stm8s_awu.c
/**
  ******************************************************************************
  * @file    stm8s_awu.c
  * @author  MCD Application Team
  * @version V2.2.0
  * @date    30-September-2014
  * @brief   This file contains all the functions for the AWU peripheral.  
   ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT 2014 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 "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 STMicroelectronics *****END OF FILE****/