SystemClock Settings for STM32L0 mcu

[Pilous Droip]

Hi

I have my own board, with STM32L053C8T6TR. And I set clock and program failed here: while (LL_RCC_HSE_IsReady ()! = 1) {};

void SystemClock_Config(void) {
 
    LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_PWR); // clock pro PWR controller
    LL_PWR_SetRegulVoltageScaling(LL_PWR_REGU_VOLTAGE_SCALE1); // 1.8V pro core
    while (LL_PWR_IsActiveFlag_VOS())
           ; // wait on supply change
 
 
    // PLLCLK = 8MHz * 12 / 2 = 32MHz
    LL_RCC_HSE_EnableBypass();
    LL_RCC_HSE_Enable();
    while(LL_RCC_HSE_IsReady() != 1){};
    LL_FLASH_SetLatency(LL_FLASH_LATENCY_1);
    LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSE, LL_RCC_PLL_MUL_12, LL_RCC_PLL_DIV_3);
 
    LL_RCC_PLL_Enable();
    while(LL_RCC_PLL_IsReady() != 1){};
 
    /* Sysclk activation on the main PLL */
    LL_RCC_SetAHBPrescaler(LL_RCC_SYSCLK_DIV_1);
    LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);
    while(LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL){};
 
    /* Set APB1 & APB2 prescaler */
    LL_RCC_SetAPB1Prescaler(LL_RCC_APB1_DIV_1);
    LL_RCC_SetAPB2Prescaler(LL_RCC_APB2_DIV_1);
 
    SysTick_Config(32000000 / 1000);
 
    SystemCoreClock = 32000000;
 
    NVIC_SetPriorityGrouping(0x300);
 
    LL_Init1msTick(32000000);
    LL_SetSystemCoreClock(32000000);
 
    // Enable USB clock
    LL_RCC_SetUSBClockSource(LL_RCC_USB_CLKSOURCE_PLL);
 
    // Start timer TIM2
    CLOCK__StartMasterMSECtimer();
}

Does anyone see a problem here?

[TDK]

> I have my own board, with STM32L053C8T6TR

> LL_RCC_HSE_EnableBypass();

Do you have a clock signal coming in to HSE or are you using a crystal?

[Pilous Droip]

I use a crystal. This will probably be my problem. To be sure, I'll try to check it with an oscilloscope, but I have it at work.

So I'll try to rewrite my code and remove this line.

> LL_RCC_HSE_EnableBypass();

[TDK]

If you have a crystal, bypass mode is not what you want.

[Pilous Droip]

Yes. It is true. I have my own board, but I'm testing the application on NUCLEO-L053. And I forgot about this. Here is function clock settings for nucleo or my own board.

Thank you for your advice. :smiling_face_with_smiling_eyes:

void SystemClock_Config(void) {
#ifdef  NUCLEO-L053R8
    LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_PWR); // clock pro PWR controller
    LL_PWR_SetRegulVoltageScaling(LL_PWR_REGU_VOLTAGE_SCALE1); // 1.8V pro core
    while (LL_PWR_IsActiveFlag_VOS())
           ; // wait on change
    // PLLCLK = 8MHz * 12 / 2 = 32MHz
    LL_RCC_HSE_EnableBypass();
    LL_RCC_HSE_Enable();
    while(LL_RCC_HSE_IsReady() != 1){};
    LL_FLASH_SetLatency(LL_FLASH_LATENCY_1);
    LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSE, LL_RCC_PLL_MUL_12, LL_RCC_PLL_DIV_3);
 
    LL_RCC_PLL_Enable();
    while(LL_RCC_PLL_IsReady() != 1){};
 
    /* Sysclk activation on the main PLL */
    LL_RCC_SetAHBPrescaler(LL_RCC_SYSCLK_DIV_1);
    LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);
    while(LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL){};
 
    /* Set APB1 & APB2 prescaler */
    LL_RCC_SetAPB1Prescaler(LL_RCC_APB1_DIV_1);
    LL_RCC_SetAPB2Prescaler(LL_RCC_APB2_DIV_1);
 
    SysTick_Config(32000000 / 1000);
 
    SystemCoreClock = 32000000;
 
    NVIC_SetPriorityGrouping(0x300);
 
    LL_Init1msTick(32000000);
    LL_SetSystemCoreClock(32000000);
 
    LL_RCC_SetUSBClockSource(LL_RCC_USB_CLKSOURCE_PLL);
#else
    LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_PWR); // clock pro PWR kontrolér
    LL_FLASH_SetLatency(LL_FLASH_LATENCY_1);
    while (LL_FLASH_GetLatency() != LL_FLASH_LATENCY_1) {
    }
    LL_PWR_SetRegulVoltageScaling(LL_PWR_REGU_VOLTAGE_SCALE1);
    LL_RCC_HSE_Enable();
 
    /* Wait till HSE is ready */
    while (LL_RCC_HSE_IsReady() != 1) {
 
    }
    LL_RCC_LSI_Enable();
 
    /* Wait till LSI is ready */
    while (LL_RCC_LSI_IsReady() != 1) {
 
    }
    LL_PWR_EnableBkUpAccess();
    if (LL_RCC_GetRTCClockSource() != LL_RCC_RTC_CLKSOURCE_LSI) {
        LL_RCC_ForceBackupDomainReset();
        LL_RCC_ReleaseBackupDomainReset();
        LL_RCC_SetRTCClockSource(LL_RCC_RTC_CLKSOURCE_LSI);
    }
    LL_RCC_EnableRTC();
    LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSE, LL_RCC_PLL_MUL_12, LL_RCC_PLL_DIV_3);
    LL_RCC_PLL_Enable();
 
    /* Wait till PLL is ready */
    while (LL_RCC_PLL_IsReady() != 1) {
 
    }
    LL_RCC_SetAHBPrescaler(LL_RCC_SYSCLK_DIV_1);
    LL_RCC_SetAPB1Prescaler(LL_RCC_APB1_DIV_1);
    LL_RCC_SetAPB2Prescaler(LL_RCC_APB2_DIV_1);
    LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);
 
    /* Wait till System clock is ready */
    while (LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL) {
 
    }
    SysTick_Config(32000000 / 1000);
 
    SystemCoreClock = 32000000;
 
    NVIC_SetPriorityGrouping(0x300);
 
    LL_Init1msTick(32000000);
    LL_SetSystemCoreClock(32000000);
#endif
    CLOCK__StartMasterMSECtimer();
}