amiro-blt / Target / Source / ARMCM4_STM32 / timer.c @ 69661903
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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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