/*! \brief This function sets a new RTC count value.
*
* This function waits for the RTC32 module to finish synchronizing the CNT
* and CTRL registers before writing the new count.\n
* The function does not return until the CNT register has synchronized from
* the system to RTC clock domain.
*
* \param count The new RTC count value.
*/
void RTC32_SetCount( uint32_t count )
{
/* Make sure that CNT is not currently synchronizing, or write will fail. */
do { } while ( RTC32_SyncBusy() );
/* Write new count value and wait for synchronization before returning. */
RTC32.CNT = count;
do { } while ( RTC32_SyncBusy() );
}
/*! \brief This function sets a new RTC period.
*
* This function disables the RTC32 module, writes the new period to its PER
* register, then re-enables the module.\n
*
* \param period The new RTC period.
*/
void RTC32_SetPeriod( uint32_t period )
{
/* Disable the RTC32 module before writing to it. Wait for synch. */
RTC32.CTRL &= ~RTC32_ENABLE_bm;
do { } while ( RTC32_SyncBusy() );
RTC32.PER = period;
/* Enable the RTC32 module. Wait for synch. */
RTC32.CTRL |= RTC32_ENABLE_bm;
do { } while ( RTC32_SyncBusy() );
}
/*! \brief This function initializes the RTC with period, initial count and
* compare value.
*
* All the synchronized registers are written at the same time to save time.
*
* \param period RTC period. Topvalue = Period - 1.
* \param count Initial RTC count.
* \param compareValue Compare value.
*/
void RTC32_Initialize( uint32_t period,
uint32_t count,
uint32_t compareValue )
{
/* Disable the RTC32 module before writing to it. Wait for synch. */
RTC32.CTRL &= ~RTC32_ENABLE_bm;
do { } while ( RTC32_SyncBusy() );
/* Write PER, COMP and CNT. */
RTC32.PER = period - 1;
RTC32.COMP = compareValue;
RTC32.CNT = count;
/* Re-enable the RTC32 module, synchronize before returning. */
RTC32.CTRL |= RTC32_ENABLE_bm;
do { } while ( RTC32_SyncBusy() );
}
static void RTC32_Initialize( uint32_t period,uint32_t count,uint32_t compareValue )
{
// Enable R/W access to the battery backup module.
VBAT.CTRL = VBAT_ACCEN_bm;
// Reset the module. (Reset bit is protected by CCP.)
{uint8_t flags = cpu_irq_save();
CCP = 0xD8;
VBAT.CTRL = VBAT_RESET_bm;
cpu_irq_restore(flags);}
// Enable the failure detection.
VBAT.CTRL |= VBAT_XOSCFDEN_bm;
/* A delay is needed to give the voltage in the backup system some time
* to stabilise.
*/
delay_us(200);
VBAT.CTRL |= VBAT_XOSCEN_bm | VBAT_XOSCSEL_bm;
/* Disable the RTC32 module before writing to it. Wait for synch. */
RTC32.CTRL &= ~RTC32_ENABLE_bm;
do { } while ( RTC32_SyncBusy() );
/* Write PER, COMP and CNT. */
RTC32.PER = period - 1;
RTC32.COMP = compareValue;
RTC32.CNT = count;
/* Re-enable the RTC32 module, synchronize before returning. */
RTC32.CTRL |= RTC32_ENABLE_bm;
do { } while ( RTC32_SyncBusy() );
}
