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12 | ============================================================================== |
12 | ============================================================================== |
13 | ##### RCC specific features ##### |
13 | ##### RCC specific features ##### |
14 | ============================================================================== |
14 | ============================================================================== |
15 | [..] |
15 | [..] |
16 | After reset the device is running from Internal High Speed oscillator |
16 | After reset the device is running from Internal High Speed oscillator |
17 | (HSI 8MHz) with Flash 0 wait state, Flash prefetch buffer is enabled, |
17 | (HSI 8MHz) with Flash 0 wait state, Flash prefetch buffer is disabled, |
18 | and all peripherals are off except internal SRAM, Flash and JTAG. |
18 | and all peripherals are off except internal SRAM, Flash and JTAG. |
19 | (+) There is no prescaler on High speed (AHB) and Low speed (APB) buses; |
19 | (+) There is no prescaler on High speed (AHB) and Low speed (APB) buses; |
20 | all peripherals mapped on these buses are running at HSI speed. |
20 | all peripherals mapped on these buses are running at HSI speed. |
21 | (+) The clock for all peripherals is switched off, except the SRAM and FLASH. |
21 | (+) The clock for all peripherals is switched off, except the SRAM and FLASH. |
22 | (+) All GPIOs are in input floating state, except the JTAG pins which |
22 | (+) All GPIOs are in input floating state, except the JTAG pins which |
Line 158... | Line 158... | ||
158 | The AHB clock (HCLK) is derived from System clock through configurable |
158 | The AHB clock (HCLK) is derived from System clock through configurable |
159 | prescaler and used to clock the CPU, memory and peripherals mapped |
159 | prescaler and used to clock the CPU, memory and peripherals mapped |
160 | on AHB bus (DMA, GPIO...). APB1 (PCLK1) clock is derived |
160 | on AHB bus (DMA, GPIO...). APB1 (PCLK1) clock is derived |
161 | from AHB clock through configurable prescalers and used to clock |
161 | from AHB clock through configurable prescalers and used to clock |
162 | the peripherals mapped on these buses. You can use |
162 | the peripherals mapped on these buses. You can use |
163 | "@ref HAL_RCC_GetSysClockFreq()" function to retrieve the frequencies of these clocks. |
163 | "HAL_RCC_GetSysClockFreq()" function to retrieve the frequencies of these clocks. |
164 | 164 | ||
165 | (#) All the peripheral clocks are derived from the System clock (SYSCLK) except: |
165 | (#) All the peripheral clocks are derived from the System clock (SYSCLK) except: |
166 | (++) The FLASH program/erase clock which is always HSI 8MHz clock. |
166 | (++) The FLASH program/erase clock which is always HSI 8MHz clock. |
167 | (++) The USB 48 MHz clock which is derived from the PLL VCO clock. |
167 | (++) The USB 48 MHz clock which is derived from the PLL VCO clock. |
168 | (++) The USART clock which can be derived as well from HSI 8MHz, LSI or LSE. |
168 | (++) The USART clock which can be derived as well from HSI 8MHz, LSI or LSE. |