stm8l15x_wwdg.c

STM8L的tim4定时器使用

/**
  ********************************************************************************
  * @file    stm8l15x_wwdg.c
  * @author  MCD Application Team
  * @version V1.5.0
  * @date    13-May-2011
  * @brief   This file provides firmware functions to manage the following 
  *          functionalities of the Window watchdog (WWDG) peripheral:           
  *           - Refresh window and Counter configuration
  *           - WWDG activation
  *           - Couter and software reset management
  *             
  *  @verbatim
  *    
  *          ===================================================================
  *                                     WWDG features
  *          ===================================================================
  *                                        
  *          Once enabled the WWDG generates a system reset on expiry of a programmed
  *          time period, unless the program refreshes the counter (downcounter) 
  *          before to reach 0x3F value (i.e. a reset is generated when the counter
  *          value rolls over from 0x40 to 0x3F). 
  *          An MCU reset is also generated if the counter value is refreshed
  *          before the counter has reached the refresh window value. This 
  *          implies that the counter must be refreshed in a limited window.
  *            
  *          Once enabled the WWDG cannot be disabled except by a system reset.
  *          
  *          If the WWDG is activated and the watchdog reset on halt option is 
  *          selected (Option byte), then the HALT instruction will generate a reset.                               
  *          
  *          WWDGF flag in RST_SR register can be used to inform when a WWDG
  *          reset occurs.
  *            
  *          WWDG timeout = (WWDG counter clock) * 12288 * (T[5:0] + 1)
  *                      
  *          Min-max timeout value @16 MHz(PCLK1): ~0.768 ms / ~49.152 ms
  *                            
  *          ===================================================================
  *                                 How to use this driver
  *          =================================================================== 
  *          1. Configure the WWDG refresh window using WWDG_SetWindowValue() function
  *            
  *          2. Set the WWDG counter value and start it using WWDG_Enable() function.
  *             When the WWDG is enabled the counter value should be configured to 
  *             a value greater than 0x40 to prevent generating an immediate reset.     
  *            
  *          3. Then the application program must refresh the WWDG counter at regular
  *             intervals during normal operation to prevent an MCU reset, using
  *             WWDG_SetCounter() function. This operation must occur only when
  *             the counter value is lower than the refresh window value, 
  *             programmed using WWDG_SetWindowValue().         
  *
  *  @endverbatim  
  *                             
  ******************************************************************************
  * @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 "stm8l15x_wwdg.h"

/** @addtogroup STM8L15x_StdPeriph_Driver
  * @{
  */
/** @defgroup WWDG 
  * @brief WWDG driver modules
  * @{
  */
  
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define BIT_MASK          ((uint8_t)0x7F)
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

/** @defgroup WWDG_Private_Functions
  * @{
  */
  
/** @defgroup WWDG_Group1 Refresh window and Counter configuration functions
 *  @brief   Refresh window and Counter configuration functions 
 *
@verbatim   
 ===============================================================================
              Refresh window and Counter configuration functions
 ===============================================================================  

@endverbatim
  * @{
  */
  
/**
  * @brief  Initializes the WWDG peripheral.
  *         This function set Window Register = WindowValue, Counter Register
  *         according to Counter and \b ENABLE \b WWDG
  * @param  Counter : WWDG counter value
  * @param  WindowValue : specifies the WWDG Window Register, range is 0x00 to 0x7F.
  * @retval None
  */
void WWDG_Init(uint8_t Counter, uint8_t WindowValue)
{
  /* Check the parameters */
  assert_param(IS_WWDG_WINDOW_LIMIT_VALUE(WindowValue));
  
  WWDG->WR = WWDG_WR_RESET_VALUE;
  WWDG->CR = (uint8_t)(WWDG_CR_WDGA | Counter);
  WWDG->WR = (uint8_t)((uint8_t)BIT_MASK & (uint8_t) WindowValue);
}

/**
  * @brief  Sets the WWDG window value.
  * @param  WindowValue: specifies the window value to be compared to the downcounter.
  *         This parameter value must be lower than 0x80.
  * @retval None
  */
void WWDG_SetWindowValue(uint8_t WindowValue)
{
  __IO uint8_t tmpreg = 0;

  /* Check the parameters */
  assert_param(IS_WWDG_WINDOW_LIMIT_VALUE(WindowValue));

  /* Set W[6:0] bits according to WindowValue value */
  tmpreg |= (uint8_t) (WindowValue & (uint8_t) BIT_MASK);

  /* Store the new value */
  WWDG->WR = tmpreg;
}

/**
  * @brief  Sets the WWDG counter value.
  * @param  Counter: specifies the watchdog counter value.
  *   This parameter must be a number between 0x40 and 0x7F (to prevent generating
  *   an immediate reset) 
  * @retval None
  */
void WWDG_SetCounter(uint8_t Counter)
{
  /* Check the parameters */
  assert_param(IS_WWDG_COUNTER_VALUE(Counter));

  /* Write to T[6:0] bits to configure the counter value, no need to do
     a read-modify-write; writing a 0 to WDGA bit does nothing */
  WWDG->CR = (uint8_t)(Counter & (uint8_t)BIT_MASK);
}
/**
  * @}
  */

/** @defgroup WWDG_Group2 WWDG activation function 
 *  @brief   WWDG activation function  
 *
@verbatim   
 ===============================================================================
                          WWDG activation function 
 ===============================================================================  

@endverbatim
  * @{
  */
  
/**
  * @brief  Enables WWDG and load the counter value.
  * @param  Counter: specifies the watchdog counter value.
  *         This parameter must be a number between 0x40 and 0x7F.
  * @retval None
  */
void WWDG_Enable(uint8_t Counter)
{
  /* Check the parameters */
  assert_param(IS_WWDG_COUNTER_VALUE(Counter));
  WWDG->CR = (uint8_t)(WWDG_CR_WDGA | Counter);
}

/**
  * @}
  */

/** @defgroup WWDG_Group3 WWDG counter and software reset management 
 *  @brief   WWDG counter and software reset management
 *
@verbatim   
 ===============================================================================
                   WWDG counter and software reset management 
 ===============================================================================  

@endverbatim
  * @{
  */
/**
  * @brief Gets the WWDG Counter Value.
  *        This value could be used to check if WWDG is in the window, where
  *        refresh is allowed.
  * @param  None
  * @retval WWDG Counter Value
  */
uint8_t WWDG_GetCounter(void)
{
  return(WWDG->CR);
}

/**
  * @brief Generates immediate WWDG RESET.
  * @param  None
  * @retval None
  */
void WWDG_SWReset(void)
{
  WWDG->CR = WWDG_CR_WDGA; /* Activate WWDG, with clearing T6 */
}

/**
  * @}
  */

/**
  * @}
  */
  
/**
  * @}
  */

/**
  * @}
  */

/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/