lib/main/STM32F3/Drivers/STM32F30x_StdPeriph_Driver/src/stm32f30x_wwdg.c

   1 /**
   2   ******************************************************************************
   3   * @file    stm32f30x_wwdg.c
   4   * @author  MCD Application Team
   5   * @version V1.1.1
   6   * @date    04-April-2014
   7   * @brief   This file provides firmware functions to manage the following
   8   *          functionalities of the Window watchdog (WWDG) peripheral:
   9   *           + Prescaler, Refresh window and Counter configuration
  10   *           + WWDG activation
  11   *           + Interrupts and flags management
  12   *
  13   *  @verbatim
  14   *
  15   ==============================================================================
  16                            ##### WWDG features #####
  17   ==============================================================================
  18
  19     [..] Once enabled the WWDG generates a system reset on expiry of a programmed
  20         time period, unless the program refreshes the counter (downcounter)
  21         before to reach 0x3F value (i.e. a reset is generated when the counter
  22         value rolls over from 0x40 to 0x3F).
  23     [..] An MCU reset is also generated if the counter value is refreshed
  24         before the counter has reached the refresh window value. This
  25         implies that the counter must be refreshed in a limited window.
  26
  27     [..] Once enabled the WWDG cannot be disabled except by a system reset.
  28
  29     [..] WWDGRST flag in RCC_CSR register can be used to inform when a WWDG
  30         reset occurs.
  31
  32     [..] The WWDG counter input clock is derived from the APB clock divided
  33         by a programmable prescaler.
  34
  35     [..] WWDG counter clock = PCLK1 / Prescaler.
  36     [..] WWDG timeout = (WWDG counter clock) * (counter value).
  37
  38     [..] Min-max timeout value @36MHz (PCLK1): ~114us / ~58.3ms.
  39
  40                      ##### How to use this driver #####
  41   ==============================================================================
  42     [..]
  43           (#) Enable WWDG clock using RCC_APB1PeriphClockCmd(RCC_APB1Periph_WWDG, ENABLE)
  44               function.
  45
  46           (#) Configure the WWDG prescaler using WWDG_SetPrescaler() function.
  47
  48           (#) Configure the WWDG refresh window using WWDG_SetWindowValue() function.
  49
  50           (#) Set the WWDG counter value and start it using WWDG_Enable() function.
  51              When the WWDG is enabled the counter value should be configured to
  52              a value greater than 0x40 to prevent generating an immediate reset.
  53
  54           (#) Optionally you can enable the Early wakeup interrupt which is
  55              generated when the counter reach 0x40.
  56              Once enabled this interrupt cannot be disabled except by a system reset.
  57
  58           (#) Then the application program must refresh the WWDG counter at regular
  59              intervals during normal operation to prevent an MCU reset, using
  60              WWDG_SetCounter() function. This operation must occur only when
  61              the counter value is lower than the refresh window value,
  62              programmed using WWDG_SetWindowValue().
  63
  64   @endverbatim
  65
  66   ******************************************************************************
  67   * @attention
  68   *
  69   * <h2><center>&copy; COPYRIGHT 2014 STMicroelectronics</center></h2>
  70   *
  71   * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  72   * You may not use this file except in compliance with the License.
  73   * You may obtain a copy of the License at:
  74   *
  75   *        http://www.st.com/software_license_agreement_liberty_v2
  76   *
  77   * Unless required by applicable law or agreed to in writing, software
  78   * distributed under the License is distributed on an "AS IS" BASIS,
  79   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  80   * See the License for the specific language governing permissions and
  81   * limitations under the License.
  82   *
  83   ******************************************************************************
  84   */
  85
  86 /* Includes ------------------------------------------------------------------*/
  87 #include "stm32f30x_wwdg.h"
  88 #include "stm32f30x_rcc.h"
  89
  90 /** @addtogroup STM32F30x_StdPeriph_Driver
  91   * @{
  92   */
  93
  94 /** @defgroup WWDG
  95   * @brief WWDG driver modules
  96   * @{
  97   */
  98
  99 /* Private typedef -----------------------------------------------------------*/
 100 /* Private define ------------------------------------------------------------*/
 101 /* --------------------- WWDG registers bit mask ---------------------------- */
 102 /* CFR register bit mask */
 103 #define CFR_WDGTB_MASK    ((uint32_t)0xFFFFFE7F)
 104 #define CFR_W_MASK        ((uint32_t)0xFFFFFF80)
 105 #define BIT_MASK          ((uint8_t)0x7F)
 106
 107 /* Private macro -------------------------------------------------------------*/
 108 /* Private variables ---------------------------------------------------------*/
 109 /* Private function prototypes -----------------------------------------------*/
 110 /* Private functions ---------------------------------------------------------*/
 111
 112 /** @defgroup WWDG_Private_Functions
 113   * @{
 114   */
 115
 116 /** @defgroup WWDG_Group1 Prescaler, Refresh window and Counter configuration functions
 117  *  @brief   Prescaler, Refresh window and Counter configuration functions
 118  *
 119 @verbatim
 120   ==============================================================================
 121     ##### Prescaler, Refresh window and Counter configuration functions #####
 122   ==============================================================================
 123
 124 @endverbatim
 125   * @{
 126   */
 127
 128 /**
 129   * @brief  Deinitializes the WWDG peripheral registers to their default reset values.
 130   * @param  None
 131   * @retval None
 132   */
 133 void WWDG_DeInit(void)
 134 {
 135   RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, ENABLE);
 136   RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, DISABLE);
 137 }
 138
 139 /**
 140   * @brief  Sets the WWDG Prescaler.
 141   * @param  WWDG_Prescaler: specifies the WWDG Prescaler.
 142   *   This parameter can be one of the following values:
 143   *     @arg WWDG_Prescaler_1: WWDG counter clock = (PCLK1/4096)/1
 144   *     @arg WWDG_Prescaler_2: WWDG counter clock = (PCLK1/4096)/2
 145   *     @arg WWDG_Prescaler_4: WWDG counter clock = (PCLK1/4096)/4
 146   *     @arg WWDG_Prescaler_8: WWDG counter clock = (PCLK1/4096)/8
 147   * @retval None
 148   */
 149 void WWDG_SetPrescaler(uint32_t WWDG_Prescaler)
 150 {
 151   uint32_t tmpreg = 0;
 152   /* Check the parameters */
 153   assert_param(IS_WWDG_PRESCALER(WWDG_Prescaler));
 154   /* Clear WDGTB[1:0] bits */
 155   tmpreg = WWDG->CFR & CFR_WDGTB_MASK;
 156   /* Set WDGTB[1:0] bits according to WWDG_Prescaler value */
 157   tmpreg |= WWDG_Prescaler;
 158   /* Store the new value */
 159   WWDG->CFR = tmpreg;
 160 }
 161
 162 /**
 163   * @brief  Sets the WWDG window value.
 164   * @param  WindowValue: specifies the window value to be compared to the downcounter.
 165   *   This parameter value must be lower than 0x80.
 166   * @retval None
 167   */
 168 void WWDG_SetWindowValue(uint8_t WindowValue)
 169 {
 170   __IO uint32_t tmpreg = 0;
 171
 172   /* Check the parameters */
 173   assert_param(IS_WWDG_WINDOW_VALUE(WindowValue));
 174   /* Clear W[6:0] bits */
 175
 176   tmpreg = WWDG->CFR & CFR_W_MASK;
 177
 178   /* Set W[6:0] bits according to WindowValue value */
 179   tmpreg |= WindowValue & (uint32_t) BIT_MASK;
 180
 181   /* Store the new value */
 182   WWDG->CFR = tmpreg;
 183 }
 184
 185 /**
 186   * @brief  Enables the WWDG Early Wakeup interrupt(EWI).
 187   * @note   Once enabled this interrupt cannot be disabled except by a system reset.
 188   * @param  None
 189   * @retval None
 190   */
 191 void WWDG_EnableIT(void)
 192 {
 193   WWDG->CFR |= WWDG_CFR_EWI;
 194 }
 195
 196 /**
 197   * @brief  Sets the WWDG counter value.
 198   * @param  Counter: specifies the watchdog counter value.
 199   *   This parameter must be a number between 0x40 and 0x7F (to prevent generating
 200   *   an immediate reset).
 201   * @retval None
 202   */
 203 void WWDG_SetCounter(uint8_t Counter)
 204 {
 205   /* Check the parameters */
 206   assert_param(IS_WWDG_COUNTER(Counter));
 207   /* Write to T[6:0] bits to configure the counter value, no need to do
 208      a read-modify-write; writing a 0 to WDGA bit does nothing */
 209   WWDG->CR = Counter & BIT_MASK;
 210 }
 211
 212 /**
 213   * @}
 214   */
 215
 216 /** @defgroup WWDG_Group2 WWDG activation functions
 217  *  @brief   WWDG activation functions
 218  *
 219 @verbatim
 220   ==============================================================================
 221                     ##### WWDG activation function #####
 222   ==============================================================================
 223
 224 @endverbatim
 225   * @{
 226   */
 227
 228 /**
 229   * @brief  Enables WWDG and load the counter value.
 230   * @param  Counter: specifies the watchdog counter value.
 231   *   This parameter must be a number between 0x40 and 0x7F (to prevent generating
 232   *   an immediate reset).
 233   * @retval None
 234   */
 235 void WWDG_Enable(uint8_t Counter)
 236 {
 237   /* Check the parameters */
 238   assert_param(IS_WWDG_COUNTER(Counter));
 239   WWDG->CR = WWDG_CR_WDGA | Counter;
 240 }
 241
 242 /**
 243   * @}
 244   */
 245
 246 /** @defgroup WWDG_Group3 Interrupts and flags management functions
 247  *  @brief   Interrupts and flags management functions
 248  *
 249 @verbatim
 250   ==============================================================================
 251               ##### Interrupts and flags management functions #####
 252   ==============================================================================
 253
 254 @endverbatim
 255   * @{
 256   */
 257
 258 /**
 259   * @brief  Checks whether the Early Wakeup interrupt flag is set or not.
 260   * @param  None
 261   * @retval The new state of the Early Wakeup interrupt flag (SET or RESET).
 262   */
 263 FlagStatus WWDG_GetFlagStatus(void)
 264 {
 265   FlagStatus bitstatus = RESET;
 266
 267   if ((WWDG->SR) != (uint32_t)RESET)
 268   {
 269     bitstatus = SET;
 270   }
 271   else
 272   {
 273     bitstatus = RESET;
 274   }
 275   return bitstatus;
 276 }
 277
 278 /**
 279   * @brief  Clears Early Wakeup interrupt flag.
 280   * @param  None
 281   * @retval None
 282   */
 283 void WWDG_ClearFlag(void)
 284 {
 285   WWDG->SR = (uint32_t)RESET;
 286 }
 287
 288 /**
 289   * @}
 290   */
 291
 292 /**
 293   * @}
 294   */
 295
 296 /**
 297   * @}
 298   */
 299
 300 /**
 301   * @}
 302   */
 303
 304 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/