mirror of
https://github.com/arduino/Arduino.git
synced 2024-11-30 11:24:12 +01:00
133 lines
4.1 KiB
C
133 lines
4.1 KiB
C
/* ----------------------------------------------------------------------------
|
|
* SAM Software Package License
|
|
* ----------------------------------------------------------------------------
|
|
* Copyright (c) 2011-2012, Atmel Corporation
|
|
*
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following condition is met:
|
|
*
|
|
* - Redistributions of source code must retain the above copyright notice,
|
|
* this list of conditions and the disclaimer below.
|
|
*
|
|
* Atmel's name may not be used to endorse or promote products derived from
|
|
* this software without specific prior written permission.
|
|
*
|
|
* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
|
|
* 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.
|
|
* ----------------------------------------------------------------------------
|
|
*/
|
|
|
|
/** \addtogroup rtt_module Working with RTT
|
|
* The RTT driver provides the interface to configure and use the RTT
|
|
* peripheral.
|
|
*
|
|
* The Real-time Timer is used to count elapsed seconds.\n
|
|
* This timer is clocked by the 32kHz system clock divided by a programmable
|
|
* 16-bit balue. To be accurate, it is better to use an
|
|
* external 32kHz crystal instead of the internal 32kHz RC.\n
|
|
*
|
|
* To count elapsed seconds, the user could follow these few steps:
|
|
* <ul>
|
|
* <li>Programming PTPRES in RTT_MR to feeding the timer with a 1Hz signal.</li>
|
|
* <li>Writing the bit RTTRST in RTT_MR to restart the timer with new settings.</li>
|
|
* </ul>
|
|
*
|
|
* An alarm can be set to happen on second by setting alarm value in RTT_AR.
|
|
* Alarm occurence can be detected by polling or interrupt.
|
|
*
|
|
* For more accurate information, please look at the RTT section of the
|
|
* Datasheet.
|
|
*
|
|
* Related files :\n
|
|
* \ref rtt.c\n
|
|
* \ref rtt.h.\n
|
|
*/
|
|
/*@{*/
|
|
/*@}*/
|
|
|
|
/**
|
|
* \file
|
|
*
|
|
* Implementation of Real Time Timer (RTT) controller.
|
|
*
|
|
*/
|
|
|
|
/*----------------------------------------------------------------------------
|
|
* Headers
|
|
*----------------------------------------------------------------------------*/
|
|
#include "chip.h"
|
|
|
|
#include <assert.h>
|
|
|
|
/*----------------------------------------------------------------------------
|
|
* Exported functions
|
|
*----------------------------------------------------------------------------*/
|
|
|
|
/**
|
|
* \brief Changes the prescaler value of the given RTT and restarts it.
|
|
*
|
|
* \note This function disables RTT interrupt sources.
|
|
*
|
|
* \param rtt Pointer to a Rtt instance.
|
|
* \param prescaler Prescaler value for the RTT.
|
|
*/
|
|
void RTT_SetPrescaler(Rtt *rtt, uint16_t prescaler)
|
|
{
|
|
rtt->RTT_MR = (prescaler | RTT_MR_RTTRST);
|
|
}
|
|
|
|
/**
|
|
* \brief Returns the current value of the RTT timer value.
|
|
*
|
|
* \param rtt Pointer to a Rtt instance.
|
|
*/
|
|
uint32_t RTT_GetTime(Rtt *rtt)
|
|
{
|
|
return rtt->RTT_VR;
|
|
}
|
|
|
|
/**
|
|
* \brief Enables the specified RTT interrupt sources.
|
|
*
|
|
* \param rtt Pointer to a Rtt instance.
|
|
* \param sources Bitmask of interrupts to enable.
|
|
*/
|
|
void RTT_EnableIT(Rtt *rtt, uint32_t sources)
|
|
{
|
|
assert( (sources & 0x0004FFFF) == 0 ) ;
|
|
rtt->RTT_MR |= sources;
|
|
}
|
|
|
|
/**
|
|
* \brief Returns the status register value of the given RTT.
|
|
*
|
|
* \param rtt Pointer to an Rtt instance.
|
|
*/
|
|
uint32_t RTT_GetStatus(Rtt *rtt)
|
|
{
|
|
return rtt->RTT_SR;
|
|
}
|
|
|
|
/**
|
|
* \brief Configures the RTT to generate an alarm at the given time.
|
|
*
|
|
* \param pRtt Pointer to an Rtt instance.
|
|
* \param time Alarm time.
|
|
*/
|
|
void RTT_SetAlarm(Rtt *pRtt, uint32_t time)
|
|
{
|
|
assert(time > 0);
|
|
|
|
pRtt->RTT_AR = time - 1;
|
|
}
|