCPWrite( volatile uint8_t * address, uint8_t value )

{

  volatile uint8_t * tmpAddr = address;

    ATOMIC_BLOCK(ATOMIC_RESTORESTATE)

    {

#ifdef RAMPZ 

        RAMPZ = 0; 

#endif

        asm volatile(

        "movw r30,  %0"        "\n\t"

        "ldi  r16,  %2"        "\n\t"

        "out   %3, r16"        "\n\t"

        "st     Z,  %1"       "\n\t"

        :

        : "r" (tmpAddr), "r" (value), "M" (CCP_IOREG_gc), "i" (&CCP)

        : "r16", "r30", "r31"

        );

    }

}

/**

 * \internal

 * \brief Check if RTC32 is busy synchronizing

 *

 * \retval true  Is busy

 * \retval false Is ready

 */

uint8_t rtc32_is_busy(void)

{

  return RTC32.SYNCCTRL & RTC32_SYNCBUSY_bm;

}

ISR(RTC32_OVF_vect)

{

    /* Toggle status led */

    PORTR.DIRTGL = PIN0_bm;

}

int main(void)

{

    /* Apply a resetr of the VBAT */

    VBAT.CTRL |= VBAT_ACCEN_bm;

    /* Set access enable bit */

    CCPWrite((void *)&VBAT.CTRL, VBAT_RESET_bm);

    /* Enable 32.768kHz crystal oscillator */

    VBAT.CTRL |= VBAT_XOSCEN_bm | VBAT_XOSCSEL_bm;

    /* Wait until oscillator is stable */

    while(!(VBAT.STATUS & VBAT_XOSCRDY_bm));

    /* Enable low power mode for external oscillator */

    OSC.XOSCCTRL = OSC_X32KLPM_bm;

    /* Reset RTC32 module */

    RTC32.CTRL = 0;

    /* Wait until sync done */

    while(rtc32_is_busy());

    /* Set PER to 1024. CLK source of the RTC32 is 1024 ticks / second = 1 Hz */

    RTC32.PER = 1024;

    /* Reset CNT register */

    RTC32.CNT = 0;

    /* Wait until sync done */

    while(rtc32_is_busy());

    /* Enable overflow interrupts */

    RTC32.INTCTRL = RTC32_OVFINTLVL_MED_gc;

    /* Enable real time module */

    RTC32.CTRL = RTC32_ENABLE_bm;

    /* Wait until sync done */

    while(rtc32_is_busy());

    /* Set port C pin 7 as output */

    PORTC.DIRSET = PIN7_bm;

    /* Enable medium priority interrupts */

    PMIC.CTRL = PMIC_MEDLVLEN_bm;

    /* Set sleep mode and enable sleep */

    SLEEP.CTRL = SLEEP_SMODE_PSAVE_gc | SLEEP_SEN_bm;    

    /* Enable global interrupts */

    sei();

    while(1)

    {

        /* Go sleeping */

        asm("sleep");

    }

}