stm32f30x_wwdg.c

00001 /**
00002   ******************************************************************************
00003   * @file    stm32f30x_wwdg.c
00004   * @author  MCD Application Team
00005   * @version V1.2.3
00006   * @date    10-July-2015
00007   * @brief   This file provides firmware functions to manage the following 
00008   *          functionalities of the Window watchdog (WWDG) peripheral:
00009   *           + Prescaler, Refresh window and Counter configuration
00010   *           + WWDG activation
00011   *           + Interrupts and flags management
00012   *             
00013   *  @verbatim
00014   *    
00015   ==============================================================================
00016                            ##### WWDG features #####
00017   ==============================================================================
00018                                         
00019     [..] Once enabled the WWDG generates a system reset on expiry of a programmed
00020         time period, unless the program refreshes the counter (downcounter) 
00021         before to reach 0x3F value (i.e. a reset is generated when the counter
00022         value rolls over from 0x40 to 0x3F). 
00023     [..] An MCU reset is also generated if the counter value is refreshed
00024         before the counter has reached the refresh window value. This 
00025         implies that the counter must be refreshed in a limited window.
00026             
00027     [..] Once enabled the WWDG cannot be disabled except by a system reset.
00028          
00029     [..] WWDGRST flag in RCC_CSR register can be used to inform when a WWDG
00030         reset occurs.
00031             
00032     [..] The WWDG counter input clock is derived from the APB clock divided 
00033         by a programmable prescaler.
00034               
00035     [..] WWDG counter clock = PCLK1 / Prescaler.
00036     [..] WWDG timeout = (WWDG counter clock) * (counter value).
00037                      
00038     [..] Min-max timeout value @36MHz (PCLK1): ~114us / ~58.3ms. 
00039 
00040                      ##### How to use this driver #####
00041   ============================================================================== 
00042     [..]         
00043           (#) Enable WWDG clock using RCC_APB1PeriphClockCmd(RCC_APB1Periph_WWDG, ENABLE) 
00044               function.
00045             
00046           (#) Configure the WWDG prescaler using WWDG_SetPrescaler() function.
00047                            
00048           (#) Configure the WWDG refresh window using WWDG_SetWindowValue() function.
00049             
00050           (#) Set the WWDG counter value and start it using WWDG_Enable() function.
00051              When the WWDG is enabled the counter value should be configured to 
00052              a value greater than 0x40 to prevent generating an immediate reset.     
00053             
00054           (#) Optionally you can enable the Early wakeup interrupt which is 
00055              generated when the counter reach 0x40.
00056              Once enabled this interrupt cannot be disabled except by a system reset.
00057                  
00058           (#) Then the application program must refresh the WWDG counter at regular
00059              intervals during normal operation to prevent an MCU reset, using
00060              WWDG_SetCounter() function. This operation must occur only when
00061              the counter value is lower than the refresh window value, 
00062              programmed using WWDG_SetWindowValue().         
00063 
00064   @endverbatim  
00065                              
00066   ******************************************************************************
00067   * @attention
00068   *
00069   * <h2><center>&copy; COPYRIGHT 2015 STMicroelectronics</center></h2>
00070   *
00071   * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
00072   * You may not use this file except in compliance with the License.
00073   * You may obtain a copy of the License at:
00074   *
00075   *        http://www.st.com/software_license_agreement_liberty_v2
00076   *
00077   * Unless required by applicable law or agreed to in writing, software 
00078   * distributed under the License is distributed on an "AS IS" BASIS, 
00079   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00080   * See the License for the specific language governing permissions and
00081   * limitations under the License.
00082   *
00083   ******************************************************************************
00084   */
00085 
00086 /* Includes ------------------------------------------------------------------*/
00087 #include "stm32f30x_wwdg.h"
00088 #include "stm32f30x_rcc.h"
00089 
00090 /** @addtogroup STM32F30x_StdPeriph_Driver
00091   * @{
00092   */
00093 
00094 /** @defgroup WWDG 
00095   * @brief WWDG driver modules
00096   * @{
00097   */
00098 
00099 /* Private typedef -----------------------------------------------------------*/
00100 /* Private define ------------------------------------------------------------*/
00101 /* --------------------- WWDG registers bit mask ---------------------------- */
00102 /* CFR register bit mask */
00103 #define CFR_WDGTB_MASK    ((uint32_t)0xFFFFFE7F)
00104 #define CFR_W_MASK        ((uint32_t)0xFFFFFF80)
00105 #define BIT_MASK          ((uint8_t)0x7F)
00106 
00107 /* Private macro -------------------------------------------------------------*/
00108 /* Private variables ---------------------------------------------------------*/
00109 /* Private function prototypes -----------------------------------------------*/
00110 /* Private functions ---------------------------------------------------------*/
00111 
00112 /** @defgroup WWDG_Private_Functions
00113   * @{
00114   */
00115 
00116 /** @defgroup WWDG_Group1 Prescaler, Refresh window and Counter configuration functions
00117  *  @brief   Prescaler, Refresh window and Counter configuration functions 
00118  *
00119 @verbatim   
00120   ==============================================================================
00121     ##### Prescaler, Refresh window and Counter configuration functions #####
00122   ==============================================================================  
00123 
00124 @endverbatim
00125   * @{
00126   */
00127 
00128 /**
00129   * @brief  Deinitializes the WWDG peripheral registers to their default reset values.
00130   * @param  None
00131   * @retval None
00132   */
00133 void WWDG_DeInit(void)
00134 {
00135   RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, ENABLE);
00136   RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, DISABLE);
00137 }
00138 
00139 /**
00140   * @brief  Sets the WWDG Prescaler.
00141   * @param  WWDG_Prescaler: specifies the WWDG Prescaler.
00142   *   This parameter can be one of the following values:
00143   *     @arg WWDG_Prescaler_1: WWDG counter clock = (PCLK1/4096)/1
00144   *     @arg WWDG_Prescaler_2: WWDG counter clock = (PCLK1/4096)/2
00145   *     @arg WWDG_Prescaler_4: WWDG counter clock = (PCLK1/4096)/4
00146   *     @arg WWDG_Prescaler_8: WWDG counter clock = (PCLK1/4096)/8
00147   * @retval None
00148   */
00149 void WWDG_SetPrescaler(uint32_t WWDG_Prescaler)
00150 {
00151   uint32_t tmpreg = 0;
00152   /* Check the parameters */
00153   assert_param(IS_WWDG_PRESCALER(WWDG_Prescaler));
00154   /* Clear WDGTB[1:0] bits */
00155   tmpreg = WWDG->CFR & CFR_WDGTB_MASK;
00156   /* Set WDGTB[1:0] bits according to WWDG_Prescaler value */
00157   tmpreg |= WWDG_Prescaler;
00158   /* Store the new value */
00159   WWDG->CFR = tmpreg;
00160 }
00161 
00162 /**
00163   * @brief  Sets the WWDG window value.
00164   * @param  WindowValue: specifies the window value to be compared to the downcounter.
00165   *   This parameter value must be lower than 0x80.
00166   * @retval None
00167   */
00168 void WWDG_SetWindowValue(uint8_t WindowValue)
00169 {
00170   __IO uint32_t tmpreg = 0;
00171 
00172   /* Check the parameters */
00173   assert_param(IS_WWDG_WINDOW_VALUE(WindowValue));
00174   /* Clear W[6:0] bits */
00175 
00176   tmpreg = WWDG->CFR & CFR_W_MASK;
00177 
00178   /* Set W[6:0] bits according to WindowValue value */
00179   tmpreg |= WindowValue & (uint32_t) BIT_MASK;
00180 
00181   /* Store the new value */
00182   WWDG->CFR = tmpreg;
00183 }
00184 
00185 /**
00186   * @brief  Enables the WWDG Early Wakeup interrupt(EWI).
00187   * @note   Once enabled this interrupt cannot be disabled except by a system reset. 
00188   * @param  None
00189   * @retval None
00190   */
00191 void WWDG_EnableIT(void)
00192 {
00193   WWDG->CFR |= WWDG_CFR_EWI;
00194 }
00195 
00196 /**
00197   * @brief  Sets the WWDG counter value.
00198   * @param  Counter: specifies the watchdog counter value.
00199   *   This parameter must be a number between 0x40 and 0x7F (to prevent generating
00200   *   an immediate reset).  
00201   * @retval None
00202   */
00203 void WWDG_SetCounter(uint8_t Counter)
00204 {
00205   /* Check the parameters */
00206   assert_param(IS_WWDG_COUNTER(Counter));
00207   /* Write to T[6:0] bits to configure the counter value, no need to do
00208      a read-modify-write; writing a 0 to WDGA bit does nothing */
00209   WWDG->CR = Counter & BIT_MASK;
00210 }
00211 
00212 /**
00213   * @}
00214   */
00215 
00216 /** @defgroup WWDG_Group2 WWDG activation functions
00217  *  @brief   WWDG activation functions 
00218  *
00219 @verbatim   
00220   ==============================================================================
00221                     ##### WWDG activation function #####
00222   ==============================================================================  
00223 
00224 @endverbatim
00225   * @{
00226   */
00227 
00228 /**
00229   * @brief  Enables WWDG and load the counter value.                  
00230   * @param  Counter: specifies the watchdog counter value.
00231   *   This parameter must be a number between 0x40 and 0x7F (to prevent generating
00232   *   an immediate reset).
00233   * @retval None
00234   */
00235 void WWDG_Enable(uint8_t Counter)
00236 {
00237   /* Check the parameters */
00238   assert_param(IS_WWDG_COUNTER(Counter));
00239   WWDG->CR = WWDG_CR_WDGA | Counter;
00240 }
00241 
00242 /**
00243   * @}
00244   */
00245 
00246 /** @defgroup WWDG_Group3 Interrupts and flags management functions
00247  *  @brief   Interrupts and flags management functions 
00248  *
00249 @verbatim   
00250   ==============================================================================
00251               ##### Interrupts and flags management functions #####
00252   ==============================================================================  
00253 
00254 @endverbatim
00255   * @{
00256   */
00257 
00258 /**
00259   * @brief  Checks whether the Early Wakeup interrupt flag is set or not.
00260   * @param  None
00261   * @retval The new state of the Early Wakeup interrupt flag (SET or RESET).
00262   */
00263 FlagStatus WWDG_GetFlagStatus(void)
00264 {
00265   FlagStatus bitstatus = RESET;
00266     
00267   if ((WWDG->SR) != (uint32_t)RESET)
00268   {
00269     bitstatus = SET;
00270   }
00271   else
00272   {
00273     bitstatus = RESET;
00274   }
00275   return bitstatus;
00276 }
00277 
00278 /**
00279   * @brief  Clears Early Wakeup interrupt flag.
00280   * @param  None
00281   * @retval None
00282   */
00283 void WWDG_ClearFlag(void)
00284 {
00285   WWDG->SR = (uint32_t)RESET;
00286 }
00287 
00288 /**
00289   * @}
00290   */
00291 
00292 /**
00293   * @}
00294   */
00295 
00296 /**
00297   * @}
00298   */
00299 
00300 /**
00301   * @}
00302   */
00303 
00304 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/