amiro-blt / Target / Source / ARMCM4_STM32 / timer.c @ 4745cc4c
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/************************************************************************************//** |
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* \file Source\ARMCM4_STM32\timer.c
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* \brief Bootloader timer driver source file.
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* \ingroup Target_ARMCM4_STM32
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* \internal
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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) 2013 by Feaser http://www.feaser.com All rights reserved
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*
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*----------------------------------------------------------------------------------------
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* L I C E N S E
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*----------------------------------------------------------------------------------------
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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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*
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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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*
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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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*
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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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* \endinternal
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****************************************************************************************/
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/****************************************************************************************
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* Include files
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****************************************************************************************/
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#include "boot.h" /* bootloader generic header */ |
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#include "stm32f4xx.h" /* STM32 registers */ |
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/****************************************************************************************
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* Local data declarations
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****************************************************************************************/
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/** \brief Local variable for storing the number of milliseconds that have elapsed since
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* startup.
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*/
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static blt_int32u millisecond_counter;
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/************************************************************************************//** |
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** \brief Initializes the polling based millisecond timer driver.
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** \return none.
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**
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****************************************************************************************/
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void TimerInit(void) |
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{
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/* reset the timer configuration */
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TimerReset(); |
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/* configure the systick frequency as a 1 ms event generator */
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SysTick->LOAD = BOOT_CPU_SYSTEM_SPEED_KHZ - 1;
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/* reset the current counter value */
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SysTick->VAL = 0;
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/* select core clock as source and enable the timer */
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SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_ENABLE_Msk; |
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/* reset the millisecond counter value */
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millisecond_counter = 0;
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} /*** end of TimerInit ***/
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/************************************************************************************//** |
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** \brief Reset the timer by placing the timer back into it's default reset
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** configuration.
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** \return none.
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**
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****************************************************************************************/
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void TimerReset(void) |
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{
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/* set the systick's status and control register back into the default reset value */
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SysTick->CTRL = 0;
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} /* end of TimerReset */
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/************************************************************************************//** |
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** \brief Updates the millisecond timer.
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** \return none.
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**
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****************************************************************************************/
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void TimerUpdate(void) |
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{
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/* check if the millisecond event occurred */
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if ((SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk) != 0) |
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{
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/* increment the millisecond counter */
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millisecond_counter++; |
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} |
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} /*** end of TimerUpdate ***/
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/************************************************************************************//** |
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** \brief Obtains the counter value of the millisecond timer.
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** \return Current value of the millisecond timer.
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**
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****************************************************************************************/
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blt_int32u TimerGet(void)
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{
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/* updating timer here allows this function to be called in a loop with timeout
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* detection.
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*/
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TimerUpdate(); |
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/* read and return the amount of milliseconds that passed since initialization */
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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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