162 lines
6.5 KiB
C
162 lines
6.5 KiB
C
/****************************************************************************************
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| Description: demo program application source file
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| File Name: main.c
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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) 2011 by Feaser http://www.feaser.com All rights reserved
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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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| 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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| 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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| 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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/****************************************************************************************
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* Include files
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****************************************************************************************/
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#include "header.h" /* generic header */
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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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** NAME: main
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** PARAMETER: none
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** RETURN VALUE: program return code
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** DESCRIPTION: 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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**
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****************************************************************************************/
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int main(void)
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{
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/* initialize the microcontroller */
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Init();
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/* initialize the bootloader interface */
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BootComInit();
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/* start the infinite program loop */
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while (1)
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{
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/* toggle LED with a fixed frequency */
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LedToggle();
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/* check for bootloader activation request */
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BootComCheckActivationRequest();
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}
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/* program should never get here */
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return 0;
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} /*** end of main ***/
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/****************************************************************************************
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** NAME: Init
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** PARAMETER: none
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** RETURN VALUE: none
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** DESCRIPTION: Initializes the microcontroller.
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**
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****************************************************************************************/
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static void Init(void)
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{
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volatile unsigned long StartUpCounter = 0, HSEStatus = 0;
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unsigned long pll_multiplier;
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/* reset the RCC clock configuration to the default reset state (for debug purpose) */
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/* set HSION bit */
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RCC->CR |= (unsigned long)0x00000001;
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/* reset SW, HPRE, PPRE1, PPRE2, ADCPRE and MCO bits */
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RCC->CFGR &= (unsigned long)0xF8FF0000;
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/* reset HSEON, CSSON and PLLON bits */
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RCC->CR &= (unsigned long)0xFEF6FFFF;
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/* reset HSEBYP bit */
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RCC->CR &= (unsigned long)0xFFFBFFFF;
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/* reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE/OTGFSPRE bits */
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RCC->CFGR &= (unsigned long)0xFF80FFFF;
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/* disable all interrupts and clear pending bits */
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RCC->CIR = 0x009F0000;
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/* enable HSE */
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RCC->CR |= ((unsigned long)RCC_CR_HSEON);
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/* wait till HSE is ready and if Time out is reached exit */
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do
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{
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HSEStatus = RCC->CR & RCC_CR_HSERDY;
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StartUpCounter++;
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}
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while((HSEStatus == 0) && (StartUpCounter != 1500));
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/* check if time out was reached */
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if ((RCC->CR & RCC_CR_HSERDY) == RESET)
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{
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/* cannot continue when HSE is not ready */
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while (1) { ; }
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}
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/* enable flash prefetch buffer */
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FLASH->ACR |= FLASH_ACR_PRFTBE;
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/* reset flash wait state configuration to default 0 wait states */
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FLASH->ACR &= (unsigned long)((unsigned long)~FLASH_ACR_LATENCY);
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#if (BOOT_CPU_SYSTEM_SPEED_KHZ > 48000)
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/* configure 2 flash wait states */
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FLASH->ACR |= (unsigned long)FLASH_ACR_LATENCY_2;
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#elif (BOOT_CPU_SYSTEM_SPEED_KHZ > 24000)
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/* configure 1 flash wait states */
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FLASH->ACR |= (unsigned long)FLASH_ACR_LATENCY_1;
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#endif
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/* HCLK = SYSCLK */
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RCC->CFGR |= (unsigned long)RCC_CFGR_HPRE_DIV1;
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/* PCLK2 = HCLK/2 */
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RCC->CFGR |= (unsigned long)RCC_CFGR_PPRE2_DIV2;
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/* PCLK1 = HCLK/2 */
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RCC->CFGR |= (unsigned long)RCC_CFGR_PPRE1_DIV2;
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/* reset PLL configuration */
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RCC->CFGR &= (unsigned long)((unsigned long)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | \
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RCC_CFGR_PLLMULL));
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/* calculate multiplier value */
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pll_multiplier = BOOT_CPU_SYSTEM_SPEED_KHZ/BOOT_CPU_XTAL_SPEED_KHZ;
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/* convert to register value */
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pll_multiplier = (unsigned long)((pll_multiplier - 2) << 18);
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/* set the PLL multiplier and clock source */
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RCC->CFGR |= (unsigned long)(RCC_CFGR_PLLSRC_HSE | pll_multiplier);
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/* enable PLL */
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RCC->CR |= RCC_CR_PLLON;
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/* wait till PLL is ready */
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while((RCC->CR & RCC_CR_PLLRDY) == 0)
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{
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}
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/* select PLL as system clock source */
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RCC->CFGR &= (unsigned long)((unsigned long)~(RCC_CFGR_SW));
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RCC->CFGR |= (unsigned long)RCC_CFGR_SW_PLL;
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/* wait till PLL is used as system clock source */
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while ((RCC->CFGR & (unsigned long)RCC_CFGR_SWS) != (unsigned long)0x08)
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{
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}
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/* init the led driver */
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LedInit();
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/* init the timer driver */
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TimerInit();
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/* enable IRQ's, because they were initially disabled by the bootloader */
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IrqInterruptEnable();
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} /*** end of Init ***/
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/*********************************** end of main.c *************************************/
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