1 /**
2 ******************************************************************************
3 * @file stm32f4xx_hal_iwdg.c
4 * @author MCD Application Team
5 * @brief IWDG HAL module driver.
6 * This file provides firmware functions to manage the following
7 * functionalities of the Independent Watchdog (IWDG) peripheral:
8 * + Initialization and Start functions
9 * + IO operation functions
10 *
11 @verbatim
12 ==============================================================================
13 ##### IWDG Generic features #####
14 ==============================================================================
15 [..]
16 (+) The IWDG can be started by either software or hardware (configurable
17 through option byte).
18
19 (+) The IWDG is clocked by Low-Speed clock (LSI) and thus stays active even
20 if the main clock fails.
21
22 (+) Once the IWDG is started, the LSI is forced ON and both can not be
23 disabled. The counter starts counting down from the reset value (0xFFF).
24 When it reaches the end of count value (0x000) a reset signal is
25 generated (IWDG reset).
26
27 (+) Whenever the key value 0x0000 AAAA is written in the IWDG_KR register,
28 the IWDG_RLR value is reloaded in the counter and the watchdog reset is
29 prevented.
30
31 (+) The IWDG is implemented in the VDD voltage domain that is still functional
32 in STOP and STANDBY mode (IWDG reset can wake-up from STANDBY).
33 IWDGRST flag in RCC_CSR register can be used to inform when an IWDG
34 reset occurs.
35
36 (+) Debug mode : When the microcontroller enters debug mode (core halted),
37 the IWDG counter either continues to work normally or stops, depending
38 on DBG_IWDG_STOP configuration bit in DBG module, accessible through
39 __HAL_DBGMCU_FREEZE_IWDG() and __HAL_DBGMCU_UNFREEZE_IWDG() macros.
40
41 [..] Min-max timeout value @32KHz (LSI): ~125us / ~32.7s
42 The IWDG timeout may vary due to LSI frequency dispersion. STM32F4xx
43 devices provide the capability to measure the LSI frequency (LSI clock
44 connected internally to TIM5 CH4 input capture). The measured value
45 can be used to have an IWDG timeout with an acceptable accuracy.
46
47 ##### How to use this driver #####
48 ==============================================================================
49 [..]
50 (#) Use IWDG using HAL_IWDG_Init() function to :
51 (++) Enable instance by writing Start keyword in IWDG_KEY register. LSI
52 clock is forced ON and IWDG counter starts counting down.
53 (++) Enable write access to configuration registers:
54 IWDG_PR and IWDG_RLR.
55 (++) Configure the IWDG prescaler and counter reload value. This reload
56 value will be loaded in the IWDG counter each time the watchdog is
57 reloaded, then the IWDG will start counting down from this value.
58 (++) Wait for status flags to be reset.
59
60 (#) Then the application program must refresh the IWDG counter at regular
61 intervals during normal operation to prevent an MCU reset, using
62 HAL_IWDG_Refresh() function.
63
64 *** IWDG HAL driver macros list ***
65 ====================================
66 [..]
67 Below the list of most used macros in IWDG HAL driver:
68 (+) __HAL_IWDG_START: Enable the IWDG peripheral
69 (+) __HAL_IWDG_RELOAD_COUNTER: Reloads IWDG counter with value defined in
70 the reload register
71
72 @endverbatim
73 ******************************************************************************
74 * @attention
75 *
76 * <h2><center>© Copyright (c) 2016 STMicroelectronics.
77 * All rights reserved.</center></h2>
78 *
79 * This software component is licensed by ST under BSD 3-Clause license,
80 * the "License"; You may not use this file except in compliance with the
81 * License. You may obtain a copy of the License at:
82 * opensource.org/licenses/BSD-3-Clause
83 *
84 ******************************************************************************
85 */
86
87 /* Includes ------------------------------------------------------------------*/
88 #include "stm32f4xx_hal.h"
89
90 /** @addtogroup STM32F4xx_HAL_Driver
91 * @{
92 */
93
94 #ifdef HAL_IWDG_MODULE_ENABLED
95 /** @addtogroup IWDG
96 * @brief IWDG HAL module driver.
97 * @{
98 */
99
100 /* Private typedef -----------------------------------------------------------*/
101 /* Private define ------------------------------------------------------------*/
102 /** @defgroup IWDG_Private_Defines IWDG Private Defines
103 * @{
104 */
105 /* Status register need 5 RC LSI divided by prescaler clock to be updated. With
106 higher prescaler (256), and according to LSI variation, we need to wait at
107 least 6 cycles so 48 ms. */
108 #define HAL_IWDG_DEFAULT_TIMEOUT 48u
109 /**
110 * @}
111 */
112
113 /* Private macro -------------------------------------------------------------*/
114 /* Private variables ---------------------------------------------------------*/
115 /* Private function prototypes -----------------------------------------------*/
116 /* Exported functions --------------------------------------------------------*/
117
118 /** @addtogroup IWDG_Exported_Functions
119 * @{
120 */
121
122 /** @addtogroup IWDG_Exported_Functions_Group1
123 * @brief Initialization and Start functions.
124 *
125 @verbatim
126 ===============================================================================
127 ##### Initialization and Start functions #####
128 ===============================================================================
129 [..] This section provides functions allowing to:
130 (+) Initialize the IWDG according to the specified parameters in the
131 IWDG_InitTypeDef of associated handle.
132 (+) Once initialization is performed in HAL_IWDG_Init function, Watchdog
133 is reloaded in order to exit function with correct time base.
134
135 @endverbatim
136 * @{
137 */
138
139 /**
140 * @brief Initialize the IWDG according to the specified parameters in the
141 * IWDG_InitTypeDef and start watchdog. Before exiting function,
142 * watchdog is refreshed in order to have correct time base.
143 * @param hiwdg pointer to a IWDG_HandleTypeDef structure that contains
144 * the configuration information for the specified IWDG module.
145 * @retval HAL status
146 */
HAL_IWDG_Init(IWDG_HandleTypeDef * hiwdg)147 HAL_StatusTypeDef HAL_IWDG_Init(IWDG_HandleTypeDef *hiwdg)
148 {
149 uint32_t tickstart;
150
151 /* Check the IWDG handle allocation */
152 if (hiwdg == NULL)
153 {
154 return HAL_ERROR;
155 }
156
157 /* Check the parameters */
158 assert_param(IS_IWDG_ALL_INSTANCE(hiwdg->Instance));
159 assert_param(IS_IWDG_PRESCALER(hiwdg->Init.Prescaler));
160 assert_param(IS_IWDG_RELOAD(hiwdg->Init.Reload));
161
162 /* Enable IWDG. LSI is turned on automatically */
163 __HAL_IWDG_START(hiwdg);
164
165 /* Enable write access to IWDG_PR and IWDG_RLR registers by writing
166 0x5555 in KR */
167 IWDG_ENABLE_WRITE_ACCESS(hiwdg);
168
169 /* Write to IWDG registers the Prescaler & Reload values to work with */
170 hiwdg->Instance->PR = hiwdg->Init.Prescaler;
171 hiwdg->Instance->RLR = hiwdg->Init.Reload;
172
173 /* Check pending flag, if previous update not done, return timeout */
174 tickstart = HAL_GetTick();
175
176 /* Wait for register to be updated */
177 while (hiwdg->Instance->SR != 0x00u)
178 {
179 if ((HAL_GetTick() - tickstart) > HAL_IWDG_DEFAULT_TIMEOUT)
180 {
181 return HAL_TIMEOUT;
182 }
183 }
184
185 /* Reload IWDG counter with value defined in the reload register */
186 __HAL_IWDG_RELOAD_COUNTER(hiwdg);
187
188 /* Return function status */
189 return HAL_OK;
190 }
191
192 /**
193 * @}
194 */
195
196
197 /** @addtogroup IWDG_Exported_Functions_Group2
198 * @brief IO operation functions
199 *
200 @verbatim
201 ===============================================================================
202 ##### IO operation functions #####
203 ===============================================================================
204 [..] This section provides functions allowing to:
205 (+) Refresh the IWDG.
206
207 @endverbatim
208 * @{
209 */
210
211
212 /**
213 * @brief Refresh the IWDG.
214 * @param hiwdg pointer to a IWDG_HandleTypeDef structure that contains
215 * the configuration information for the specified IWDG module.
216 * @retval HAL status
217 */
HAL_IWDG_Refresh(IWDG_HandleTypeDef * hiwdg)218 HAL_StatusTypeDef HAL_IWDG_Refresh(IWDG_HandleTypeDef *hiwdg)
219 {
220 /* Reload IWDG counter with value defined in the reload register */
221 __HAL_IWDG_RELOAD_COUNTER(hiwdg);
222
223 /* Return function status */
224 return HAL_OK;
225 }
226
227 /**
228 * @}
229 */
230
231 /**
232 * @}
233 */
234
235 #endif /* HAL_IWDG_MODULE_ENABLED */
236 /**
237 * @}
238 */
239
240 /**
241 * @}
242 */
243
244 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
245