/**
  ******************************************************************************
  * @file    CortexM/BitBand/main.c 
  * @author  MCD Application Team
  * @version V1.3.0
  * @date    13-November-2013
  * @brief   Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT 2013 STMicroelectronics</center></h2>
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32f4xx.h"

/** @addtogroup STM32F4xx_StdPeriph_Examples
  * @{
  */

/** @addtogroup CortexM_BitBand
  * @{
  */ 

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
#define  Var_ResetBit_BB(VarAddr, BitNumber)    \
          (*(__IO uint32_t *) (SRAM_BB_BASE | ((VarAddr - SRAM_BASE) << 5) | ((BitNumber) << 2)) = 0)
   
#define Var_SetBit_BB(VarAddr, BitNumber)       \
          (*(__IO uint32_t *) (SRAM_BB_BASE | ((VarAddr - SRAM_BASE) << 5) | ((BitNumber) << 2)) = 1)

#define Var_GetBit_BB(VarAddr, BitNumber)       \
          (*(__IO uint32_t *) (SRAM_BB_BASE | ((VarAddr - SRAM_BASE) << 5) | ((BitNumber) << 2)))
          
/* Private variables ---------------------------------------------------------*/
__IO uint32_t Var, VarAddr = 0, VarBitValue = 0;

/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /*!< At this stage the microcontroller clock setting is already configured, 
       this is done through SystemInit() function which is called from startup
       files (startup_stm32f40_41xxx.s/startup_stm32f427_437xx.s/startup_stm32f429_439xx.s)
       before to branch to application main. 
       To reconfigure the default setting of SystemInit() function, refer to
       system_stm32f4xx.c file
     */     
       
  Var = 0x00005AA5;

/* A mapping formula shows how to reference each word in the alias region to a 
   corresponding bit in the bit-band region. The mapping formula is:
   bit_word_addr = bit_band_base + (byte_offset x 32) + (bit_number + 4)

where:
   - bit_word_addr: is the address of the word in the alias memory region that 
                    maps to the targeted bit.
   - bit_band_base is the starting address of the alias region
   - byte_offset is the number of the byte in the bit-band region that contains 
     the targeted bit
   - bit_number is the bit position (0-7) of the targeted bit */

/* Get the variable address --------------------------------------------------*/ 
  VarAddr = (uint32_t)&Var; 

/* Modify variable bit using bit-band access ---------------------------------*/
  /* Modify Var variable bit 0 -----------------------------------------------*/
  Var_ResetBit_BB(VarAddr, 0);  /* Var = 0x00005AA4 */
  Var_SetBit_BB(VarAddr, 0);    /* Var = 0x00005AA5 */
  
  /* Modify Var variable bit 11 ----------------------------------------------*/
  Var_ResetBit_BB(VarAddr, 11);             /* Var = 0x000052A5 */
  /* Get Var variable bit 11 value */
  VarBitValue = Var_GetBit_BB(VarAddr, 11); /* VarBitValue = 0x00000000 */
  
  Var_SetBit_BB(VarAddr, 11);               /* Var = 0x00005AA5 */
  /* Get Var variable bit 11 value */
  VarBitValue = Var_GetBit_BB(VarAddr, 11);    /* VarBitValue = 0x00000001 */
  
  /* Modify Var variable bit 31 ----------------------------------------------*/
  Var_SetBit_BB(VarAddr, 31);               /* Var = 0x80005AA5 */
  /* Get Var variable bit 31 value */
  VarBitValue = Var_GetBit_BB(VarAddr, 31); /* VarBitValue = 0x00000001 */
    
  Var_ResetBit_BB(VarAddr, 31);             /* Var = 0x00005AA5 */
  /* Get Var variable bit 31 value */
  VarBitValue = Var_GetBit_BB(VarAddr, 31); /* VarBitValue = 0x00000000 */
        
  while (1)
  {
  }
}

#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 STMicroelectronics *****END OF FILE****/
