mirror of https://github.com/FOME-Tech/openblt.git
145 lines
5.9 KiB
C
145 lines
5.9 KiB
C
/************************************************************************************//**
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* \file Source\TRICORE_TC1798\timer.c
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* \brief Bootloader timer driver source file.
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* \ingroup Target_TRICORE_TC1798
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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) 2015 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 have received a copy of the GNU General Public License along with OpenBLT. It
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* should be located in ".\Doc\license.html". If not, contact Feaser to obtain a copy.
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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 "cpu_comp.h" /* compiler specific CPU definitions */
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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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/** \brief Holds the timer tick count for 1 millisecond. */
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static blt_int16u millisecond_ticks;
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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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blt_int32u dummy;
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/* reset the timer configuration */
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TimerReset();
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/* obtain "E" access rights */
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CpuEnterInitMode();
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/* enable the GPT12 timer module */
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GPT120_CLC.reg = 0x00000000;
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/* dummy read to avoid pipeline effects */
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dummy = GPT120_CLC.reg;
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/* release "E" access rights */
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CpuLeaveInitMode();
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/* core timer 3 is used for polling millisecond events. its configuration is:
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* - timer 3 works in timer mode
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* - external up/down control is disabled
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* - prescaler factor is 128 (Ftimer3 = BOOT_CPU_SYSTEM_SPEED_KHZ / 128)
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* - up/down control bit is reset
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* - alternate output function T3OUT is disabled
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* - timer 3 output toggle latch (T3OTL) is set to 0
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* - timer 3 run bit is set
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*/
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GPT120_T3CON.reg = 0x00000845;
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/* reset the timer 3 register so that counter starts at 0 */
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GPT120_T3.reg = 0x00000000;
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/* calculate the number of timer ticks in 1 millisecond */
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millisecond_ticks = ((blt_int32u)BOOT_CPU_SYSTEM_SPEED_KHZ / 128);
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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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blt_int32u dummy;
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/* revert back to timer 3 configuration reset value */
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GPT120_T3CON.reg = 0x00000000;
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/* revert back to timer 3 reset value */
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GPT120_T3.reg = 0x00000000;
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/* obtain "E" access rights */
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CpuEnterInitMode();
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/* disable the GPT12 timer module */
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GPT120_CLC.reg = 0x00000003;
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/* dummy read to avoid pipeline effects */
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dummy = GPT120_CLC.reg;
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/* release "E" access rights */
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CpuLeaveInitMode();
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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 (GPT120_T3.reg >= millisecond_ticks)
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{
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GPT120_T3.reg = 0;
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/* reset timer 3 register for detecting the next millisecond */
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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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