120 lines
5.0 KiB
C
120 lines
5.0 KiB
C
/****************************************************************************************
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| Description: Timer driver source file
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| File Name: timer.c
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|----------------------------------------------------------------------------------------
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| C O P Y R I G H T
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|----------------------------------------------------------------------------------------
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| Copyright (c) 2011 by Feaser http://www.feaser.com All rights reserved
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|----------------------------------------------------------------------------------------
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| L I C E N S E
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| This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
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| modify it under the terms of the GNU General Public License as published by the Free
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| Software Foundation, either version 3 of the License, or (at your option) any later
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| version.
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| OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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| without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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| PURPOSE. See the GNU General Public License for more details.
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| You should have received a copy of the GNU General Public License along with OpenBLT.
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| If not, see <http://www.gnu.org/licenses/>.
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| A special exception to the GPL is included to allow you to distribute a combined work
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| that includes OpenBLT without being obliged to provide the source code for any
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| proprietary components. The exception text is included at the bottom of the license
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| file <license.html>.
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****************************************************************************************/
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/****************************************************************************************
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* Include files
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****************************************************************************************/
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#include "header.h" /* generic header */
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/****************************************************************************************
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* Local data declarations
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****************************************************************************************/
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static unsigned long millisecond_counter;
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/****************************************************************************************
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* External functions
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****************************************************************************************/
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extern void TIMER0_ISR(void);
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/****************************************************************************************
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** NAME: TimerInit
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** PARAMETER: none
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** RETURN VALUE: none
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** DESCRIPTION: Initializes the timer.
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**
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****************************************************************************************/
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void TimerInit(void)
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{
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/* configure timer0 as 1 ms software output compare */
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T0MR0 = BOOT_CPU_SYSTEM_SPEED_KHZ-1;
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/* enable interrupt and automatic reset upon compare */
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T0MCR = 0x01 | 0x02;
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/* enable the output compare */
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T0TCR = 0x01;
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/* set the interrupt service routine for the output compare event */
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VICVectAddr0 = (unsigned long)TIMER0_ISR;
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/* connect vectored IRQ slot 0 to Timer0's channel 4 */
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VICVectCntl0 = 0x20 | 4;
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/* enable the timer0 interrupt */
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VICIntEnable = 0x10;
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/* reset the millisecond counter */
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TimerSet(0);
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} /*** end of TimerInit ***/
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/****************************************************************************************
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** NAME: TimerUpdate
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** PARAMETER: none
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** RETURN VALUE: none
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** DESCRIPTION: Updates the millisecond timer. Should be called every millisecond by
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** the timer interrupt service routine.
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**
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****************************************************************************************/
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void TimerUpdate(void)
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{
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/* increment the millisecond counter */
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millisecond_counter++;
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} /*** end of TimerUpdate ***/
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/****************************************************************************************
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** NAME: TimerSet
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** PARAMETER: timer_value initialize value of the millisecond timer.
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** RETURN VALUE: none
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** DESCRIPTION: Sets the initial counter value of the millisecond timer.
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**
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****************************************************************************************/
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void TimerSet(unsigned long timer_value)
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{
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/* set the millisecond counter */
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millisecond_counter = timer_value;
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} /*** end of TimerSet ***/
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/****************************************************************************************
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** NAME: TimerGet
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** PARAMETER: none
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** RETURN VALUE: current value of the millisecond timer
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** DESCRIPTION: Obtains the counter value of the millisecond timer.
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**
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****************************************************************************************/
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unsigned long TimerGet(void)
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{
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/* read and return the millisecond counter value */
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return millisecond_counter;
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} /*** end of TimerGet ***/
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/*********************************** end of timer.c ************************************/
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