SAMV71 Xplained Ultra Software Package 1.4

sys_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  *        Headers
00032  *----------------------------------------------------------------------------*/
00033 
00034 #include "board.h"
00035 #include "sys_arch.h"
00036 
00037 /*----------------------------------------------------------------------------
00038  *        Variables
00039  *----------------------------------------------------------------------------*/
00040 
00041 /** clock tick count */
00042 static volatile uint32_t dwClockTick;
00043 
00044 /*----------------------------------------------------------------------------
00045  *        Exported functions
00046  *----------------------------------------------------------------------------*/
00047 
00048 /**
00049  *  Interrupt handler for TC0 interrupt.
00050  */
00051 void TC0_Handler( void )
00052 {
00053     volatile uint32_t dwDummy ;  
00054     /* Clear status bit to acknowledge interrupt */
00055     dwDummy = TC0->TC_CHANNEL[0].TC_SR ;
00056 
00057     /* Increase tick */
00058     dwClockTick ++;
00059 }
00060 
00061 
00062 /**
00063  * Initialize for timing operation
00064  */
00065 void sys_init_timing(void)
00066 {
00067     uint32_t div;
00068     uint32_t tcclks;
00069 
00070     /* Clear tick value */
00071     dwClockTick = 0;
00072 
00073     /* Enable peripheral clock. */
00074     PMC_EnablePeripheral( ID_TC0 ) ;
00075 
00076     /* Configure TC for a CLOCK_CONF_SECOND frequency. */
00077     TC_FindMckDivisor( CLOCK_CONF_SECOND, BOARD_MCK, &div, &tcclks, BOARD_MCK );
00078     TC_Configure( TC0, 0, tcclks | TC_CMR_CPCTRG );
00079     TC0->TC_CHANNEL[0].TC_RC = BOARD_MCK / (CLOCK_CONF_SECOND * div);
00080 
00081      /* Configure and enable interrupt on RC compare */    
00082     NVIC_ClearPendingIRQ(TC0_IRQn);
00083     NVIC_EnableIRQ(TC0_IRQn);
00084     
00085     TC0->TC_CHANNEL[ 0 ].TC_IER = TC_IER_CPCS ;
00086     /* Start timer */
00087     TC_Start( TC0, 0 );
00088 }
00089 
00090 /**
00091  * Read for clock time (ms)
00092  */
00093 unsigned int sys_get_ms(void)
00094 {
00095     return dwClockTick;
00096 }
00097 
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