www.pudn.com > STM32--LED.rar > stm32f10x_flash.c, change:2009-04-06,size:26352b


/** 
  ****************************************************************************** 
  * @file  stm32f10x_flash.c 
  * @author  MCD Application Team 
  * @version  V3.0.0 
  * @date  04/06/2009 
  * @brief  This file provides all the FLASH firmware functions. 
  ****************************************************************************** 
  * @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>© COPYRIGHT 2009 STMicroelectronics</center></h2> 
  */  
 
/* Includes ------------------------------------------------------------------*/ 
#include "stm32f10x_flash.h" 
 
/** @addtogroup StdPeriph_Driver 
  * @{ 
  */ 
 
/** @defgroup FLASH  
  * @brief FLASH driver modules 
  * @{ 
  */  
 
/** @defgroup FLASH_Private_TypesDefinitions 
  * @{ 
  */ 
 
/** 
  * @} 
  */  
 
/** @defgroup FLASH_Private_Defines 
  * @{ 
  */  
 
/* Flash Access Control Register bits */ 
#define ACR_LATENCY_Mask         ((uint32_t)0x00000038) 
#define ACR_HLFCYA_Mask          ((uint32_t)0xFFFFFFF7) 
#define ACR_PRFTBE_Mask          ((uint32_t)0xFFFFFFEF) 
 
/* Flash Access Control Register bits */ 
#define ACR_PRFTBS_Mask          ((uint32_t)0x00000020)  
 
/* Flash Control Register bits */ 
#define CR_PG_Set                ((uint32_t)0x00000001) 
#define CR_PG_Reset              ((uint32_t)0x00001FFE)  
#define CR_PER_Set               ((uint32_t)0x00000002) 
#define CR_PER_Reset             ((uint32_t)0x00001FFD) 
#define CR_MER_Set               ((uint32_t)0x00000004) 
#define CR_MER_Reset             ((uint32_t)0x00001FFB) 
#define CR_OPTPG_Set             ((uint32_t)0x00000010) 
#define CR_OPTPG_Reset           ((uint32_t)0x00001FEF) 
#define CR_OPTER_Set             ((uint32_t)0x00000020) 
#define CR_OPTER_Reset           ((uint32_t)0x00001FDF) 
#define CR_STRT_Set              ((uint32_t)0x00000040) 
#define CR_LOCK_Set              ((uint32_t)0x00000080) 
 
/* FLASH Mask */ 
#define RDPRT_Mask               ((uint32_t)0x00000002) 
#define WRP0_Mask                ((uint32_t)0x000000FF) 
#define WRP1_Mask                ((uint32_t)0x0000FF00) 
#define WRP2_Mask                ((uint32_t)0x00FF0000) 
#define WRP3_Mask                ((uint32_t)0xFF000000) 
 
/* FLASH Keys */ 
#define RDP_Key                  ((uint16_t)0x00A5) 
#define FLASH_KEY1               ((uint32_t)0x45670123) 
#define FLASH_KEY2               ((uint32_t)0xCDEF89AB) 
 
/* Delay definition */    
#define EraseTimeout             ((uint32_t)0x00000FFF) 
#define ProgramTimeout           ((uint32_t)0x0000000F) 
 
/** 
  * @} 
  */  
 
/** @defgroup FLASH_Private_Macros 
  * @{ 
  */ 
 
/** 
  * @} 
  */  
 
/** @defgroup FLASH_Private_Variables 
  * @{ 
  */ 
 
/** 
  * @} 
  */  
 
/** @defgroup FLASH_Private_FunctionPrototypes 
  * @{ 
  */ 
 
static void delay(void); 
/** 
  * @} 
  */ 
 
/** @defgroup FLASH_Private_Functions 
  * @{ 
  */ 
 
/** 
  * @brief  Sets the code latency value. 
  * @param FLASH_Latency: specifies the FLASH Latency value. 
  *   This parameter can be one of the following values: 
  * @arg FLASH_Latency_0: FLASH Zero Latency cycle 
  * @arg FLASH_Latency_1: FLASH One Latency cycle 
  * @arg FLASH_Latency_2: FLASH Two Latency cycles 
  * @retval : None 
  */ 
void FLASH_SetLatency(uint32_t FLASH_Latency) 
{ 
  uint32_t tmpreg = 0; 
   
  /* Check the parameters */ 
  assert_param(IS_FLASH_LATENCY(FLASH_Latency)); 
   
  /* Read the ACR register */ 
  tmpreg = FLASH->ACR;   
   
  /* Sets the Latency value */ 
  tmpreg &= ACR_LATENCY_Mask; 
  tmpreg |= FLASH_Latency; 
   
  /* Write the ACR register */ 
  FLASH->ACR = tmpreg; 
} 
 
/** 
  * @brief  Enables or disables the Half cycle flash access. 
  * @param FLASH_HalfCycleAccess: specifies the FLASH Half cycle Access mode. 
  *   This parameter can be one of the following values: 
  * @arg FLASH_HalfCycleAccess_Enable: FLASH Half Cycle Enable 
  * @arg FLASH_HalfCycleAccess_Disable: FLASH Half Cycle Disable 
  * @retval : None 
  */ 
void FLASH_HalfCycleAccessCmd(uint32_t FLASH_HalfCycleAccess) 
{ 
  /* Check the parameters */ 
  assert_param(IS_FLASH_HALFCYCLEACCESS_STATE(FLASH_HalfCycleAccess)); 
   
  /* Enable or disable the Half cycle access */ 
  FLASH->ACR &= ACR_HLFCYA_Mask; 
  FLASH->ACR |= FLASH_HalfCycleAccess; 
} 
 
/** 
  * @brief  Enables or disables the Prefetch Buffer. 
  * @param FLASH_PrefetchBuffer: specifies the Prefetch buffer status. 
  *   This parameter can be one of the following values: 
  * @arg FLASH_PrefetchBuffer_Enable: FLASH Prefetch Buffer Enable 
  * @arg FLASH_PrefetchBuffer_Disable: FLASH Prefetch Buffer Disable 
  * @retval : None 
  */ 
void FLASH_PrefetchBufferCmd(uint32_t FLASH_PrefetchBuffer) 
{ 
  /* Check the parameters */ 
  assert_param(IS_FLASH_PREFETCHBUFFER_STATE(FLASH_PrefetchBuffer)); 
   
  /* Enable or disable the Prefetch Buffer */ 
  FLASH->ACR &= ACR_PRFTBE_Mask; 
  FLASH->ACR |= FLASH_PrefetchBuffer; 
} 
 
/** 
  * @brief  Unlocks the FLASH Program Erase Controller. 
  * @param  None 
  * @retval : None 
  */ 
void FLASH_Unlock(void) 
{ 
  /* Authorize the FPEC Access */ 
  FLASH->KEYR = FLASH_KEY1; 
  FLASH->KEYR = FLASH_KEY2; 
} 
 
/** 
  * @brief  Locks the FLASH Program Erase Controller. 
  * @param  None 
  * @retval : None 
  */ 
void FLASH_Lock(void) 
{ 
  /* Set the Lock Bit to lock the FPEC and the FCR */ 
  FLASH->CR |= CR_LOCK_Set; 
} 
 
/** 
  * @brief  Erases a specified FLASH page. 
  * @param Page_Address: The page address to be erased. 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT. 
  */ 
FLASH_Status FLASH_ErasePage(uint32_t Page_Address) 
{ 
  FLASH_Status status = FLASH_COMPLETE; 
  /* Check the parameters */ 
  assert_param(IS_FLASH_ADDRESS(Page_Address)); 
  /* Wait for last operation to be completed */ 
  status = FLASH_WaitForLastOperation(EraseTimeout); 
   
  if(status == FLASH_COMPLETE) 
  {  
    /* if the previous operation is completed, proceed to erase the page */ 
    FLASH->CR|= CR_PER_Set; 
    FLASH->AR = Page_Address;  
    FLASH->CR|= CR_STRT_Set; 
     
    /* Wait for last operation to be completed */ 
    status = FLASH_WaitForLastOperation(EraseTimeout); 
    if(status != FLASH_BUSY) 
    { 
      /* if the erase operation is completed, disable the PER Bit */ 
      FLASH->CR &= CR_PER_Reset; 
    } 
  } 
  /* Return the Erase Status */ 
  return status; 
} 
 
/** 
  * @brief  Erases all FLASH pages. 
  * @param  None 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT. 
  */ 
FLASH_Status FLASH_EraseAllPages(void) 
{ 
  FLASH_Status status = FLASH_COMPLETE; 
  /* Wait for last operation to be completed */ 
  status = FLASH_WaitForLastOperation(EraseTimeout); 
   
  if(status == FLASH_COMPLETE) 
  { 
    /* if the previous operation is completed, proceed to erase all pages */ 
     FLASH->CR |= CR_MER_Set; 
     FLASH->CR |= CR_STRT_Set; 
     
    /* Wait for last operation to be completed */ 
    status = FLASH_WaitForLastOperation(EraseTimeout); 
    if(status != FLASH_BUSY) 
    { 
      /* if the erase operation is completed, disable the MER Bit */ 
      FLASH->CR &= CR_MER_Reset; 
    } 
  }	    
  /* Return the Erase Status */ 
  return status; 
} 
 
/** 
  * @brief  Erases the FLASH option bytes. 
  * @param  None 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT. 
  */ 
FLASH_Status FLASH_EraseOptionBytes(void) 
{ 
  FLASH_Status status = FLASH_COMPLETE; 
   
  /* Wait for last operation to be completed */ 
  status = FLASH_WaitForLastOperation(EraseTimeout); 
  if(status == FLASH_COMPLETE) 
  { 
    /* Authorize the small information block programming */ 
    FLASH->OPTKEYR = FLASH_KEY1; 
    FLASH->OPTKEYR = FLASH_KEY2; 
     
    /* if the previous operation is completed, proceed to erase the option bytes */ 
    FLASH->CR |= CR_OPTER_Set; 
    FLASH->CR |= CR_STRT_Set; 
    /* Wait for last operation to be completed */ 
    status = FLASH_WaitForLastOperation(EraseTimeout); 
     
    if(status == FLASH_COMPLETE) 
    { 
      /* if the erase operation is completed, disable the OPTER Bit */ 
      FLASH->CR &= CR_OPTER_Reset; 
        
      /* Enable the Option Bytes Programming operation */ 
      FLASH->CR |= CR_OPTPG_Set; 
      /* Enable the readout access */ 
      OB->RDP= RDP_Key;  
      /* Wait for last operation to be completed */ 
      status = FLASH_WaitForLastOperation(ProgramTimeout); 
  
      if(status != FLASH_BUSY) 
      { 
        /* if the program operation is completed, disable the OPTPG Bit */ 
        FLASH->CR &= CR_OPTPG_Reset; 
      } 
    } 
    else 
    { 
      if (status != FLASH_BUSY) 
      { 
        /* Disable the OPTPG Bit */ 
        FLASH->CR &= CR_OPTPG_Reset; 
      } 
    }   
  } 
  /* Return the erase status */ 
  return status; 
} 
 
/** 
  * @brief  Programs a word at a specified address. 
  * @param Address: specifies the address to be programmed. 
  * @param Data: specifies the data to be programmed. 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT.  
  */ 
FLASH_Status FLASH_ProgramWord(uint32_t Address, uint32_t Data) 
{ 
  FLASH_Status status = FLASH_COMPLETE; 
  /* Check the parameters */ 
  assert_param(IS_FLASH_ADDRESS(Address)); 
  /* Wait for last operation to be completed */ 
  status = FLASH_WaitForLastOperation(ProgramTimeout); 
   
  if(status == FLASH_COMPLETE) 
  { 
    /* if the previous operation is completed, proceed to program the new first  
    half word */ 
    FLASH->CR |= CR_PG_Set; 
   
    *(__IO uint16_t*)Address = (uint16_t)Data; 
    /* Wait for last operation to be completed */ 
    status = FLASH_WaitForLastOperation(ProgramTimeout); 
  
    if(status == FLASH_COMPLETE) 
    { 
      /* if the previous operation is completed, proceed to program the new second  
      half word */ 
      *(__IO uint16_t*)(Address + 2) = Data >> 16; 
     
      /* Wait for last operation to be completed */ 
      status = FLASH_WaitForLastOperation(ProgramTimeout); 
         
      if(status != FLASH_BUSY) 
      { 
        /* Disable the PG Bit */ 
        FLASH->CR &= CR_PG_Reset; 
      } 
    } 
    else 
    { 
      if (status != FLASH_BUSY) 
      { 
        /* Disable the PG Bit */ 
        FLASH->CR &= CR_PG_Reset; 
      } 
     } 
  } 
  /* Return the Program Status */ 
  return status; 
} 
 
/** 
  * @brief  Programs a half word at a specified address. 
  * @param Address: specifies the address to be programmed. 
  * @param Data: specifies the data to be programmed. 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT.  
  */ 
FLASH_Status FLASH_ProgramHalfWord(uint32_t Address, uint16_t Data) 
{ 
  FLASH_Status status = FLASH_COMPLETE; 
  /* Check the parameters */ 
  assert_param(IS_FLASH_ADDRESS(Address)); 
  /* Wait for last operation to be completed */ 
  status = FLASH_WaitForLastOperation(ProgramTimeout); 
   
  if(status == FLASH_COMPLETE) 
  { 
    /* if the previous operation is completed, proceed to program the new data */ 
    FLASH->CR |= CR_PG_Set; 
   
    *(__IO uint16_t*)Address = Data; 
    /* Wait for last operation to be completed */ 
    status = FLASH_WaitForLastOperation(ProgramTimeout); 
    if(status != FLASH_BUSY) 
    { 
      /* if the program operation is completed, disable the PG Bit */ 
      FLASH->CR &= CR_PG_Reset; 
    } 
  }  
  /* Return the Program Status */ 
  return status; 
} 
 
/** 
  * @brief  Programs a half word at a specified Option Byte Data address. 
  * @param Address: specifies the address to be programmed. 
  *   This parameter can be 0x1FFFF804 or 0x1FFFF806.  
  * @param Data: specifies the data to be programmed. 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT.  
  */ 
FLASH_Status FLASH_ProgramOptionByteData(uint32_t Address, uint8_t Data) 
{ 
  FLASH_Status status = FLASH_COMPLETE; 
  /* Check the parameters */ 
  assert_param(IS_OB_DATA_ADDRESS(Address)); 
  status = FLASH_WaitForLastOperation(ProgramTimeout); 
  if(status == FLASH_COMPLETE) 
  { 
    /* Authorize the small information block programming */ 
    FLASH->OPTKEYR = FLASH_KEY1; 
    FLASH->OPTKEYR = FLASH_KEY2; 
    /* Enables the Option Bytes Programming operation */ 
    FLASH->CR |= CR_OPTPG_Set;  
    *(__IO uint16_t*)Address = Data; 
     
    /* Wait for last operation to be completed */ 
    status = FLASH_WaitForLastOperation(ProgramTimeout); 
    if(status != FLASH_BUSY) 
    { 
      /* if the program operation is completed, disable the OPTPG Bit */ 
      FLASH->CR &= CR_OPTPG_Reset; 
    } 
  }     
  /* Return the Option Byte Data Program Status */ 
  return status; 
} 
 
/** 
  * @brief  Write protects the desired pages 
  * @param FLASH_Pages: specifies the address of the pages to be  
  *   write protected. This parameter can be: 
  * @arg For STM32F10Xxx Medium-density devices (FLASH page size equal to 1 KB) 
  * A value between FLASH_WRProt_Pages0to3 and FLASH_WRProt_Pages124to127 
  * @arg For STM32F10Xxx High-density devices (FLASH page size equal to 2 KB)  
  * A value between FLASH_WRProt_Pages0to1 and  FLASH_WRProt_Pages60to61  
  * or FLASH_WRProt_Pages62to255  
  * @arg FLASH_WRProt_AllPages 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT. 
  */ 
FLASH_Status FLASH_EnableWriteProtection(uint32_t FLASH_Pages) 
{ 
  uint16_t WRP0_Data = 0xFFFF, WRP1_Data = 0xFFFF, WRP2_Data = 0xFFFF, WRP3_Data = 0xFFFF; 
   
  FLASH_Status status = FLASH_COMPLETE; 
   
  /* Check the parameters */ 
  assert_param(IS_FLASH_WRPROT_PAGE(FLASH_Pages)); 
   
  FLASH_Pages = (uint32_t)(~FLASH_Pages); 
  WRP0_Data = (uint16_t)(FLASH_Pages & WRP0_Mask); 
  WRP1_Data = (uint16_t)((FLASH_Pages & WRP1_Mask) >> 8); 
  WRP2_Data = (uint16_t)((FLASH_Pages & WRP2_Mask) >> 16); 
  WRP3_Data = (uint16_t)((FLASH_Pages & WRP3_Mask) >> 24); 
   
  /* Wait for last operation to be completed */ 
  status = FLASH_WaitForLastOperation(ProgramTimeout); 
   
  if(status == FLASH_COMPLETE) 
  { 
    /* Authorizes the small information block programming */ 
    FLASH->OPTKEYR = FLASH_KEY1; 
    FLASH->OPTKEYR = FLASH_KEY2; 
    FLASH->CR |= CR_OPTPG_Set; 
    if(WRP0_Data != 0xFF) 
    { 
      OB->WRP0 = WRP0_Data; 
       
      /* Wait for last operation to be completed */ 
      status = FLASH_WaitForLastOperation(ProgramTimeout); 
    } 
    if((status == FLASH_COMPLETE) && (WRP1_Data != 0xFF)) 
    { 
      OB->WRP1 = WRP1_Data; 
       
      /* Wait for last operation to be completed */ 
      status = FLASH_WaitForLastOperation(ProgramTimeout); 
    } 
    if((status == FLASH_COMPLETE) && (WRP2_Data != 0xFF)) 
    { 
      OB->WRP2 = WRP2_Data; 
       
      /* Wait for last operation to be completed */ 
      status = FLASH_WaitForLastOperation(ProgramTimeout); 
    } 
     
    if((status == FLASH_COMPLETE)&& (WRP3_Data != 0xFF)) 
    { 
      OB->WRP3 = WRP3_Data; 
      
      /* Wait for last operation to be completed */ 
      status = FLASH_WaitForLastOperation(ProgramTimeout); 
    } 
           
    if(status != FLASH_BUSY) 
    { 
      /* if the program operation is completed, disable the OPTPG Bit */ 
      FLASH->CR &= CR_OPTPG_Reset; 
    } 
  }  
  /* Return the write protection operation Status */ 
  return status;        
} 
 
/** 
  * @brief  Enables or disables the read out protection. 
  *   If the user has already programmed the other option bytes before  
  *   calling this function, he must re-program them since this  
  *   function erases all option bytes. 
  * @param Newstate: new state of the ReadOut Protection. 
  *   This parameter can be: ENABLE or DISABLE. 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT. 
  */ 
FLASH_Status FLASH_ReadOutProtection(FunctionalState NewState) 
{ 
  FLASH_Status status = FLASH_COMPLETE; 
  /* Check the parameters */ 
  assert_param(IS_FUNCTIONAL_STATE(NewState)); 
  status = FLASH_WaitForLastOperation(EraseTimeout); 
  if(status == FLASH_COMPLETE) 
  { 
    /* Authorizes the small information block programming */ 
    FLASH->OPTKEYR = FLASH_KEY1; 
    FLASH->OPTKEYR = FLASH_KEY2; 
    FLASH->CR |= CR_OPTER_Set; 
    FLASH->CR |= CR_STRT_Set; 
    /* Wait for last operation to be completed */ 
    status = FLASH_WaitForLastOperation(EraseTimeout); 
    if(status == FLASH_COMPLETE) 
    { 
      /* if the erase operation is completed, disable the OPTER Bit */ 
      FLASH->CR &= CR_OPTER_Reset; 
      /* Enable the Option Bytes Programming operation */ 
      FLASH->CR |= CR_OPTPG_Set;  
      if(NewState != DISABLE) 
      { 
        OB->RDP = 0x00; 
      } 
      else 
      { 
        OB->RDP = RDP_Key;   
      } 
      /* Wait for last operation to be completed */ 
      status = FLASH_WaitForLastOperation(EraseTimeout);  
     
      if(status != FLASH_BUSY) 
      { 
        /* if the program operation is completed, disable the OPTPG Bit */ 
        FLASH->CR &= CR_OPTPG_Reset; 
      } 
    } 
    else  
    { 
      if(status != FLASH_BUSY) 
      { 
        /* Disable the OPTER Bit */ 
        FLASH->CR &= CR_OPTER_Reset; 
      } 
    } 
  } 
  /* Return the protection operation Status */ 
  return status;       
} 
 
/** 
  * @brief  Programs the FLASH User Option Byte: IWDG_SW / RST_STOP / 
  *   RST_STDBY. 
  * @param OB_IWDG: Selects the IWDG mode 
  *   This parameter can be one of the following values: 
  * @arg OB_IWDG_SW: Software IWDG selected 
  * @arg OB_IWDG_HW: Hardware IWDG selected 
  * @param OB_STOP: Reset event when entering STOP mode. 
  *   This parameter can be one of the following values: 
  * @arg OB_STOP_NoRST: No reset generated when entering in STOP 
  * @arg OB_STOP_RST: Reset generated when entering in STOP 
  * @param OB_STDBY: Reset event when entering Standby mode. 
  *   This parameter can be one of the following values: 
  * @arg OB_STDBY_NoRST: No reset generated when entering in STANDBY 
  * @arg OB_STDBY_RST: Reset generated when entering in STANDBY 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT. 
  */ 
FLASH_Status FLASH_UserOptionByteConfig(uint16_t OB_IWDG, uint16_t OB_STOP, uint16_t OB_STDBY) 
{ 
  FLASH_Status status = FLASH_COMPLETE;  
  /* Check the parameters */ 
  assert_param(IS_OB_IWDG_SOURCE(OB_IWDG)); 
  assert_param(IS_OB_STOP_SOURCE(OB_STOP)); 
  assert_param(IS_OB_STDBY_SOURCE(OB_STDBY)); 
  /* Authorize the small information block programming */ 
  FLASH->OPTKEYR = FLASH_KEY1; 
  FLASH->OPTKEYR = FLASH_KEY2; 
   
  /* Wait for last operation to be completed */ 
  status = FLASH_WaitForLastOperation(ProgramTimeout); 
   
  if(status == FLASH_COMPLETE) 
  {   
    /* Enable the Option Bytes Programming operation */ 
    FLASH->CR |= CR_OPTPG_Set;  
            
    OB->USER = ( OB_IWDG | OB_STOP |OB_STDBY) | (uint16_t)0xF8;  
   
    /* Wait for last operation to be completed */ 
    status = FLASH_WaitForLastOperation(ProgramTimeout); 
    if(status != FLASH_BUSY) 
    { 
      /* if the program operation is completed, disable the OPTPG Bit */ 
      FLASH->CR &= CR_OPTPG_Reset; 
    } 
  }     
  /* Return the Option Byte program Status */ 
  return status; 
} 
 
/** 
  * @brief  Returns the FLASH User Option Bytes values. 
  * @param  None 
  * @retval : The FLASH User Option Bytes values:IWDG_SW(Bit0), RST_STOP(Bit1) 
  *   and RST_STDBY(Bit2). 
  */ 
uint32_t FLASH_GetUserOptionByte(void) 
{ 
  /* Return the User Option Byte */ 
  return (uint32_t)(FLASH->OBR >> 2); 
} 
 
/** 
  * @brief  Returns the FLASH Write Protection Option Bytes Register value. 
  * @param  None 
  * @retval : The FLASH Write Protection  Option Bytes Register value 
  */ 
uint32_t FLASH_GetWriteProtectionOptionByte(void) 
{ 
  /* Return the Falsh write protection Register value */ 
  return (uint32_t)(FLASH->WRPR); 
} 
 
/** 
  * @brief  Checks whether the FLASH Read Out Protection Status is set  
  *   or not. 
  * @param  None 
  * @retval : FLASH ReadOut Protection Status(SET or RESET) 
  */ 
FlagStatus FLASH_GetReadOutProtectionStatus(void) 
{ 
  FlagStatus readoutstatus = RESET; 
  if ((FLASH->OBR & RDPRT_Mask) != (uint32_t)RESET) 
  { 
    readoutstatus = SET; 
  } 
  else 
  { 
    readoutstatus = RESET; 
  } 
  return readoutstatus; 
} 
 
/** 
  * @brief  Checks whether the FLASH Prefetch Buffer status is set or not. 
  * @param  None 
  * @retval : FLASH Prefetch Buffer Status (SET or RESET). 
  */ 
FlagStatus FLASH_GetPrefetchBufferStatus(void) 
{ 
  FlagStatus bitstatus = RESET; 
   
  if ((FLASH->ACR & ACR_PRFTBS_Mask) != (uint32_t)RESET) 
  { 
    bitstatus = SET; 
  } 
  else 
  { 
    bitstatus = RESET; 
  } 
  /* Return the new state of FLASH Prefetch Buffer Status (SET or RESET) */ 
  return bitstatus;  
} 
 
/** 
  * @brief  Enables or disables the specified FLASH interrupts. 
  * @param FLASH_IT: specifies the FLASH interrupt sources to be  
  *   enabled or disabled. 
  *   This parameter can be any combination of the following values: 
  * @arg FLASH_IT_ERROR: FLASH Error Interrupt 
  * @arg FLASH_IT_EOP: FLASH end of operation Interrupt 
  * @param NewState: new state of the specified Flash interrupts. 
  *   This parameter can be: ENABLE or DISABLE.       
  * @retval : None  
  */ 
void FLASH_ITConfig(uint16_t FLASH_IT, FunctionalState NewState) 
{ 
  /* Check the parameters */ 
  assert_param(IS_FLASH_IT(FLASH_IT));  
  assert_param(IS_FUNCTIONAL_STATE(NewState)); 
  if(NewState != DISABLE) 
  { 
    /* Enable the interrupt sources */ 
    FLASH->CR |= FLASH_IT; 
  } 
  else 
  { 
    /* Disable the interrupt sources */ 
    FLASH->CR &= ~(uint32_t)FLASH_IT; 
  } 
} 
 
/** 
  * @brief  Checks whether the specified FLASH flag is set or not. 
  * @param FLASH_FLAG: specifies the FLASH flag to check. 
  *   This parameter can be one of the following values: 
  * @arg FLASH_FLAG_BSY: FLASH Busy flag            
  * @arg FLASH_FLAG_PGERR: FLASH Program error flag        
  * @arg FLASH_FLAG_WRPRTERR: FLASH Write protected error flag       
  * @arg FLASH_FLAG_EOP: FLASH End of Operation flag            
  * @arg FLASH_FLAG_OPTERR:  FLASH Option Byte error flag      
  * @retval : The new state of FLASH_FLAG (SET or RESET). 
  */ 
FlagStatus FLASH_GetFlagStatus(uint16_t FLASH_FLAG) 
{ 
  FlagStatus bitstatus = RESET; 
  /* Check the parameters */ 
  assert_param(IS_FLASH_GET_FLAG(FLASH_FLAG)) ; 
  if(FLASH_FLAG == FLASH_FLAG_OPTERR)  
  { 
    if((FLASH->OBR & FLASH_FLAG_OPTERR) != (uint32_t)RESET) 
    { 
      bitstatus = SET; 
    } 
    else 
    { 
      bitstatus = RESET; 
    } 
  } 
  else 
  { 
   if((FLASH->SR & FLASH_FLAG) != (uint32_t)RESET) 
    { 
      bitstatus = SET; 
    } 
    else 
    { 
      bitstatus = RESET; 
    } 
  } 
  /* Return the new state of FLASH_FLAG (SET or RESET) */ 
  return bitstatus; 
} 
 
/** 
  * @brief  Clears the FLASH’s pending flags. 
  * @param FLASH_FLAG: specifies the FLASH flags to clear. 
  *   This parameter can be any combination of the following values: 
  * @arg FLASH_FLAG_BSY: FLASH Busy flag            
  * @arg FLASH_FLAG_PGERR: FLASH Program error flag        
  * @arg FLASH_FLAG_WRPRTERR: FLASH Write protected error flag       
  * @arg FLASH_FLAG_EOP: FLASH End of Operation flag            
  * @retval : None 
  */ 
void FLASH_ClearFlag(uint16_t FLASH_FLAG) 
{ 
  /* Check the parameters */ 
  assert_param(IS_FLASH_CLEAR_FLAG(FLASH_FLAG)) ; 
   
  /* Clear the flags */ 
  FLASH->SR = FLASH_FLAG; 
} 
 
/** 
  * @brief  Returns the FLASH Status. 
  * @param  None 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP or FLASH_COMPLETE 
  */ 
FLASH_Status FLASH_GetStatus(void) 
{ 
  FLASH_Status flashstatus = FLASH_COMPLETE; 
   
  if((FLASH->SR & FLASH_FLAG_BSY) == FLASH_FLAG_BSY)  
  { 
    flashstatus = FLASH_BUSY; 
  } 
  else  
  {   
    if(FLASH->SR & FLASH_FLAG_PGERR) 
    {  
      flashstatus = FLASH_ERROR_PG; 
    } 
    else  
    { 
      if(FLASH->SR & FLASH_FLAG_WRPRTERR) 
      { 
        flashstatus = FLASH_ERROR_WRP; 
      } 
      else 
      { 
        flashstatus = FLASH_COMPLETE; 
      } 
    } 
  } 
  /* Return the Flash Status */ 
  return flashstatus; 
} 
 
/** 
  * @brief  Waits for a Flash operation to complete or a TIMEOUT to occur. 
  * @param Timeout: FLASH progamming Timeout 
  * @retval : FLASH Status: The returned value can be: FLASH_BUSY,  
  *   FLASH_ERROR_PG, FLASH_ERROR_WRP, FLASH_COMPLETE or  
  *   FLASH_TIMEOUT. 
  */ 
FLASH_Status FLASH_WaitForLastOperation(uint32_t Timeout) 
{  
  FLASH_Status status = FLASH_COMPLETE; 
    
  /* Check for the Flash Status */ 
  status = FLASH_GetStatus(); 
  /* Wait for a Flash operation to complete or a TIMEOUT to occur */ 
  while((status == FLASH_BUSY) && (Timeout != 0x00)) 
  { 
    delay(); 
    status = FLASH_GetStatus(); 
    Timeout--; 
  } 
  if(Timeout == 0x00 ) 
  { 
    status = FLASH_TIMEOUT; 
  } 
  /* Return the operation status */ 
  return status; 
} 
 
/** 
  * @brief  Inserts a time delay. 
  * @param  None 
  * @retval : None 
  */ 
static void delay(void) 
{ 
  __IO uint32_t i = 0; 
  for(i = 0xFF; i != 0; i--) 
  { 
  } 
} 
 
/** 
  * @} 
  */ 
 
/** 
  * @} 
  */ 
 
/** 
  * @} 
  */ 
 
/******************* (C) COPYRIGHT 2009 STMicroelectronics *****END OF FILE****/