SAMV71 Xplained Ultra Software Package 1.5

clock-arch.c

00001 /* ----------------------------------------------------------------------------
00002  *         SAM Software Package License 
00003  * ----------------------------------------------------------------------------
00004  * Copyright (c) 2013, Atmel Corporation
00005  *
00006  * All rights reserved.
00007  *
00008  * Redistribution and use in source and binary forms, with or without
00009  * modification, are permitted provided that the following conditions are met:
00010  *
00011  * - Redistributions of source code must retain the above copyright notice,
00012  * this list of conditions and the disclaimer below.
00013  *
00014  * Atmel's name may not be used to endorse or promote products derived from
00015  * this software without specific prior written permission.
00016  *
00017  * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
00018  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00019  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
00020  * DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
00021  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
00022  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
00023  * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00024  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00025  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
00026  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00027  * ----------------------------------------------------------------------------
00028  */
00029 
00030 
00031 /*----------------------------------------------------------------------------
00032  *        Headers
00033  *----------------------------------------------------------------------------*/
00034 
00035 #include "board.h"
00036 #include "clock-arch.h"
00037 
00038 /*----------------------------------------------------------------------------
00039  *        Variables
00040  *----------------------------------------------------------------------------*/
00041 
00042 /** clock tick count */
00043 static volatile uint32_t dwClockTick;
00044 /*----------------------------------------------------------------------------
00045  *        Exported functions
00046  *----------------------------------------------------------------------------*/
00047 void clock_init(void);
00048 clock_time_t clock_time( void );
00049 
00050 /**
00051  *  Interrupt handler for TC0 interrupt.
00052  */
00053 void TC0_Handler( void )
00054 {
00055     volatile uint32_t dwDummy ;
00056 
00057     /* Clear status bit to acknowledge interrupt */
00058     dwDummy = TC0->TC_CHANNEL[0].TC_SR ;
00059 
00060     /* Increase tick */
00061     dwClockTick ++;
00062 }
00063 
00064 
00065 /**
00066  * Initialize for timing operation
00067  */
00068 void clock_init(void)
00069 {
00070     uint32_t div;
00071     uint32_t tcclks;
00072 
00073     /* Clear tick value */
00074     dwClockTick = 0;
00075 
00076     /* Enable peripheral clock. */
00077     PMC_EnablePeripheral( ID_TC0 ) ;
00078 
00079     /* Configure TC for a CLOCK_CONF_SECOND frequency. */
00080     TC_FindMckDivisor( CLOCK_CONF_SECOND, BOARD_MCK, &div, &tcclks, BOARD_MCK ) ;
00081     TC_Configure( TC0, 0, tcclks | TC_CMR_CPCTRG ) ;
00082     TC0->TC_CHANNEL[0].TC_RC = BOARD_MCK / (CLOCK_CONF_SECOND * div);
00083 
00084     /* Configure and enable interrupt on RC compare */    
00085     NVIC_ClearPendingIRQ(TC0_IRQn);
00086     NVIC_EnableIRQ(TC0_IRQn);
00087     
00088     TC0->TC_CHANNEL[ 0 ].TC_IER = TC_IER_CPCS ;
00089 
00090     /* Start timer */
00091     TC_Start( TC0, 0 ) ;
00092 
00093 }
00094 
00095 /**
00096  * Read for clock time (ms)
00097  */
00098 clock_time_t clock_time( void )
00099 {
00100     return dwClockTick;
00101 }
00102 
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