amiro-blt / Target / Source / ARMCM4_STM32 / timer.c @ 9ed9243f
History | View | Annotate | Download (4.944 KB)
| 1 |
/************************************************************************************//** |
|---|---|
| 2 |
* \file Source\ARMCM4_STM32\timer.c
|
| 3 |
* \brief Bootloader timer driver source file.
|
| 4 |
* \ingroup Target_ARMCM4_STM32
|
| 5 |
* \internal
|
| 6 |
*----------------------------------------------------------------------------------------
|
| 7 |
* C O P Y R I G H T
|
| 8 |
*----------------------------------------------------------------------------------------
|
| 9 |
* Copyright (c) 2013 by Feaser http://www.feaser.com All rights reserved
|
| 10 |
*
|
| 11 |
*----------------------------------------------------------------------------------------
|
| 12 |
* L I C E N S E
|
| 13 |
*----------------------------------------------------------------------------------------
|
| 14 |
* This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
|
| 15 |
* modify it under the terms of the GNU General Public License as published by the Free
|
| 16 |
* Software Foundation, either version 3 of the License, or (at your option) any later
|
| 17 |
* version.
|
| 18 |
*
|
| 19 |
* OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
|
| 20 |
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
|
| 21 |
* PURPOSE. See the GNU General Public License for more details.
|
| 22 |
*
|
| 23 |
* You should have received a copy of the GNU General Public License along with OpenBLT.
|
| 24 |
* If not, see <http://www.gnu.org/licenses/>.
|
| 25 |
*
|
| 26 |
* A special exception to the GPL is included to allow you to distribute a combined work
|
| 27 |
* that includes OpenBLT without being obliged to provide the source code for any
|
| 28 |
* proprietary components. The exception text is included at the bottom of the license
|
| 29 |
* file <license.html>.
|
| 30 |
*
|
| 31 |
* \endinternal
|
| 32 |
****************************************************************************************/
|
| 33 |
|
| 34 |
/****************************************************************************************
|
| 35 |
* Include files
|
| 36 |
****************************************************************************************/
|
| 37 |
#include "boot.h" /* bootloader generic header */ |
| 38 |
#include "stm32f4xx.h" /* STM32 registers */ |
| 39 |
|
| 40 |
|
| 41 |
/****************************************************************************************
|
| 42 |
* Local data declarations
|
| 43 |
****************************************************************************************/
|
| 44 |
/** \brief Local variable for storing the number of milliseconds that have elapsed since
|
| 45 |
* startup.
|
| 46 |
*/
|
| 47 |
static blt_int32u millisecond_counter;
|
| 48 |
|
| 49 |
|
| 50 |
/************************************************************************************//** |
| 51 |
** \brief Initializes the polling based millisecond timer driver.
|
| 52 |
** \return none.
|
| 53 |
**
|
| 54 |
****************************************************************************************/
|
| 55 |
void TimerInit(void) |
| 56 |
{
|
| 57 |
/* reset the timer configuration */
|
| 58 |
TimerReset(); |
| 59 |
|
| 60 |
/* configure the systick frequency as a 1 ms event generator */
|
| 61 |
SysTick->LOAD = BOOT_CPU_SYSTEM_SPEED_KHZ - 1;
|
| 62 |
/* reset the current counter value */
|
| 63 |
SysTick->VAL = 0;
|
| 64 |
/* select core clock as source and enable the timer */
|
| 65 |
SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_ENABLE_Msk; |
| 66 |
/* reset the millisecond counter value */
|
| 67 |
millisecond_counter = 0;
|
| 68 |
} /*** end of TimerInit ***/
|
| 69 |
|
| 70 |
|
| 71 |
/************************************************************************************//** |
| 72 |
** \brief Reset the timer by placing the timer back into it's default reset
|
| 73 |
** configuration.
|
| 74 |
** \return none.
|
| 75 |
**
|
| 76 |
****************************************************************************************/
|
| 77 |
void TimerReset(void) |
| 78 |
{
|
| 79 |
/* set the systick's status and control register back into the default reset value */
|
| 80 |
SysTick->CTRL = 0;
|
| 81 |
} /* end of TimerReset */
|
| 82 |
|
| 83 |
|
| 84 |
/************************************************************************************//** |
| 85 |
** \brief Updates the millisecond timer.
|
| 86 |
** \return none.
|
| 87 |
**
|
| 88 |
****************************************************************************************/
|
| 89 |
void TimerUpdate(void) |
| 90 |
{
|
| 91 |
/* check if the millisecond event occurred */
|
| 92 |
if ((SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk) != 0) |
| 93 |
{
|
| 94 |
/* increment the millisecond counter */
|
| 95 |
millisecond_counter++; |
| 96 |
} |
| 97 |
} /*** end of TimerUpdate ***/
|
| 98 |
|
| 99 |
|
| 100 |
/************************************************************************************//** |
| 101 |
** \brief Obtains the counter value of the millisecond timer.
|
| 102 |
** \return Current value of the millisecond timer.
|
| 103 |
**
|
| 104 |
****************************************************************************************/
|
| 105 |
blt_int32u TimerGet(void)
|
| 106 |
{
|
| 107 |
/* updating timer here allows this function to be called in a loop with timeout
|
| 108 |
* detection.
|
| 109 |
*/
|
| 110 |
TimerUpdate(); |
| 111 |
/* read and return the amount of milliseconds that passed since initialization */
|
| 112 |
return millisecond_counter;
|
| 113 |
} /*** end of TimerGet ***/
|
| 114 |
|
| 115 |
|
| 116 |
/*********************************** end of timer.c ************************************/
|