1 /**
2 ******************************************************************************
3 * @file stm32h7xx_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 ******************************************************************************
12 * @attention
13 *
14 * Copyright (c) 2017 STMicroelectronics.
15 * All rights reserved.
16 *
17 * This software is licensed under terms that can be found in the LICENSE file
18 * in the root directory of this software component.
19 * If no LICENSE file comes with this software, it is provided AS-IS.
20 *
21 ******************************************************************************
22 @verbatim
23 ==============================================================================
24 ##### IWDG Generic features #####
25 ==============================================================================
26 [..]
27 (+) The IWDG can be started by either software or hardware (configurable
28 through option byte).
29
30 (+) The IWDG is clocked by the Low-Speed Internal clock (LSI) and thus stays
31 active even if the main clock fails.
32
33 (+) Once the IWDG is started, the LSI is forced ON and both cannot be
34 disabled. The counter starts counting down from the reset value (0xFFF).
35 When it reaches the end of count value (0x000) a reset signal is
36 generated (IWDG reset).
37
38 (+) Whenever the key value 0x0000 AAAA is written in the IWDG_KR register,
39 the IWDG_RLR value is reloaded into the counter and the watchdog reset
40 is prevented.
41
42 (+) The IWDG is implemented in the VDD voltage domain that is still functional
43 in STOP and STANDBY mode (IWDG reset can wake up the CPU from STANDBY).
44 IWDGRST flag in RCC_CSR register can be used to inform when an IWDG
45 reset occurs.
46
47 (+) Debug mode: When the microcontroller enters debug mode (core halted),
48 the IWDG counter either continues to work normally or stops, depending
49 on DBG_IWDG_STOP configuration bit in DBG module, accessible through
50 __HAL_DBGMCU_FREEZE_IWDG1() or __HAL_DBGMCU_FREEZE2_IWDG2() and
51 __HAL_DBGMCU_UnFreeze_IWDG1 or __HAL_DBGMCU_UnFreeze2_IWDG2() macros.
52
53 [..] Min-max timeout value @32KHz (LSI): ~125us / ~32.7s
54 The IWDG timeout may vary due to LSI clock frequency dispersion.
55 STM32H7xx devices provide the capability to measure the LSI clock
56 frequency (LSI clock is internally connected to TIM16 CH1 input capture).
57 The measured value can be used to have an IWDG timeout with an
58 acceptable accuracy.
59
60 [..] Default timeout value (necessary for IWDG_SR status register update):
61 Constant LSI_VALUE is defined based on the nominal LSI clock frequency.
62 This frequency being subject to variations as mentioned above, the
63 default timeout value (defined through constant HAL_IWDG_DEFAULT_TIMEOUT
64 below) may become too short or too long.
65 In such cases, this default timeout value can be tuned by redefining
66 the constant LSI_VALUE at user-application level (based, for instance,
67 on the measured LSI clock frequency as explained above).
68
69 ##### How to use this driver #####
70 ==============================================================================
71 [..]
72 (#) Use IWDG using HAL_IWDG_Init() function to :
73 (++) Enable instance by writing Start keyword in IWDG_KEY register. LSI
74 clock is forced ON and IWDG counter starts counting down.
75 (++) Enable write access to configuration registers:
76 IWDG_PR, IWDG_RLR and IWDG_WINR.
77 (++) Configure the IWDG prescaler and counter reload value. This reload
78 value will be loaded in the IWDG counter each time the watchdog is
79 reloaded, then the IWDG will start counting down from this value.
80 (++) Depending on window parameter:
81 (+++) If Window Init parameter is same as Window register value,
82 nothing more is done but reload counter value in order to exit
83 function with exact time base.
84 (+++) Else modify Window register. This will automatically reload
85 watchdog counter.
86 (++) Wait for status flags to be reset.
87
88 (#) Then the application program must refresh the IWDG counter at regular
89 intervals during normal operation to prevent an MCU reset, using
90 HAL_IWDG_Refresh() function.
91
92 *** IWDG HAL driver macros list ***
93 ====================================
94 [..]
95 Below the list of most used macros in IWDG HAL driver:
96 (+) __HAL_IWDG_START: Enable the IWDG peripheral
97 (+) __HAL_IWDG_RELOAD_COUNTER: Reloads IWDG counter with value defined in
98 the reload register
99
100 @endverbatim
101 */
102
103 /* Includes ------------------------------------------------------------------*/
104 #include "stm32h7xx_hal.h"
105
106 /** @addtogroup STM32H7xx_HAL_Driver
107 * @{
108 */
109
110 #ifdef HAL_IWDG_MODULE_ENABLED
111 /** @addtogroup IWDG
112 * @brief IWDG HAL module driver.
113 * @{
114 */
115
116 /* Private typedef -----------------------------------------------------------*/
117 /* Private define ------------------------------------------------------------*/
118 /** @defgroup IWDG_Private_Defines IWDG Private Defines
119 * @{
120 */
121 /* Status register needs up to 5 LSI clock periods divided by the clock
122 prescaler to be updated. The number of LSI clock periods is upper-rounded to
123 6 for the timeout value calculation.
124 The timeout value is calculated using the highest prescaler (256) and
125 the LSI_VALUE constant. The value of this constant can be changed by the user
126 to take into account possible LSI clock period variations.
127 The timeout value is multiplied by 1000 to be converted in milliseconds.
128 LSI startup time is also considered here by adding LSI_STARTUP_TIME
129 converted in milliseconds. */
130 #define HAL_IWDG_DEFAULT_TIMEOUT (((6UL * 256UL * 1000UL) / LSI_VALUE) + ((LSI_STARTUP_TIME / 1000UL) + 1UL))
131 #define IWDG_KERNEL_UPDATE_FLAGS (IWDG_SR_WVU | IWDG_SR_RVU | IWDG_SR_PVU)
132 /**
133 * @}
134 */
135
136 /* Private macro -------------------------------------------------------------*/
137 /* Private variables ---------------------------------------------------------*/
138 /* Private function prototypes -----------------------------------------------*/
139 /* Exported functions --------------------------------------------------------*/
140
141 /** @addtogroup IWDG_Exported_Functions
142 * @{
143 */
144
145 /** @addtogroup IWDG_Exported_Functions_Group1
146 * @brief Initialization and Start functions.
147 *
148 @verbatim
149 ===============================================================================
150 ##### Initialization and Start functions #####
151 ===============================================================================
152 [..] This section provides functions allowing to:
153 (+) Initialize the IWDG according to the specified parameters in the
154 IWDG_InitTypeDef of associated handle.
155 (+) Manage Window option.
156 (+) Once initialization is performed in HAL_IWDG_Init function, Watchdog
157 is reloaded in order to exit function with correct time base.
158
159 @endverbatim
160 * @{
161 */
162
163 /**
164 * @brief Initialize the IWDG according to the specified parameters in the
165 * IWDG_InitTypeDef and start watchdog. Before exiting function,
166 * watchdog is refreshed in order to have correct time base.
167 * @param hiwdg pointer to a IWDG_HandleTypeDef structure that contains
168 * the configuration information for the specified IWDG module.
169 * @retval HAL status
170 */
HAL_IWDG_Init(IWDG_HandleTypeDef * hiwdg)171 HAL_StatusTypeDef HAL_IWDG_Init(IWDG_HandleTypeDef *hiwdg)
172 {
173 uint32_t tickstart;
174
175 /* Check the IWDG handle allocation */
176 if (hiwdg == NULL)
177 {
178 return HAL_ERROR;
179 }
180
181 /* Check the parameters */
182 assert_param(IS_IWDG_ALL_INSTANCE(hiwdg->Instance));
183 assert_param(IS_IWDG_PRESCALER(hiwdg->Init.Prescaler));
184 assert_param(IS_IWDG_RELOAD(hiwdg->Init.Reload));
185 assert_param(IS_IWDG_WINDOW(hiwdg->Init.Window));
186
187 /* Enable IWDG. LSI is turned on automatically */
188 __HAL_IWDG_START(hiwdg);
189
190 /* Enable write access to IWDG_PR, IWDG_RLR and IWDG_WINR registers by writing
191 0x5555 in KR */
192 IWDG_ENABLE_WRITE_ACCESS(hiwdg);
193
194 /* Write to IWDG registers the Prescaler & Reload values to work with */
195 hiwdg->Instance->PR = hiwdg->Init.Prescaler;
196 hiwdg->Instance->RLR = hiwdg->Init.Reload;
197
198 /* Check pending flag, if previous update not done, return timeout */
199 tickstart = HAL_GetTick();
200
201 /* Wait for register to be updated */
202 while ((hiwdg->Instance->SR & IWDG_KERNEL_UPDATE_FLAGS) != 0x00u)
203 {
204 if ((HAL_GetTick() - tickstart) > HAL_IWDG_DEFAULT_TIMEOUT)
205 {
206 if ((hiwdg->Instance->SR & IWDG_KERNEL_UPDATE_FLAGS) != 0x00u)
207 {
208 return HAL_TIMEOUT;
209 }
210 }
211 }
212
213 /* If window parameter is different than current value, modify window
214 register */
215 if (hiwdg->Instance->WINR != hiwdg->Init.Window)
216 {
217 /* Write to IWDG WINR the IWDG_Window value to compare with. In any case,
218 even if window feature is disabled, Watchdog will be reloaded by writing
219 windows register */
220 hiwdg->Instance->WINR = hiwdg->Init.Window;
221 }
222 else
223 {
224 /* Reload IWDG counter with value defined in the reload register */
225 __HAL_IWDG_RELOAD_COUNTER(hiwdg);
226 }
227
228 /* Return function status */
229 return HAL_OK;
230 }
231
232
233 /**
234 * @}
235 */
236
237
238 /** @addtogroup IWDG_Exported_Functions_Group2
239 * @brief IO operation functions
240 *
241 @verbatim
242 ===============================================================================
243 ##### IO operation functions #####
244 ===============================================================================
245 [..] This section provides functions allowing to:
246 (+) Refresh the IWDG.
247
248 @endverbatim
249 * @{
250 */
251
252 /**
253 * @brief Refresh the IWDG.
254 * @param hiwdg pointer to a IWDG_HandleTypeDef structure that contains
255 * the configuration information for the specified IWDG module.
256 * @retval HAL status
257 */
HAL_IWDG_Refresh(IWDG_HandleTypeDef * hiwdg)258 HAL_StatusTypeDef HAL_IWDG_Refresh(IWDG_HandleTypeDef *hiwdg)
259 {
260 /* Reload IWDG counter with value defined in the reload register */
261 __HAL_IWDG_RELOAD_COUNTER(hiwdg);
262
263 /* Return function status */
264 return HAL_OK;
265 }
266
267
268 /**
269 * @}
270 */
271
272 /**
273 * @}
274 */
275
276 #endif /* HAL_IWDG_MODULE_ENABLED */
277 /**
278 * @}
279 */
280
281 /**
282 * @}
283 */
284
