Xmega Application Note | |||||
This file contains the function implementations the XMEGA 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 would decrease code performance. The driver is intended for rapid prototyping and documentation purposes for getting started with the XMEGA RTC module.
For size and/or speed critical code, it is recommended to copy the function contents directly into your application instead of making a function call.
Copyright (c) 2008, Atmel Corporation All rights reserved.
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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.
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Definition in file rtc_driver.c.
#include "rtc_driver.h"
Go to the source code of this file.
Functions | |
void | RTC_Initialize (uint16_t period, uint16_t count, uint16_t compareValue, RTC_PRESCALER_t prescaler) |
This function initializes the RTC with period, initial count, compare value and clock prescaler. | |
void | RTC_SetAlarm (uint16_t alarmTimeout) |
This function sets a timeout alarm. | |
void | RTC_SetCompareIntLevel (RTC_COMPINTLVL_t intLevel) |
This function sets the RTC compare interrupt level. | |
void | RTC_SetIntLevels (RTC_OVFINTLVL_t ovfIntLevel, RTC_COMPINTLVL_t compIntLevel) |
This function sets both compare and overflow interrupt levels in one go. | |
void | RTC_SetOverflowIntLevel (RTC_OVFINTLVL_t intLevel) |
This function sets the RTC overflow interrupt level. | |
void | RTC_SetPrescaler (RTC_PRESCALER_t prescaler) |
This function sets a new RTC clock prescaler value. |
void RTC_Initialize | ( | uint16_t | period, | |
uint16_t | count, | |||
uint16_t | compareValue, | |||
RTC_PRESCALER_t | prescaler | |||
) |
This function initializes the RTC with period, initial count, compare value and clock prescaler.
All the synchronized registers are written at the same time to save time. The program code need to check if the RTC is busy before calling this function. The RTC_Busy() function can be used to do this.
period | RTC period. Topvalue = Period - 1. | |
count | Initial RTC count. | |
compareValue | Compare value. | |
prescaler | Clock prescaler setting. |
Definition at line 75 of file rtc_driver.c.
Referenced by main().
00079 { 00080 RTC.PER = period - 1; 00081 RTC.CNT = count; 00082 RTC.COMP = compareValue; 00083 RTC.CTRL = ( RTC.CTRL & ~RTC_PRESCALER_gm ) | prescaler; 00084 }
void RTC_SetAlarm | ( | uint16_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.
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.
alarmTimeout | Timeout time in RTC clock cycles (scaled). |
Definition at line 138 of file rtc_driver.c.
00139 { 00140 /* Calculate compare time. */ 00141 uint16_t compareValue = RTC.CNT + alarmTimeout; 00142 00143 /* Wrap on period. */ 00144 if (compareValue > RTC.PER){ 00145 compareValue -= RTC.PER; 00146 } 00147 00148 /* Add the timeout value to get the absolute time of the alarm. */ 00149 RTC.COMP = compareValue; 00150 }
void RTC_SetCompareIntLevel | ( | RTC_COMPINTLVL_t | intLevel | ) |
This function sets the RTC compare interrupt level.
intLevel | The compare interrupt level. |
Definition at line 101 of file rtc_driver.c.
void RTC_SetIntLevels | ( | RTC_OVFINTLVL_t | ovfIntLevel, | |
RTC_COMPINTLVL_t | compIntLevel | |||
) |
This function sets both compare and overflow interrupt levels in one go.
ovfIntLevel | The overflow interrupt level. | |
compIntLevel | The compare interrupt level. |
Definition at line 113 of file rtc_driver.c.
Referenced by main().
00115 { 00116 RTC.INTCTRL = ( RTC.INTCTRL & 00117 ~( RTC_COMPINTLVL_gm | RTC_OVFINTLVL_gm ) ) | 00118 ovfIntLevel | 00119 compIntLevel; 00120 }
void RTC_SetOverflowIntLevel | ( | RTC_OVFINTLVL_t | intLevel | ) |
This function sets the RTC overflow interrupt level.
intLevel | The overflow interrupt level. |
Definition at line 91 of file rtc_driver.c.
void RTC_SetPrescaler | ( | RTC_PRESCALER_t | prescaler | ) |
This function sets a new RTC clock prescaler value.
prescaler | Clock prescaler setting. |
Definition at line 160 of file rtc_driver.c.
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