text: /**
    ******************************************************************************
    * @file    stm8s_awu.c
    * @author  MCD Application Team
    * @version V2.0.0
    * @date    25-February-2011
    * @brief   This file contains all the functions for the AWU peripheral.  
    ******************************************************************************
    * @attention
    *
    * 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 2011 STMicroelectronics</center></h2>
    ******************************************************************************
    */
  
  /* Includes ------------------------------------------------------------------*/
  #include "stm8s_awu.h"
  
  /** @addtogroup STM8S_StdPeriph_Driver
    * @{
    */
  /* Private typedef -----------------------------------------------------------*/
  /* Private define ------------------------------------------------------------*/
  /* Private macro -------------------------------------------------------------*/
  /* Private variables ---------------------------------------------------------*/
  /* Private function prototypes -----------------------------------------------*/
  /* Private functions ---------------------------------------------------------*/
  
  /* See also AWU_Timebase_TypeDef structure in stm8s_awu.h file :
                            N   2   5   1   2   4   8   1   3   6   1   2   5   1   2   1   3
                            O   5   0   m   m   m   m   6   2   4   2   5   1   s   s   2   0
                            I   0   0   s   s   s   s   m   m   m   8   6   2           s   s
                            T   u   u                   s   s   s   m   m   m
                                s   s                               s   s   s
  */
  /** Contains the different values to write in the APR register (used by AWU_Init function) */
  CONST uint8_t APR_Array[17] =
      {
          0, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 61, 23, 23, 62
      };
  
  /** Contains the different values to write in the TBR register (used by AWU_Init function) */
  CONST uint8_t TBR_Array[17] =
      {
          0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 12, 14, 15, 15
      };
  
  /* Public functions ----------------------------------------------------------*/
  
  /**
    * @addtogroup AWU_Public_Functions
    * @{
    */
  
  /**
    * @brief  Deinitializes the AWU peripheral registers to their default reset
    * values.
    * @param  None
    * @retval None
    */
  void AWU_DeInit(void)
  {
      AWU->CSR = AWU_CSR_RESET_VALUE;
      AWU->APR = AWU_APR_RESET_VALUE;
      AWU->TBR = AWU_TBR_RESET_VALUE;
  }
  
  /**
    * @brief  Initializes the AWU peripheral according to the specified parameters.
    * @param   AWU_TimeBase : Time base selection (interval between AWU interrupts).
    * can be one of the values of @ref AWU_Timebase_TypeDef.
    * @retval None
    * @par Required preconditions:
    * The LS RC calibration must be performed before calling this function.
    */
  void AWU_Init(AWU_Timebase_TypeDef AWU_TimeBase)
  {
  
      /* Check parameter */
      assert_param(IS_AWU_TIMEBASE_OK(AWU_TimeBase));
  
      /* Enable the AWU peripheral */
      AWU->CSR |= AWU_CSR_AWUEN;
  
      /* Set the TimeBase */
      AWU->TBR &= (uint8_t)(~AWU_TBR_AWUTB);
      AWU->TBR |= TBR_Array[(uint8_t)AWU_TimeBase];
  
      /* Set the APR divider */
      AWU->APR &= (uint8_t)(~AWU_APR_APR);
      AWU->APR |= APR_Array[(uint8_t)AWU_TimeBase];
  
  }
  
  /**
    * @brief  Enable or disable the AWU peripheral.
    * @param   NewState Indicates the new state of the AWU peripheral.
    * @retval None
    * @par Required preconditions:
    * Initialisation of AWU and LS RC calibration must be done before.
    */
  void AWU_Cmd(FunctionalState NewState)
  {
      if (NewState != DISABLE)
      {
          /* Enable the AWU peripheral */
          AWU->CSR |= AWU_CSR_AWUEN;
      }
      else
      {
          /* Disable the AWU peripheral */
          AWU->CSR &= (uint8_t)(~AWU_CSR_AWUEN);
      }
  }
  
  /**
    * @brief  Update APR register with the measured LSI frequency.
    * @par Note on the APR calculation:
    * A is the integer part of lsifreqkhz/4 and x the decimal part.
    * x <= A/(1+2A) is equivalent to A >= x(1+2A) and also to 4A >= 4x(1+2A) [F1]
    * but we know that A + x = lsifreqkhz/4 ==> 4x = lsifreqkhz-4A
    * so [F1] can be written :
    * 4A >= (lsifreqkhz-4A)(1+2A)
    * @param   LSIFreqHz Low Speed RC frequency measured by timer (in Hz).
    * @retval None
    * @par Required preconditions:
    * - AWU must be disabled to avoid unwanted interrupts.
    */
  void AWU_LSICalibrationConfig(uint32_t LSIFreqHz)
  {
  
      uint16_t lsifreqkhz = 0x0;
      uint16_t A = 0x0;
  
      /* Check parameter */
      assert_param(IS_LSI_FREQUENCY_OK(LSIFreqHz));
  
      lsifreqkhz = (uint16_t)(LSIFreqHz / 1000); /* Converts value in kHz */
  
      /* Calculation of AWU calibration value */
  
      A = (uint16_t)(lsifreqkhz >> 2U); /* Division by 4, keep integer part only */
  
      if ((4U * A) >= ((lsifreqkhz - (4U * A)) * (1U + (2U * A))))
      {
          AWU->APR = (uint8_t)(A - 2U);
      }
      else
      {
          AWU->APR = (uint8_t)(A - 1U);
      }
  }
  
  /**
    * @brief  Configures AWU in Idle mode to reduce power consumption.
    * @param  None
    * @retval None
    */
  void AWU_IdleModeEnable(void)
  {
      /* Disable AWU peripheral */
      AWU->CSR &= (uint8_t)(~AWU_CSR_AWUEN);
  
      /* No AWU timebase */
      AWU->TBR = (uint8_t)(~AWU_TBR_AWUTB);
  }
  
  /**
    * @brief  Returns status of the AWU peripheral flag.
    * @param  None
    * @retval FlagStatus : Status of the AWU flag.
    * This parameter can be any of the @ref FlagStatus enumeration.
    */
  FlagStatus AWU_GetFlagStatus(void)
  {
      return((FlagStatus)(((uint8_t)(AWU->CSR & AWU_CSR_AWUF) == (uint8_t)0x00) ? RESET : SET));
  }
  
  
  /**
    * @}
    */
    
  /**
    * @}
    */
    
  /******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/
  