137 lines
5.3 KiB
C
137 lines
5.3 KiB
C
/************************************************************************************//**
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* \file Demo\HCS12_Evbplus_Dragon12p_CodeWarrior\Boot\main.c
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* \brief Bootloader application source file.
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* \ingroup Boot_HCS12_Evbplus_Dragon12p_CodeWarrior
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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 "derivative.h" /* MCU registers */
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/****************************************************************************************
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* Function prototypes
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****************************************************************************************/
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static void Init(void);
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/************************************************************************************//**
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** \brief This is the entry point for the bootloader application and is called
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** by the reset interrupt vector after the C-startup routines executed.
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** \return none.
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**
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****************************************************************************************/
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void main(void)
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{
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/* ##Vg TODO basic bootloader works, including the timed backdoor. next steps:
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* - bootloader activation from user program
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* - support for CAN
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*/
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/* initialize the microcontroller */
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Init();
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/* initialize the bootloader */
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BootInit();
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/* start the infinite program loop */
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while (1)
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{
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/* run the bootloader task */
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BootTask();
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}
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} /*** end of main ***/
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/************************************************************************************//**
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** \brief Initializes the microcontroller.
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** \return none.
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**
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****************************************************************************************/
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static void Init(void)
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{
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blt_int8u synrCnt;
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blt_int8u refdvCnt;
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blt_int32u systemSpeed;
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blt_bool found = BLT_FALSE;
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/* disable the global interrupts. the bootloader does not use interrupts and this
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* automatically prevents a jump back into the user program in case it was not
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* properly uninitialized.
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*/
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asm("sei");
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/* initialize the system clock to BOOT_CPU_SYSTEM_SPEED_KHZ by configuring the PLL
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* subsystem. first default to oscillator clock source.
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*/
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CLKSEL &= ~0x80;
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/* search for the synthesizer and reference divider values. the equation to use is:
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* PLLCLK = EXTCLK * ( (synrCnt + 1) / (refdvCnt + 1) ), with synrCnt can be from
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* 0..63 and refdvCnt can be from 0..15
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*/
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for (refdvCnt = 0; refdvCnt <= 15; refdvCnt++)
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{
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for (synrCnt = 0; synrCnt <= 63; synrCnt++)
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{
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/* calculate the system speed with these SYNR and REFDV settings */
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systemSpeed = ((blt_int32u)BOOT_CPU_XTAL_SPEED_KHZ * (synrCnt+1)) / (refdvCnt+1);
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/* was a match found? */
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if (systemSpeed == BOOT_CPU_SYSTEM_SPEED_KHZ)
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{
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/* flag success */
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found = BLT_TRUE;
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/* break loop */
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break;
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}
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}
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if (found == BLT_TRUE)
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{
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/* break this loop as well if a match was already found */
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break;
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}
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}
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/* flag error if no match was found */
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ASSERT_RT(found == BLT_TRUE);
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/* set the synthesizer and reference divider values */
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SYNR = synrCnt;
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REFDV = refdvCnt;
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/* wait for PLL to lock */
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while((CRGFLG & 0x08) == 0)
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{
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;
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}
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/* select PLL as clock source */
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CLKSEL |= 0x80;
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} /*** end of Init ***/
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/*********************************** end of main.c *************************************/
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