1 /**
2 ******************************************************************************
3 * @file stm32l5xx_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 the Low-Speed Internal clock (LSI) and thus stays
20 active even if the main clock fails.
21
22 (+) Once the IWDG is started, the LSI is forced ON and both cannot 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 into the counter and the watchdog reset
29 is 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 the CPU 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 clock frequency dispersion.
43 STM32L5xx devices provide the capability to measure the LSI clock
44 frequency (LSI clock is internally connected to TIM16 CH1 input capture).
45 The measured value can be used to have an IWDG timeout with an
46 acceptable accuracy.
47
48 [..] Default timeout value (necessary for IWDG_SR status register update):
49 Constant LSI_VALUE is defined based on the nominal LSI clock frequency.
50 This frequency being subject to variations as mentioned above, the
51 default timeout value (defined through constant HAL_IWDG_DEFAULT_TIMEOUT
52 below) may become too short or too long.
53 In such cases, this default timeout value can be tuned by redefining
54 the constant LSI_VALUE at user-application level (based, for instance,
55 on the measured LSI clock frequency as explained above).
56
57 ##### How to use this driver #####
58 ==============================================================================
59 [..]
60 (#) Use IWDG using HAL_IWDG_Init() function to :
61 (++) Enable instance by writing Start keyword in IWDG_KEY register. LSI
62 clock is forced ON and IWDG counter starts counting down.
63 (++) Enable write access to configuration registers:
64 IWDG_PR, IWDG_RLR and IWDG_WINR.
65 (++) Configure the IWDG prescaler and counter reload value. This reload
66 value will be loaded in the IWDG counter each time the watchdog is
67 reloaded, then the IWDG will start counting down from this value.
68 (++) Depending on window parameter:
69 (+++) If Window Init parameter is same as Window register value,
70 nothing more is done but reload counter value in order to exit
71 function with exact time base.
72 (+++) Else modify Window register. This will automatically reload
73 watchdog counter.
74 (++) Wait for status flags to be reset.
75
76 (#) Then the application program must refresh the IWDG counter at regular
77 intervals during normal operation to prevent an MCU reset, using
78 HAL_IWDG_Refresh() function.
79
80 *** IWDG HAL driver macros list ***
81 ====================================
82 [..]
83 Below the list of most used macros in IWDG HAL driver:
84 (+) __HAL_IWDG_START: Enable the IWDG peripheral
85 (+) __HAL_IWDG_RELOAD_COUNTER: Reloads IWDG counter with value defined in
86 the reload register
87
88 @endverbatim
89 ******************************************************************************
90 * @attention
91 *
92 * <h2><center>© Copyright (c) 2019 STMicroelectronics.
93 * All rights reserved.</center></h2>
94 *
95 * This software component is licensed by ST under BSD 3-Clause license,
96 * the "License"; You may not use this file except in compliance with the
97 * License. You may obtain a copy of the License at:
98 * opensource.org/licenses/BSD-3-Clause
99 *
100 ******************************************************************************
101 */
102
103 /* Includes ------------------------------------------------------------------*/
104 #include "stm32l5xx_hal.h"
105
106 /** @addtogroup STM32L5xx_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 also 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 #define HAL_IWDG_DEFAULT_TIMEOUT ((6UL * 256UL * 1000UL) / LSI_VALUE)
129 #define IWDG_KERNEL_UPDATE_FLAGS (IWDG_SR_WVU | IWDG_SR_RVU | IWDG_SR_PVU)
130 /**
131 * @}
132 */
133
134 /* Private macro -------------------------------------------------------------*/
135 /* Private variables ---------------------------------------------------------*/
136 /* Private function prototypes -----------------------------------------------*/
137 /* Exported functions --------------------------------------------------------*/
138
139 /** @addtogroup IWDG_Exported_Functions
140 * @{
141 */
142
143 /** @addtogroup IWDG_Exported_Functions_Group1
144 * @brief Initialization and Start functions.
145 *
146 @verbatim
147 ===============================================================================
148 ##### Initialization and Start functions #####
149 ===============================================================================
150 [..] This section provides functions allowing to:
151 (+) Initialize the IWDG according to the specified parameters in the
152 IWDG_InitTypeDef of associated handle.
153 (+) Manage Window option.
154 (+) Once initialization is performed in HAL_IWDG_Init function, Watchdog
155 is reloaded in order to exit function with correct time base.
156
157 @endverbatim
158 * @{
159 */
160
161 /**
162 * @brief Initialize the IWDG according to the specified parameters in the
163 * IWDG_InitTypeDef and start watchdog. Before exiting function,
164 * watchdog is refreshed in order to have correct time base.
165 * @param hiwdg pointer to a IWDG_HandleTypeDef structure that contains
166 * the configuration information for the specified IWDG module.
167 * @retval HAL status
168 */
HAL_IWDG_Init(IWDG_HandleTypeDef * hiwdg)169 HAL_StatusTypeDef HAL_IWDG_Init(IWDG_HandleTypeDef *hiwdg)
170 {
171 uint32_t tickstart;
172
173 /* Check the IWDG handle allocation */
174 if (hiwdg == NULL)
175 {
176 return HAL_ERROR;
177 }
178
179 /* Check the parameters */
180 assert_param(IS_IWDG_ALL_INSTANCE(hiwdg->Instance));
181 assert_param(IS_IWDG_PRESCALER(hiwdg->Init.Prescaler));
182 assert_param(IS_IWDG_RELOAD(hiwdg->Init.Reload));
183 assert_param(IS_IWDG_WINDOW(hiwdg->Init.Window));
184
185 /* Enable IWDG. LSI is turned on automatically */
186 __HAL_IWDG_START(hiwdg);
187
188 /* Enable write access to IWDG_PR, IWDG_RLR and IWDG_WINR registers by writing
189 0x5555 in KR */
190 IWDG_ENABLE_WRITE_ACCESS(hiwdg);
191
192 /* Write to IWDG registers the Prescaler & Reload values to work with */
193 hiwdg->Instance->PR = hiwdg->Init.Prescaler;
194 hiwdg->Instance->RLR = hiwdg->Init.Reload;
195
196 /* Check pending flag, if previous update not done, return timeout */
197 tickstart = HAL_GetTick();
198
199 /* Wait for register to be updated */
200 while ((hiwdg->Instance->SR & IWDG_KERNEL_UPDATE_FLAGS) != 0x00u)
201 {
202 if ((HAL_GetTick() - tickstart) > HAL_IWDG_DEFAULT_TIMEOUT)
203 {
204 if ((hiwdg->Instance->SR & IWDG_KERNEL_UPDATE_FLAGS) != 0x00u)
205 {
206 return HAL_TIMEOUT;
207 }
208 }
209 }
210
211 /* If window parameter is different than current value, modify window
212 register */
213 if (hiwdg->Instance->WINR != hiwdg->Init.Window)
214 {
215 /* Write to IWDG WINR the IWDG_Window value to compare with. In any case,
216 even if window feature is disabled, Watchdog will be reloaded by writing
217 windows register */
218 hiwdg->Instance->WINR = hiwdg->Init.Window;
219 }
220 else
221 {
222 /* Reload IWDG counter with value defined in the reload register */
223 __HAL_IWDG_RELOAD_COUNTER(hiwdg);
224 }
225
226 /* Return function status */
227 return HAL_OK;
228 }
229
230
231 /**
232 * @}
233 */
234
235
236 /** @addtogroup IWDG_Exported_Functions_Group2
237 * @brief IO operation functions
238 *
239 @verbatim
240 ===============================================================================
241 ##### IO operation functions #####
242 ===============================================================================
243 [..] This section provides functions allowing to:
244 (+) Refresh the IWDG.
245
246 @endverbatim
247 * @{
248 */
249
250 /**
251 * @brief Refresh the IWDG.
252 * @param hiwdg pointer to a IWDG_HandleTypeDef structure that contains
253 * the configuration information for the specified IWDG module.
254 * @retval HAL status
255 */
HAL_IWDG_Refresh(IWDG_HandleTypeDef * hiwdg)256 HAL_StatusTypeDef HAL_IWDG_Refresh(IWDG_HandleTypeDef *hiwdg)
257 {
258 /* Reload IWDG counter with value defined in the reload register */
259 __HAL_IWDG_RELOAD_COUNTER(hiwdg);
260
261 /* Return function status */
262 return HAL_OK;
263 }
264
265
266 /**
267 * @}
268 */
269
270 /**
271 * @}
272 */
273
274 #endif /* HAL_IWDG_MODULE_ENABLED */
275 /**
276 * @}
277 */
278
279 /**
280 * @}
281 */
282
283 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
284
