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| 16 | * |
16 | * |
| 17 | * - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must |
17 | * - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must |
| 18 | * be called whenever the core clock is changed |
18 | * be called whenever the core clock is changed |
| 19 | * during program execution. |
19 | * during program execution. |
| 20 | * |
20 | * |
| 21 | * 2. After each device reset the HSI (8 MHz) is used as system clock source. |
- | |
| 22 | * Then SystemInit() function is called, in "startup_stm32f0xx.s" file, to |
- | |
| 23 | * configure the system clock before to branch to main program. |
- | |
| 24 | * |
21 | * |
| 25 | * 3. This file configures the system clock as follows: |
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| 26 | *============================================================================= |
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| 27 | * Supported STM32F0xx device |
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| 28 | *----------------------------------------------------------------------------- |
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| 29 | * System Clock source | HSI |
- | |
| 30 | *----------------------------------------------------------------------------- |
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| 31 | * SYSCLK(Hz) | 8000000 |
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| 32 | *----------------------------------------------------------------------------- |
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| 33 | * HCLK(Hz) | 8000000 |
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| 34 | *----------------------------------------------------------------------------- |
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| 35 | * AHB Prescaler | 1 |
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| 36 | *----------------------------------------------------------------------------- |
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| 37 | * APB1 Prescaler | 1 |
- | |
| 38 | *----------------------------------------------------------------------------- |
- | |
| 39 | *============================================================================= |
- | |
| 40 | ****************************************************************************** |
22 | ****************************************************************************** |
| 41 | * @attention |
23 | * @attention |
| 42 | * |
24 | * |
| 43 | * <h2><center>© Copyright (c) 2016 STMicroelectronics. |
25 | * <h2><center>© Copyright (c) 2016 STMicroelectronics. |
| 44 | * All rights reserved.</center></h2> |
26 | * All rights reserved.</center></h2> |
| Line 111... | Line 93... | ||
| 111 | */ |
93 | */ |
| 112 | /* This variable is updated in three ways: |
94 | /* This variable is updated in three ways: |
| 113 | 1) by calling CMSIS function SystemCoreClockUpdate() |
95 | 1) by calling CMSIS function SystemCoreClockUpdate() |
| 114 | 2) by calling HAL API function HAL_RCC_GetHCLKFreq() |
96 | 2) by calling HAL API function HAL_RCC_GetHCLKFreq() |
| 115 | 3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency |
97 | 3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency |
| 116 | Note: If you use this function to configure the system clock there is no need to |
98 | Note: If you use this function to configure the system clock; then there |
| 117 | call the 2 first functions listed above, since SystemCoreClock variable is |
99 | is no need to call the 2 first functions listed above, since SystemCoreClock |
| 118 | updated automatically. |
100 | variable is updated automatically. |
| 119 | */ |
101 | */ |
| 120 | uint32_t SystemCoreClock = 8000000; |
102 | uint32_t SystemCoreClock = 8000000; |
| 121 | 103 | ||
| 122 | const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9}; |
104 | const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9}; |
| 123 | const uint8_t APBPrescTable[8] = {0, 0, 0, 0, 1, 2, 3, 4}; |
105 | const uint8_t APBPrescTable[8] = {0, 0, 0, 0, 1, 2, 3, 4}; |
| Line 137... | Line 119... | ||
| 137 | /** @addtogroup STM32F0xx_System_Private_Functions |
119 | /** @addtogroup STM32F0xx_System_Private_Functions |
| 138 | * @{ |
120 | * @{ |
| 139 | */ |
121 | */ |
| 140 | 122 | ||
| 141 | /** |
123 | /** |
| 142 | * @brief Setup the microcontroller system. |
124 | * @brief Setup the microcontroller system |
| 143 | * @param None |
125 | * @param None |
| 144 | * @retval None |
126 | * @retval None |
| 145 | */ |
127 | */ |
| 146 | void SystemInit(void) |
128 | void SystemInit(void) |
| 147 | { |
129 | { |
| Line 172... | Line 154... | ||
| 172 | * - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**) |
154 | * - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**) |
| 173 | * |
155 | * |
| 174 | * - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**) |
156 | * - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**) |
| 175 | * or HSI_VALUE(*) multiplied/divided by the PLL factors. |
157 | * or HSI_VALUE(*) multiplied/divided by the PLL factors. |
| 176 | * |
158 | * |
| 177 | * (*) HSI_VALUE is a constant defined in stm32f0xx_hal.h file (default value |
159 | * (*) HSI_VALUE is a constant defined in stm32f0xx_hal_conf.h file (default value |
| 178 | * 8 MHz) but the real value may vary depending on the variations |
160 | * 8 MHz) but the real value may vary depending on the variations |
| 179 | * in voltage and temperature. |
161 | * in voltage and temperature. |
| 180 | * |
162 | * |
| 181 | * (**) HSE_VALUE is a constant defined in stm32f0xx_hal.h file (default value |
163 | * (**) HSE_VALUE is a constant defined in stm32f0xx_hal_conf.h file (its value |
| 182 | * 8 MHz), user has to ensure that HSE_VALUE is same as the real |
164 | * depends on the application requirements), user has to ensure that HSE_VALUE |
| 183 | * frequency of the crystal used. Otherwise, this function may |
165 | * is same as the real frequency of the crystal used. Otherwise, this function |
| 184 | * have wrong result. |
166 | * may have wrong result. |
| 185 | * |
167 | * |
| 186 | * - The result of this function could be not correct when using fractional |
168 | * - The result of this function could be not correct when using fractional |
| 187 | * value for HSE crystal. |
169 | * value for HSE crystal. |
| 188 | * |
170 | * |
| 189 | * @param None |
171 | * @param None |