lib/main/STM32F4/Drivers/STM32F4xx_StdPeriph_Driver/src/stm32f4xx_wwdg.c

   1 /**
   2   ******************************************************************************
   3   * @file    stm32f4xx_wwdg.c
   4   * @author  MCD Application Team
   5   * @version V1.7.1
   6   * @date    20-May-2016
   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                            ##### WWDG features #####
  16  ===============================================================================
  17     [..]
  18         Once enabled the WWDG generates a system reset on expiry of a programmed
  19         time period, unless the program refreshes the counter (downcounter)
  20         before to reach 0x3F value (i.e. a reset is generated when the counter
  21         value rolls over from 0x40 to 0x3F).
  22         An MCU reset is also generated if the counter value is refreshed
  23         before the counter has reached the refresh window value. This
  24         implies that the counter must be refreshed in a limited window.
  25
  26         Once enabled the WWDG cannot be disabled except by a system reset.
  27
  28         WWDGRST flag in RCC_CSR register can be used to inform when a WWDG
  29         reset occurs.
  30
  31         The WWDG counter input clock is derived from the APB clock divided
  32         by a programmable prescaler.
  33
  34         WWDG counter clock = PCLK1 / Prescaler
  35         WWDG timeout = (WWDG counter clock) * (counter value)
  36
  37         Min-max timeout value @42 MHz(PCLK1): ~97.5 us / ~49.9 ms
  38
  39                       ##### How to use this driver #####
  40  ===============================================================================
  41     [..]
  42       (#) Enable WWDG clock using RCC_APB1PeriphClockCmd(RCC_APB1Periph_WWDG, ENABLE) function
  43
  44       (#) Configure the WWDG prescaler using WWDG_SetPrescaler() function
  45
  46       (#) Configure the WWDG refresh window using WWDG_SetWindowValue() function
  47
  48       (#) Set the WWDG counter value and start it using WWDG_Enable() function.
  49           When the WWDG is enabled the counter value should be configured to
  50           a value greater than 0x40 to prevent generating an immediate reset.
  51
  52       (#) Optionally you can enable the Early wakeup interrupt which is
  53           generated when the counter reach 0x40.
  54           Once enabled this interrupt cannot be disabled except by a system reset.
  55
  56       (#) Then the application program must refresh the WWDG counter at regular
  57           intervals during normal operation to prevent an MCU reset, using
  58           WWDG_SetCounter() function. This operation must occur only when
  59           the counter value is lower than the refresh window value,
  60           programmed using WWDG_SetWindowValue().
  61
  62     @endverbatim
  63   ******************************************************************************
  64   * @attention
  65   *
  66   * <h2><center>&copy; COPYRIGHT 2016 STMicroelectronics</center></h2>
  67   *
  68   * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  69   * You may not use this file except in compliance with the License.
  70   * You may obtain a copy of the License at:
  71   *
  72   *        http://www.st.com/software_license_agreement_liberty_v2
  73   *
  74   * Unless required by applicable law or agreed to in writing, software
  75   * distributed under the License is distributed on an "AS IS" BASIS,
  76   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  77   * See the License for the specific language governing permissions and
  78   * limitations under the License.
  79   *
  80   ******************************************************************************
  81   */
  82
  83 /* Includes ------------------------------------------------------------------*/
  84 #include "stm32f4xx_wwdg.h"
  85 #include "stm32f4xx_rcc.h"
  86
  87 /** @addtogroup STM32F4xx_StdPeriph_Driver
  88   * @{
  89   */
  90
  91 /** @defgroup WWDG
  92   * @brief WWDG driver modules
  93   * @{
  94   */
  95
  96 /* Private typedef -----------------------------------------------------------*/
  97 /* Private define ------------------------------------------------------------*/
  98
  99 /* ----------- WWDG registers bit address in the alias region ----------- */
 100 #define WWDG_OFFSET       (WWDG_BASE - PERIPH_BASE)
 101 /* Alias word address of EWI bit */
 102 #define CFR_OFFSET        (WWDG_OFFSET + 0x04)
 103 #define EWI_BitNumber     0x09
 104 #define CFR_EWI_BB        (PERIPH_BB_BASE + (CFR_OFFSET * 32) + (EWI_BitNumber * 4))
 105
 106 /* --------------------- WWDG registers bit mask ------------------------ */
 107 /* CFR register bit mask */
 108 #define CFR_WDGTB_MASK    ((uint32_t)0xFFFFFE7F)
 109 #define CFR_W_MASK        ((uint32_t)0xFFFFFF80)
 110 #define BIT_MASK          ((uint8_t)0x7F)
 111
 112 /* Private macro -------------------------------------------------------------*/
 113 /* Private variables ---------------------------------------------------------*/
 114 /* Private function prototypes -----------------------------------------------*/
 115 /* Private functions ---------------------------------------------------------*/
 116
 117 /** @defgroup WWDG_Private_Functions
 118   * @{
 119   */
 120
 121 /** @defgroup WWDG_Group1 Prescaler, Refresh window and Counter configuration functions
 122  *  @brief   Prescaler, Refresh window and Counter configuration functions
 123  *
 124 @verbatim
 125  ===============================================================================
 126     ##### Prescaler, Refresh window and Counter configuration functions #####
 127  ===============================================================================
 128
 129 @endverbatim
 130   * @{
 131   */
 132
 133 /**
 134   * @brief  Deinitializes the WWDG peripheral registers to their default reset values.
 135   * @param  None
 136   * @retval None
 137   */
 138 void WWDG_DeInit(void)
 139 {
 140   RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, ENABLE);
 141   RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, DISABLE);
 142 }
 143
 144 /**
 145   * @brief  Sets the WWDG Prescaler.
 146   * @param  WWDG_Prescaler: specifies the WWDG Prescaler.
 147   *   This parameter can be one of the following values:
 148   *     @arg WWDG_Prescaler_1: WWDG counter clock = (PCLK1/4096)/1
 149   *     @arg WWDG_Prescaler_2: WWDG counter clock = (PCLK1/4096)/2
 150   *     @arg WWDG_Prescaler_4: WWDG counter clock = (PCLK1/4096)/4
 151   *     @arg WWDG_Prescaler_8: WWDG counter clock = (PCLK1/4096)/8
 152   * @retval None
 153   */
 154 void WWDG_SetPrescaler(uint32_t WWDG_Prescaler)
 155 {
 156   uint32_t tmpreg = 0;
 157   /* Check the parameters */
 158   assert_param(IS_WWDG_PRESCALER(WWDG_Prescaler));
 159   /* Clear WDGTB[1:0] bits */
 160   tmpreg = WWDG->CFR & CFR_WDGTB_MASK;
 161   /* Set WDGTB[1:0] bits according to WWDG_Prescaler value */
 162   tmpreg |= WWDG_Prescaler;
 163   /* Store the new value */
 164   WWDG->CFR = tmpreg;
 165 }
 166
 167 /**
 168   * @brief  Sets the WWDG window value.
 169   * @param  WindowValue: specifies the window value to be compared to the downcounter.
 170   *   This parameter value must be lower than 0x80.
 171   * @retval None
 172   */
 173 void WWDG_SetWindowValue(uint8_t WindowValue)
 174 {
 175   __IO uint32_t tmpreg = 0;
 176
 177   /* Check the parameters */
 178   assert_param(IS_WWDG_WINDOW_VALUE(WindowValue));
 179   /* Clear W[6:0] bits */
 180
 181   tmpreg = WWDG->CFR & CFR_W_MASK;
 182
 183   /* Set W[6:0] bits according to WindowValue value */
 184   tmpreg |= WindowValue & (uint32_t) BIT_MASK;
 185
 186   /* Store the new value */
 187   WWDG->CFR = tmpreg;
 188 }
 189
 190 /**
 191   * @brief  Enables the WWDG Early Wakeup interrupt(EWI).
 192   * @note   Once enabled this interrupt cannot be disabled except by a system reset.
 193   * @param  None
 194   * @retval None
 195   */
 196 void WWDG_EnableIT(void)
 197 {
 198   *(__IO uint32_t *) CFR_EWI_BB = (uint32_t)ENABLE;
 199 }
 200
 201 /**
 202   * @brief  Sets the WWDG counter value.
 203   * @param  Counter: specifies the watchdog counter value.
 204   *   This parameter must be a number between 0x40 and 0x7F (to prevent generating
 205   *   an immediate reset)
 206   * @retval None
 207   */
 208 void WWDG_SetCounter(uint8_t Counter)
 209 {
 210   /* Check the parameters */
 211   assert_param(IS_WWDG_COUNTER(Counter));
 212   /* Write to T[6:0] bits to configure the counter value, no need to do
 213      a read-modify-write; writing a 0 to WDGA bit does nothing */
 214   WWDG->CR = Counter & BIT_MASK;
 215 }
 216 /**
 217   * @}
 218   */
 219
 220 /** @defgroup WWDG_Group2 WWDG activation functions
 221  *  @brief   WWDG activation functions
 222  *
 223 @verbatim
 224  ===============================================================================
 225                     ##### WWDG activation function #####
 226  ===============================================================================
 227
 228 @endverbatim
 229   * @{
 230   */
 231
 232 /**
 233   * @brief  Enables WWDG and load the counter value.
 234   * @param  Counter: specifies the watchdog counter value.
 235   *   This parameter must be a number between 0x40 and 0x7F (to prevent generating
 236   *   an immediate reset)
 237   * @retval None
 238   */
 239 void WWDG_Enable(uint8_t Counter)
 240 {
 241   /* Check the parameters */
 242   assert_param(IS_WWDG_COUNTER(Counter));
 243   WWDG->CR = WWDG_CR_WDGA | Counter;
 244 }
 245 /**
 246   * @}
 247   */
 248
 249 /** @defgroup WWDG_Group3 Interrupts and flags management functions
 250  *  @brief   Interrupts and flags management functions
 251  *
 252 @verbatim
 253  ===============================================================================
 254             ##### Interrupts and flags management functions #####
 255  ===============================================================================
 256
 257 @endverbatim
 258   * @{
 259   */
 260
 261 /**
 262   * @brief  Checks whether the Early Wakeup interrupt flag is set or not.
 263   * @param  None
 264   * @retval The new state of the Early Wakeup interrupt flag (SET or RESET)
 265   */
 266 FlagStatus WWDG_GetFlagStatus(void)
 267 {
 268   FlagStatus bitstatus = RESET;
 269
 270   if ((WWDG->SR) != (uint32_t)RESET)
 271   {
 272     bitstatus = SET;
 273   }
 274   else
 275   {
 276     bitstatus = RESET;
 277   }
 278   return bitstatus;
 279 }
 280
 281 /**
 282   * @brief  Clears Early Wakeup interrupt flag.
 283   * @param  None
 284   * @retval None
 285   */
 286 void WWDG_ClearFlag(void)
 287 {
 288   WWDG->SR = (uint32_t)RESET;
 289 }
 290
 291 /**
 292   * @}
 293   */
 294
 295 /**
 296   * @}
 297   */
 298
 299 /**
 300   * @}
 301   */
 302
 303 /**
 304   * @}
 305   */
 306
 307 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/