amiro-blt / Target / Source / ARMCM4_STM32 / timer.c @ c9c97bb3
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| 1 | 69661903 | Thomas Schöpping | /************************************************************************************//** |
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| 2 | * \file Source\ARMCM4_STM32\timer.c
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| 3 | * \brief Bootloader timer driver source file.
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| 4 | * \ingroup Target_ARMCM4_STM32
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| 5 | * \internal
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| 6 | *----------------------------------------------------------------------------------------
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| 7 | * C O P Y R I G H T
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| 8 | *----------------------------------------------------------------------------------------
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| 9 | * Copyright (c) 2013 by Feaser http://www.feaser.com All rights reserved
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| 10 | *
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| 11 | *----------------------------------------------------------------------------------------
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| 12 | * L I C E N S E
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| 13 | *----------------------------------------------------------------------------------------
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| 14 | * This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
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| 15 | * modify it under the terms of the GNU General Public License as published by the Free
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| 16 | * Software Foundation, either version 3 of the License, or (at your option) any later
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| 17 | * version.
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| 18 | *
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| 19 | * OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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| 20 | * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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| 21 | * PURPOSE. See the GNU General Public License for more details.
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| 22 | *
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| 23 | * You should have received a copy of the GNU General Public License along with OpenBLT.
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| 24 | * If not, see <http://www.gnu.org/licenses/>.
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| 25 | *
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| 26 | * A special exception to the GPL is included to allow you to distribute a combined work
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| 27 | * that includes OpenBLT without being obliged to provide the source code for any
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| 28 | * proprietary components. The exception text is included at the bottom of the license
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| 29 | * file <license.html>.
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| 30 | *
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| 31 | * \endinternal
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| 32 | ****************************************************************************************/
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| 33 | |||
| 34 | /****************************************************************************************
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| 35 | * Include files
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| 36 | ****************************************************************************************/
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| 37 | #include "boot.h" /* bootloader generic header */ |
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| 38 | #include "stm32f4xx.h" /* STM32 registers */ |
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| 39 | |||
| 40 | |||
| 41 | /****************************************************************************************
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| 42 | * Local data declarations
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| 43 | ****************************************************************************************/
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| 44 | /** \brief Local variable for storing the number of milliseconds that have elapsed since
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| 45 | * startup.
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| 46 | */
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| 47 | static blt_int32u millisecond_counter;
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| 48 | |||
| 49 | |||
| 50 | /************************************************************************************//** |
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| 51 | ** \brief Initializes the polling based millisecond timer driver.
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| 52 | ** \return none.
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| 53 | **
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| 54 | ****************************************************************************************/
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| 55 | void TimerInit(void) |
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| 56 | {
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| 57 | /* reset the timer configuration */
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| 58 | TimerReset(); |
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| 59 | |||
| 60 | /* configure the systick frequency as a 1 ms event generator */
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| 61 | SysTick->LOAD = BOOT_CPU_SYSTEM_SPEED_KHZ - 1;
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| 62 | /* reset the current counter value */
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| 63 | SysTick->VAL = 0;
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| 64 | /* select core clock as source and enable the timer */
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| 65 | SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_ENABLE_Msk; |
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| 66 | /* reset the millisecond counter value */
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| 67 | millisecond_counter = 0;
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| 68 | } /*** end of TimerInit ***/
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| 69 | |||
| 70 | |||
| 71 | /************************************************************************************//** |
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| 72 | ** \brief Reset the timer by placing the timer back into it's default reset
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| 73 | ** configuration.
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| 74 | ** \return none.
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| 75 | **
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| 76 | ****************************************************************************************/
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| 77 | void TimerReset(void) |
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| 78 | {
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| 79 | /* set the systick's status and control register back into the default reset value */
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| 80 | SysTick->CTRL = 0;
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| 81 | } /* end of TimerReset */
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| 82 | |||
| 83 | |||
| 84 | /************************************************************************************//** |
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| 85 | ** \brief Updates the millisecond timer.
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| 86 | ** \return none.
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| 87 | **
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| 88 | ****************************************************************************************/
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| 89 | void TimerUpdate(void) |
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| 90 | {
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| 91 | /* check if the millisecond event occurred */
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| 92 | if ((SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk) != 0) |
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| 93 | {
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| 94 | /* increment the millisecond counter */
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| 95 | millisecond_counter++; |
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| 96 | } |
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| 97 | } /*** end of TimerUpdate ***/
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| 98 | |||
| 99 | |||
| 100 | /************************************************************************************//** |
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| 101 | ** \brief Obtains the counter value of the millisecond timer.
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| 102 | ** \return Current value of the millisecond timer.
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| 103 | **
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| 104 | ****************************************************************************************/
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| 105 | blt_int32u TimerGet(void)
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| 106 | {
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| 107 | /* updating timer here allows this function to be called in a loop with timeout
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| 108 | * detection.
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| 109 | */
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| 110 | TimerUpdate(); |
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| 111 | /* read and return the amount of milliseconds that passed since initialization */
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| 112 | return millisecond_counter;
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| 113 | } /*** end of TimerGet ***/
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| 114 | |||
| 115 | |||
| 116 | /*********************************** end of timer.c ************************************/
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