--- /dev/null
+/**
+ ******************************************************************************
+ * @file stm32f4xx_iwdg.c
+ * @author MCD Application Team
+ * @version V1.0.0RC1
+ * @date 25-August-2011
+ * @brief This file provides firmware functions to manage the following
+ * functionalities of the Independent watchdog (IWDG) peripheral:
+ * - Prescaler and Counter configuration
+ * - IWDG activation
+ * - Flag management
+ *
+ * @verbatim
+ *
+ * ===================================================================
+ * IWDG features
+ * ===================================================================
+ *
+ * The IWDG can be started by either software or hardware (configurable
+ * through option byte).
+ *
+ * The IWDG is clocked by its own dedicated low-speed clock (LSI) and
+ * thus stays active even if the main clock fails.
+ * Once the IWDG is started, the LSI is forced ON and cannot be disabled
+ * (LSI cannot be disabled too), and the counter starts counting down from
+ * the reset value of 0xFFF. When it reaches the end of count value (0x000)
+ * a system reset is generated.
+ * The IWDG counter should be reloaded at regular intervals to prevent
+ * an MCU reset.
+ *
+ * The IWDG is implemented in the VDD voltage domain that is still functional
+ * in STOP and STANDBY mode (IWDG reset can wake-up from STANDBY).
+ *
+ * IWDGRST flag in RCC_CSR register can be used to inform when a IWDG
+ * reset occurs.
+ *
+ * Min-max timeout value @32KHz (LSI): ~125us / ~32.7s
+ * The IWDG timeout may vary due to LSI frequency dispersion. STM32F4xx
+ * devices provide the capability to measure the LSI frequency (LSI clock
+ * connected internally to TIM5 CH4 input capture). The measured value
+ * can be used to have an IWDG timeout with an acceptable accuracy.
+ * For more information, please refer to the STM32F4xx Reference manual
+ *
+ *
+ * ===================================================================
+ * How to use this driver
+ * ===================================================================
+ * 1. Enable write access to IWDG_PR and IWDG_RLR registers using
+ * IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable) function
+ *
+ * 2. Configure the IWDG prescaler using IWDG_SetPrescaler() function
+ *
+ * 3. Configure the IWDG counter value using IWDG_SetReload() function.
+ * This value will be loaded in the IWDG counter each time the counter
+ * is reloaded, then the IWDG will start counting down from this value.
+ *
+ * 4. Start the IWDG using IWDG_Enable() function, when the IWDG is used
+ * in software mode (no need to enable the LSI, it will be enabled
+ * by hardware)
+ *
+ * 5. Then the application program must reload the IWDG counter at regular
+ * intervals during normal operation to prevent an MCU reset, using
+ * IWDG_ReloadCounter() function.
+ *
+ * @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>© COPYRIGHT 2011 STMicroelectronics</center></h2>
+ ******************************************************************************
+ */
+
+/* Includes ------------------------------------------------------------------*/
+#include "stm32f4xx_iwdg.h"
+
+/** @addtogroup STM32F4xx_StdPeriph_Driver
+ * @{
+ */
+
+/** @defgroup IWDG
+ * @brief IWDG driver modules
+ * @{
+ */
+
+/* Private typedef -----------------------------------------------------------*/
+/* Private define ------------------------------------------------------------*/
+
+/* KR register bit mask */
+#define KR_KEY_RELOAD ((uint16_t)0xAAAA)
+#define KR_KEY_ENABLE ((uint16_t)0xCCCC)
+
+/* Private macro -------------------------------------------------------------*/
+/* Private variables ---------------------------------------------------------*/
+/* Private function prototypes -----------------------------------------------*/
+/* Private functions ---------------------------------------------------------*/
+
+/** @defgroup IWDG_Private_Functions
+ * @{
+ */
+
+/** @defgroup IWDG_Group1 Prescaler and Counter configuration functions
+ * @brief Prescaler and Counter configuration functions
+ *
+@verbatim
+ ===============================================================================
+ Prescaler and Counter configuration functions
+ ===============================================================================
+
+@endverbatim
+ * @{
+ */
+
+/**
+ * @brief Enables or disables write access to IWDG_PR and IWDG_RLR registers.
+ * @param IWDG_WriteAccess: new state of write access to IWDG_PR and IWDG_RLR registers.
+ * This parameter can be one of the following values:
+ * @arg IWDG_WriteAccess_Enable: Enable write access to IWDG_PR and IWDG_RLR registers
+ * @arg IWDG_WriteAccess_Disable: Disable write access to IWDG_PR and IWDG_RLR registers
+ * @retval None
+ */
+void IWDG_WriteAccessCmd(uint16_t IWDG_WriteAccess)
+{
+ /* Check the parameters */
+ assert_param(IS_IWDG_WRITE_ACCESS(IWDG_WriteAccess));
+ IWDG->KR = IWDG_WriteAccess;
+}
+
+/**
+ * @brief Sets IWDG Prescaler value.
+ * @param IWDG_Prescaler: specifies the IWDG Prescaler value.
+ * This parameter can be one of the following values:
+ * @arg IWDG_Prescaler_4: IWDG prescaler set to 4
+ * @arg IWDG_Prescaler_8: IWDG prescaler set to 8
+ * @arg IWDG_Prescaler_16: IWDG prescaler set to 16
+ * @arg IWDG_Prescaler_32: IWDG prescaler set to 32
+ * @arg IWDG_Prescaler_64: IWDG prescaler set to 64
+ * @arg IWDG_Prescaler_128: IWDG prescaler set to 128
+ * @arg IWDG_Prescaler_256: IWDG prescaler set to 256
+ * @retval None
+ */
+void IWDG_SetPrescaler(uint8_t IWDG_Prescaler)
+{
+ /* Check the parameters */
+ assert_param(IS_IWDG_PRESCALER(IWDG_Prescaler));
+ IWDG->PR = IWDG_Prescaler;
+}
+
+/**
+ * @brief Sets IWDG Reload value.
+ * @param Reload: specifies the IWDG Reload value.
+ * This parameter must be a number between 0 and 0x0FFF.
+ * @retval None
+ */
+void IWDG_SetReload(uint16_t Reload)
+{
+ /* Check the parameters */
+ assert_param(IS_IWDG_RELOAD(Reload));
+ IWDG->RLR = Reload;
+}
+
+/**
+ * @brief Reloads IWDG counter with value defined in the reload register
+ * (write access to IWDG_PR and IWDG_RLR registers disabled).
+ * @param None
+ * @retval None
+ */
+void IWDG_ReloadCounter(void)
+{
+ IWDG->KR = KR_KEY_RELOAD;
+}
+
+/**
+ * @}
+ */
+
+/** @defgroup IWDG_Group2 IWDG activation function
+ * @brief IWDG activation function
+ *
+@verbatim
+ ===============================================================================
+ IWDG activation function
+ ===============================================================================
+
+@endverbatim
+ * @{
+ */
+
+/**
+ * @brief Enables IWDG (write access to IWDG_PR and IWDG_RLR registers disabled).
+ * @param None
+ * @retval None
+ */
+void IWDG_Enable(void)
+{
+ IWDG->KR = KR_KEY_ENABLE;
+}
+
+/**
+ * @}
+ */
+
+/** @defgroup IWDG_Group3 Flag management function
+ * @brief Flag management function
+ *
+@verbatim
+ ===============================================================================
+ Flag management function
+ ===============================================================================
+
+@endverbatim
+ * @{
+ */
+
+/**
+ * @brief Checks whether the specified IWDG flag is set or not.
+ * @param IWDG_FLAG: specifies the flag to check.
+ * This parameter can be one of the following values:
+ * @arg IWDG_FLAG_PVU: Prescaler Value Update on going
+ * @arg IWDG_FLAG_RVU: Reload Value Update on going
+ * @retval The new state of IWDG_FLAG (SET or RESET).
+ */
+FlagStatus IWDG_GetFlagStatus(uint16_t IWDG_FLAG)
+{
+ FlagStatus bitstatus = RESET;
+ /* Check the parameters */
+ assert_param(IS_IWDG_FLAG(IWDG_FLAG));
+ if ((IWDG->SR & IWDG_FLAG) != (uint32_t)RESET)
+ {
+ bitstatus = SET;
+ }
+ else
+ {
+ bitstatus = RESET;
+ }
+ /* Return the flag status */
+ return bitstatus;
+}
+
+/**
+ * @}
+ */
+
+/**
+ * @}
+ */
+
+/**
+ * @}
+ */
+
+/**
+ * @}
+ */
+
+/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/
projects / fw / stlink / blobdiff