rtc32_driver.c File Reference

XMEGA 32-bit RTC driver source file. More...

#include "avr_compiler.h"
#include "rtc32_driver.h"

Include dependency graph for rtc32_driver.c:

Go to the source code of this file.

Functions
uint32_t	RTC32_GetCount (void)
	This function returns the current RTC count value.
void	RTC32_Initialize (uint32_t period, uint32_t count, uint32_t compareValue)
	This function initializes the RTC with period, initial count and compare value.
void	RTC32_SetAlarm (uint32_t alarmTimeout)
	This function sets a timeout alarm.
void	RTC32_SetCompareIntLevel (RTC32_COMPINTLVL_t intLevel)
	This function sets the RTC compare interrupt level.
void	RTC32_SetCount (uint32_t count)
	This function sets a new RTC count value.
void	RTC32_SetIntLevels (RTC32_OVFINTLVL_t ovfIntLevel, RTC32_COMPINTLVL_t compIntLevel)
	This function sets both compare and overflow interrupt levels in one go.
void	RTC32_SetOverflowIntLevel (RTC32_OVFINTLVL_t intLevel)
	This function sets the RTC overflow interrupt level.
void	RTC32_SetPeriod (uint32_t period)
	This function sets a new RTC period.

---

Detailed Description

XMEGA 32-bit RTC driver source file.

This file contains the function implementations the XMEGA 32-bit RTC driver.

The driver is not intended for size and/or speed critical code, since most functions are just a few lines of code, and the function call overhead decreases code performance.

Application note:

AVR1010: Minimizing the power consumption of XMEGA devices

Documentation

For comprehensive code documentation, supported compilers, compiler settings and supported devices see readme.html

Author:

Atmel Corporation: http://www.atmel.com
Support email: avr@atmel.com

Revision

5159

Date

2009-06-09 19:05:02 +0200 (ti, 09 jun 2009)

Copyright (c) 2008, Atmel Corporation All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. The name of ATMEL may not be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Definition in file rtc32_driver.c.

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Function Documentation

uint32_t RTC32_GetCount

(

void

)

This function returns the current RTC count value.

This function synchronizes the RTC32 module's CNT value to the system clock domain, then returns its value.

Returns:

The current RTC count value.

Definition at line 185 of file rtc32_driver.c.

References RTC32_SyncCnt, and RTC32_SyncCntBusy.

{
        /* Synchronize the RTC module's CNT value to the system clock domain.  */
        RTC32_SyncCnt();
        do { } while ( RTC32_SyncCntBusy() );
        
        return RTC32.CNT;
}

void RTC32_Initialize	(	uint32_t	period,
		uint32_t	count,
		uint32_t	compareValue
	)

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.

Parameters:

	period	RTC period. Topvalue = Period - 1.
	count	Initial RTC count.
	compareValue	Compare value.

Definition at line 70 of file rtc32_driver.c.

References RTC32_SyncBusy.

Referenced by vbat_init().

{
        /* 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() );
}

void RTC32_SetAlarm

(

uint32_t

alarmTimeout

)

This function sets a timeout alarm.

This function sets a timeout alarm by adding the timeout to the current count value. If the resulting alarm value is larger than the RTC period value, it will wrap around. An RTC compare interrupt will be triggered¨ after the specified timeout.

Note:

The program code needs to check if the RTC is busy before calling this function. The RTC_Busy() function can be used to do this.

The timeout must be less than the timer period. The timeout should not be set too low, as the timeout may be missed, depending on CPU speed.

Parameters:

alarmTimeout

Timeout time in RTC clock cycles (scaled).

Definition at line 139 of file rtc32_driver.c.

References RTC32_SyncCnt, and RTC32_SyncCntBusy.

Referenced by main().

{
        uint32_t compareValue;
        
        /* Synchronize CNT from RTC to system clock domain. */
        RTC32_SyncCnt();
        do { } while ( RTC32_SyncCntBusy() );
        
        /* Calculate compare time. */
        compareValue = RTC32.CNT + alarmTimeout;

        /* Wrap on period. */
        if (compareValue > RTC32.PER){
                compareValue -= RTC32.PER;
        }

        /* Add the timeout value to get the absolute time of the alarm. */
        RTC32.COMP = compareValue;
}

void RTC32_SetCompareIntLevel

(

RTC32_COMPINTLVL_t

intLevel

)

This function sets the RTC compare interrupt level.

Parameters:

intLevel

The compare interrupt level.

Definition at line 103 of file rtc32_driver.c.

Referenced by main(), and vbat_init().

{
        RTC32.INTCTRL = ( RTC32.INTCTRL & ~RTC32_COMPINTLVL_gm ) | intLevel;
}

void RTC32_SetCount

(

uint32_t

count

)

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.
The function does not return until the CNT register has synchronized from the system to RTC clock domain.

Parameters:

count

The new RTC count value.

Definition at line 168 of file rtc32_driver.c.

References RTC32_SyncBusy.

{
        /* 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() );
}

void RTC32_SetIntLevels	(	RTC32_OVFINTLVL_t	ovfIntLevel,
		RTC32_COMPINTLVL_t	compIntLevel
	)

This function sets both compare and overflow interrupt levels in one go.

Parameters:

	ovfIntLevel	The overflow interrupt level.
	compIntLevel	The compare interrupt level.

Definition at line 115 of file rtc32_driver.c.

{
        RTC32.INTCTRL = ( RTC32.INTCTRL &
                        ~( RTC32_COMPINTLVL_gm | RTC32_OVFINTLVL_gm ) ) |
                        ovfIntLevel |
                        compIntLevel;
}

void RTC32_SetOverflowIntLevel

(

RTC32_OVFINTLVL_t

intLevel

)

This function sets the RTC overflow interrupt level.

Parameters:

intLevel

The overflow interrupt level.

Definition at line 93 of file rtc32_driver.c.

{
        RTC32.INTCTRL = ( RTC32.INTCTRL & ~RTC32_OVFINTLVL_gm ) | intLevel;
}

void RTC32_SetPeriod

(

uint32_t

period

)

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.

Parameters:

period

The new RTC period.

Definition at line 201 of file rtc32_driver.c.

References RTC32_SyncBusy.

{
        /* 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() );
}