main.c

STM32 库文件

/**
  ******************************************************************************
  * @file CortexM3/Mode_Privilege/main.c 
  * @author  MCD Application Team
  * @version  V3.0.0
  * @date  04/06/2009
  * @brief  Main program body.
  ******************************************************************************
  * @copy
  *
  * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
  * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
  * TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
  * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
  * FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
  * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
  *
  * <h2><center>&copy; COPYRIGHT 2009 STMicroelectronics</center></h2>
  */ 

/* Includes ------------------------------------------------------------------*/
#include "stm32f10x.h"

/** @addtogroup StdPeriph_Examples
  * @{
  */

/** @addtogroup CortexM3_Mode_Privilege
  * @{
  */ 

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define SP_PROCESS_SIZE             0x200  /* Process stack size */
#define SP_PROCESS                  0x02   /* Process stack */
#define SP_MAIN                     0x00   /* Main stack */
#define THREAD_MODE_PRIVILEGED      0x00   /* Thread mode has privileged access */
#define THREAD_MODE_UNPRIVILEGED    0x01   /* Thread mode has unprivileged access */

/* Private macro -------------------------------------------------------------*/ 
#if defined ( __CC_ARM   )
__ASM void __SVC(void) 
{ 
  SVC 0x01 
  BX R14
}
#elif defined ( __ICCARM__ )
static __INLINE  void __SVC()                     { __ASM ("svc 0x01");}
#elif defined   (  __GNUC__  )
static __INLINE void __SVC()                      { __ASM volatile ("svc 0x01");}
#endif
/* Private variables ---------------------------------------------------------*/
__IO uint8_t PSPMemAlloc[SP_PROCESS_SIZE];
__IO uint32_t Index = 0, PSPValue = 0, CurrentStack = 0, ThreadMode = 0;
ErrorStatus HSEStartUpStatus;

/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program.
  * @param  None
  * @retval : None
  */
int main(void)
{   
  /* Clock configuration */
  RCC_Configuration();
    
/* Switch Thread mode Stack from Main to Process -----------------------------*/
  /* Initialize memory reserved for Process Stack */
  for(Index = 0; Index < SP_PROCESS_SIZE; Index++)
  {
    PSPMemAlloc[Index] = 0x00;
  }

  /* Set Process stack value */ 
  __set_PSP((uint32_t)PSPMemAlloc + SP_PROCESS_SIZE);
  
  /* Select Process Stack as Thread mode Stack */
  __set_CONTROL(SP_PROCESS);

  /* Get the Thread mode stack used */
  if((__get_CONTROL() & 0x02) == SP_MAIN)
  {
    /* Main stack is used as the current stack */
    CurrentStack = SP_MAIN;
  }
  else
  {
    /* Process stack is used as the current stack */
    CurrentStack = SP_PROCESS;

    /* Get process stack pointer value */
    PSPValue = __get_PSP();	
  }
  
/* Switch Thread mode from privileged to unprivileged ------------------------*/
  /* Thread mode has unprivileged access */
  __set_CONTROL(THREAD_MODE_UNPRIVILEGED | SP_PROCESS);
  /* Unprivileged access mainly affect ability to:
      - Use or not use certain instructions such as MSR fields
      - Access System Control Space (SCS) registers such as NVIC and SysTick */

  /* Check Thread mode privilege status */
  if((__get_CONTROL() & 0x01) == THREAD_MODE_PRIVILEGED)
  {
    /* Thread mode has privileged access  */
    ThreadMode = THREAD_MODE_PRIVILEGED;
  }
  else
  {
    /* Thread mode has unprivileged access*/
    ThreadMode = THREAD_MODE_UNPRIVILEGED;
  }

/* Switch back Thread mode from unprivileged to privileged -------------------*/  
  /* Try to switch back Thread mode to privileged (Not possible, this can be
     done only in Handler mode) */
  __set_CONTROL(THREAD_MODE_PRIVILEGED | SP_PROCESS);

  /* Generate a system call exception, and in the ISR switch back Thread mode
    to privileged */
  __SVC();

  /* Check Thread mode privilege status */
  if((__get_CONTROL() & 0x01) == THREAD_MODE_PRIVILEGED)
  {
    /* Thread mode has privileged access  */
    ThreadMode = THREAD_MODE_PRIVILEGED;
  }
  else
  {
    /* Thread mode has unprivileged access*/
    ThreadMode = THREAD_MODE_UNPRIVILEGED;
  }

  while (1)
  {
  }
}

/**
  * @brief  Configures the different system clocks.
  * @param  None
  * @retval : None
  */
void RCC_Configuration(void)
{
  /* RCC system reset(for debug purpose) */
  RCC_DeInit();

  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);

  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();

  if(HSEStartUpStatus == SUCCESS)
  {
    /* Enable Prefetch Buffer */
    FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

    /* Flash 0 wait state */
    FLASH_SetLatency(FLASH_Latency_0);
 
    /* HCLK = SYSCLK */
    RCC_HCLKConfig(RCC_SYSCLK_Div1); 
  
    /* PCLK2 = HCLK */
    RCC_PCLK2Config(RCC_HCLK_Div1); 

    /* PCLK1 = HCLK */
    RCC_PCLK1Config(RCC_HCLK_Div1);

    /* Select HSE as system clock source */
    RCC_SYSCLKConfig(RCC_SYSCLKSource_HSE);

    /* Wait till HSE is used as system clock source */
    while(RCC_GetSYSCLKSource() != 0x04)
    {
    }
  }
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *   where the assert_param error has occurred.
  * @param file: pointer to the source file name
  * @param line: assert_param error line source number
  * @retval : None
  */
void assert_failed(uint8_t* file, uint32_t line)
{ 
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
}
#endif

/**
  * @}
  */ 

/**
  * @}
  */ 

/******************* (C) COPYRIGHT 2009 STMicroelectronics *****END OF FILE****/