HAL RCC Use Cases ¶

User application sets the system at maximum frequency ¶

$@startuml participant Application participant HAL participant HAL_RCC participant HAL_GPIO participant HAL_FLASH participant RCC_REG note over Application : Enable HSIS oscillator Application -> HAL_RCC : HAL_RCC_HSIS_Enable() HAL_RCC --> RCC_REG : enable HSIS oscillator HAL_RCC <-- RCC_REG alt timeout case (HSIS Ready flag not set) HAL_RCC --> Application : HAL_ERROR else HAL_RCC --> Application : HAL_OK note over Application: Increasing the number\nof wait states\nbecause of higher\nCPU frequency Application -> HAL_FLASH : HAL_FLASH_ITF_SetLatency\n(HAL_FLASH_ITF_LATENCY_4) note over Application : Set HSIS as source\nclock of system clock loop HSIS is selected as System Clock Source end Application -> HAL_RCC : HAL_RCC_SetSYSCLKSource\n(HAL_RCC_SYSCLK_SRC_HSIS) HAL_RCC --> RCC_REG : set system clock source note over HAL_RCC : update SystemCoreClock HAL_RCC -> HAL : HAL_InitTick HAL_RCC <-- HAL Application <-- HAL_RCC end @enduml$

Called functions:

HAL_RCC_SetSYSCLKSource()

Reset the RCC clock configuration to the default system clock (HSIDIV3: 48 MHz) ¶

$@startuml participant Application participant HAL participant HAL_RCC participant LL_RCC == HAL_RCC_ResetSystemClock function == Application -> HAL_RCC : HAL_RCC_ResetSystemClock note over HAL_RCC : Enable HSIDIV3 HAL_RCC -> LL_RCC : LL_RCC_HSIDIV3_Enable HAL_RCC <-- LL_RCC HAL_RCC -> LL_RCC : LL_RCC_HSIDIV3_IsReady alt timetout issue (HSIDIV3 not enabled) HAL_RCC --> Application : HAL_ERROR else HSIDIV3 enabled note over HAL_RCC : Select HSIDIV3\nas system clock source HAL_RCC -> LL_RCC : LL_RCC_SetSysClkSource\n(LL_RCC_SYS_CLKSOURCE_HSIDIV3) HAL_RCC <-- LL_RCC HAL_RCC -> LL_RCC : LL_RCC_GetSysClkSource alt timetout issue (HSIDIV3 not selected as clock source) HAL_RCC --> Application : HAL_ERROR else HSIDIV3 selected as clock source HAL_RCC -> LL_RCC : LL_RCC_SetAHBPrescaler\n(LL_RCC_HCLK_PRESCALER_1) note over HAL_RCC : Set SystemCoreClock\nto HSI_RESET_VALUE HAL_RCC -> HAL: HAL_InitTick HAL --> HAL_RCC: HAL_OK HAL_RCC --> Application: HAL_OK end end @enduml$

Called functions:

HAL_RCC_ResetSystemClock()

Enable HSE with unitary function example_1 ¶

Called functions:

HAL_RCC_HSE_Enable()

Enable HSE with unitary function example_2 ¶

Called functions:

HAL_RCC_HSE_Enable()
HAL_RCC_HSE_Disable()

Bus prescalers configuration ¶

$@startuml == Call the global HAL_RCC_SetBusClockConfig == alt Increasing the number of wait states because of higher CPU frequency Application -> HAL_FLASH : HAL_FLASH_ITF_GetLatency HAL_FLASH --> Application : // return Current_latency note over Application : if HAL_FLASH_ITF_LATENCY_X > Current_latency Application -> HAL_FLASH : HAL_FLASH_ITF_SetLatency\n(HAL_FLASH_ITF_LATENCY_X) Application <-- HAL_FLASH end note over Application : Fill hal_rcc_bus_clk_config_t structure\n(config_bus) alt Increasing the BUS frequency divider note over Application : if ({bus}_clk_divider > current_{bus}_clock) Application -> HAL_RCC : HAL_RCC_SetBusClockConfig\n(&config_bus) HAL_RCC -> RCC_REG : update {bus} dividers in RCC registers HAL_RCC <-- RCC_REG Application <-- HAL_RCC end loop HSIDIV3 is selected as System Clock Source end Application -> HAL_RCC : HAL_RCC_SetSYSCLKSource\n(HAL_RCC_SYSCLK_SRC_HSIS) HAL_RCC -> RCC_REG : set system clock source HAL_RCC <-- RCC_REG Application <-- HAL_RCC alt Decreasing the number of wait states because of lower CPU frequency Application -> HAL_FLASH : HAL_FLASH_ITF_GetLatency HAL_FLASH --> Application : // return Current_latency note over Application : if HAL_FLASH_ITF_LATENCY_X < Current_latency Application -> HAL_FLASH : HAL_FLASH_ITF_SetLatency\n(HAL_FLASH_ITF_LATENCY_X) Application <-- HAL_FLASH end alt Decreasing the BUS frequency divider note over Application : if ({bus}_clk_divider < current_{bus}_clock) Application -> HAL_RCC : HAL_RCC_SetBusClockConfig\n(&config_bus) HAL_RCC -> RCC_REG : update {bus} dividers in RCC registers HAL_RCC <-- RCC_REG Application <-- HAL_RCC end note over HAL_RCC : update SystemCoreClock HAL_RCC -> HAL : HAL_InitTick HAL --> HAL_RCC Application <-- HAL_RCC @enduml$

Called functions:

Usage of HAL_RCC_SetConfigMCO ¶

$@startuml participant Application participant HAL_RCC participant HAL_GPIO participant LL_RCC == GPIO initialization outside HAL_RCC_SetConfigMCO == note over Application : Initialize MCO pin on PA8\n hal_gpio_init_t init_struct;\n init_struct.Mode = HAL_GPIO_MODE_ALTERNATE;\n init_struct.Speed = HAL_GPIO_SPEED_FREQ_HIGH;\n init_struct.Pull = HAL_GPIO_PULL_NO;\n init_struct.Alternate = HAL_GPIO_AF0_MCO; Application -> HAL_RCC : HAL_RCC_GPIOA_EnableClock HAL_RCC -> LL_RCC : LL_AHB2_GRP1_EnableClock\n(LL_AHB2_GRP1_PERIPH_GPIOA) HAL_RCC <-- LL_RCC Application <-- HAL_RCC Application -> HAL_GPIO : HAL_GPIO_Init(HAL_GPIOA, &init_struct, HAL_GPIO_PIN_8) Application <-- HAL_GPIO Application -> HAL_RCC : HAL_RCC_SetConfigMCO HAL_RCC -> LL_RCC : LL_RCC_ConfigMCO HAL_RCC <-- LL_RCC Application <-- HAL_RCC @enduml$

Called functions:

Usage of HAL_RCC_EnableLSCO ¶

$@startuml participant Application participant HAL_RCC participant HAL_PWR participant HAL_GPIO participant LL_RCC == GPIO initialization outside HAL_RCC_EnableLSCO == note over Application : Initialize LSCO pin on PA2\n hal_gpio_init_t init_struct;\n init_struct.mode = HAL_GPIO_MODE_ANALOG;\n init_struct.speed = HAL_GPIO_SPEED_FREQ_HIGH;\n init_struct.pull = HAL_GPIO_PULL_NO; Application -> HAL_RCC : HAL_RCC_GPIOA_EnableClock HAL_RCC --> Application Application -> HAL_GPIO : HAL_GPIO_Init(HAL_GPIOA, &init_struct, HAL_GPIO_PIN_2) HAL_GPIO --> Application alt Write Protection domain is enabled Application -> HAL_PWR : HAL_PWR_DisableRTCDomainWriteProtection() HAL_PWR --> Application end Application -> HAL_RCC : HAL_RCC_EnableLSCO HAL_RCC -> LL_RCC : LL_RCC_ConfigLSCO HAL_RCC -> LL_RCC : LL_RCC_LSCO_Enable HAL_RCC <-- LL_RCC HAL_RCC --> Application : HAL_OK @enduml$

Called functions: