/**
* @brief System Clock Configuration
* The system Clock is configured as follow:
* HSI48 used as USB clock source
* - System Clock source = HSI
* - HSI Frequency(Hz) = 16000000
* - SYSCLK(Hz) = 16000000
* - HCLK(Hz) = 16000000
* - AHB Prescaler = 1
* - APB1 Prescaler = 1
* - APB2 Prescaler = 1
* - Flash Latency(WS) = 0
* - Main regulator output voltage = Scale1 mode
* @param None
* @retval None
*/
static void SystemClock_Config(void)
{
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
static RCC_CRSInitTypeDef RCC_CRSInitStruct;
/* Enable HSI Oscillator to be used as System clock source
Enable HSI48 Oscillator to be used as USB clock source */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI | RCC_OSCILLATORTYPE_HSI48;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;
HAL_RCC_OscConfig(&RCC_OscInitStruct);
/* Select HSI48 as USB clock source */
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_USB;
PeriphClkInitStruct.UsbClockSelection = RCC_USBCLKSOURCE_HSI48;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
/* Select HSI as system clock source and configure the HCLK, PCLK1 and PCLK2
clock dividers */
RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0);
/* Configure the clock recovery system (CRS) ********************************/
/* Enable CRS Clock */
__CRS_CLK_ENABLE();
/* Default Synchro Signal division factor (not divided) */
RCC_CRSInitStruct.Prescaler = RCC_CRS_SYNC_DIV1;
/* Set the SYNCSRC[1:0] bits according to CRS_Source value */
RCC_CRSInitStruct.Source = RCC_CRS_SYNC_SOURCE_USB;
/* HSI48 is synchronized with USB SOF at 1KHz rate */
RCC_CRSInitStruct.ReloadValue = __HAL_RCC_CRS_CALCULATE_RELOADVALUE(48000000, 1000);
RCC_CRSInitStruct.ErrorLimitValue = RCC_CRS_ERRORLIMIT_DEFAULT;
/* Set the TRIM[5:0] to the default value */
RCC_CRSInitStruct.HSI48CalibrationValue = 0x20;
/* Start automatic synchronization */
HAL_RCCEx_CRSConfig (&RCC_CRSInitStruct);
/* Enable Power Controller clock */
__PWR_CLK_ENABLE();
/* The voltage scaling allows optimizing the power consumption when the device is
clocked below the maximum system frequency, to update the voltage scaling value
regarding system frequency refer to product datasheet. */
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
}
static void SystemClock_Config(void)
{
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
static RCC_CRSInitTypeDef RCC_CRSInitStruct;
/* Enable HSI48 Oscillator to be used as system clock source */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI48;
HAL_RCC_OscConfig(&RCC_OscInitStruct);
/* Select HSI48 as USB clock source */
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_USB;
PeriphClkInitStruct.UsbClockSelection = RCC_USBCLKSOURCE_HSI48;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
/* Select HSI48 as system clock source and configure the HCLK and PCLK1 clock dividers */
RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1);
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI48;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1);
/*Configure the clock recovery system (CRS)**********************************/
/*Enable CRS Clock*/
__CRS_CLK_ENABLE();
/* Default Synchro Signal division factor (not divided) */
RCC_CRSInitStruct.Prescaler = RCC_CRS_SYNC_DIV1;
/* Set the SYNCSRC[1:0] bits according to CRS_Source value */
RCC_CRSInitStruct.Source = RCC_CRS_SYNC_SOURCE_USB;
/* HSI48 is synchronized with USB SOF at 1KHz rate */
RCC_CRSInitStruct.ReloadValue = __HAL_RCC_CRS_CALCULATE_RELOADVALUE(48000000, 1000);
RCC_CRSInitStruct.ErrorLimitValue = RCC_CRS_ERRORLIMIT_DEFAULT;
/* Set the TRIM[5:0] to the default value*/
RCC_CRSInitStruct.HSI48CalibrationValue = 0x20;
/* Start automatic synchronization */
HAL_RCCEx_CRSConfig (&RCC_CRSInitStruct);
}
/**
* @brief Main program
* @param None
* @retval None
*/
int main(void)
{
/* STM32F0xx HAL library initialization:
- Configure the Flash prefetch
- Systick timer is configured by default as source of time base, but user
can eventually implement his proper time base source (a general purpose
timer for example or other time source), keeping in mind that Time base
duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and
handled in milliseconds basis.
- Low Level Initialization
*/
uint32_t status = RCC_CRS_TIMEOUT;
RCC_CRSSynchroInfoTypeDef syncinfo = {0};
RCC_CRSInitTypeDef crsinitstruct = {0};
HAL_Init();
/* Configure LED1 and LED3 */
BSP_LED_Init(LED1);
BSP_LED_Init(LED3);
/* Enable HSE oscillator and configure the PLL to reach the max system frequency (48 MHz)
when using HSE oscillator as PLL clock source. */
SystemClock_Config();
/* CRS initialization (enable HSI48 and LSE oscillators and then enable CRS clock */
CRS_Init();
/* HSI48 Synchronization with LSE frequency */
crsinitstruct.Prescaler = RCC_CRS_SYNC_DIV1;
crsinitstruct.Source = RCC_CRS_SYNC_SOURCE_LSE;
crsinitstruct.Polarity = RCC_CRS_SYNC_POLARITY_FALLING;
/* F(LSE)=32.768kHz then Reload=(f(Target)/f(LSE))-1= 0x5B7*/
crsinitstruct.ReloadValue = __HAL_RCC_CRS_CALCULATE_RELOADVALUE(48000000,32768);
crsinitstruct.ErrorLimitValue = RCC_CRS_ERRORLIMIT_DEFAULT;
/* Change the HSI trimming value to see the automatic calibration performed by CRS */
crsinitstruct.HSI48CalibrationValue = 0x00;
/* Start automatic synchronization using polling mode */
HAL_RCCEx_CRSConfig(&crsinitstruct);
/* Wait for synchronization OK event */
do
{
/* Check status of CRS synchronization */
/* Timeout is based on F(LSE) then less than 1 ms*/
status = HAL_RCCEx_CRSWaitSynchronization(1);
if ((status & RCC_CRS_TIMEOUT) == RCC_CRS_TIMEOUT)
{
/* Timeout issue. May have a problem with synchronization frequency */
Error_Handler();
}
/* Adapt synchronization input parameters in case of SYNC error or SYNC miss event */
if (((status & RCC_CRS_SYNCERR) == RCC_CRS_SYNCERR) || ((status & RCC_CRS_SYNCMISS) == RCC_CRS_SYNCMISS))
{
HAL_RCCEx_CRSGetSynchronizationInfo(&syncinfo);
/* User can check different parameters returned in synchronization info structure*/
/* and restart a new synchronization in changing input parameters */
HAL_RCCEx_CRSConfig(&crsinitstruct);
}
}
while((status & RCC_CRS_SYNCOK) != RCC_CRS_SYNCOK);
/* Power on LED1 */
BSP_LED_On(LED1);
/* Infinite loop */
while (1)
{
}
}
/**
* @brief Main program
* @param None
* @retval None
*/
int main(void)
{
/* STM32F0xx HAL library initialization:
- Configure the Flash prefetch
- Systick timer is configured by default as source of time base, but user
can eventually implement his proper time base source (a general purpose
timer for example or other time source), keeping in mind that Time base
duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and
handled in milliseconds basis.
- Low Level Initialization
*/
RCC_CRSSynchroInfoTypeDef syncinfo = {0};
HAL_Init();
/* Configure LED1, LED2, LED4 and LED3 */
BSP_LED_Init(LED1);
BSP_LED_Init(LED2);
BSP_LED_Init(LED4);
BSP_LED_Init(LED3);
/* Enable HSE oscillator and configure the PLL to reach the max system frequency (48 MHz)
when using HSE oscillator as PLL clock source. */
SystemClock_Config();
/* CRS initialization (enable HSI48 and LSE oscillators and then enable CRS clock */
/* Enable RCC_CRS interuption*/
CRS_Init();
/* HSI48 Synchronization without synchronization frequency (source set to GPIO */
/* which is not configured)*/
CRSInitStruct.Prescaler = RCC_CRS_SYNC_DIV1;
CRSInitStruct.Source = RCC_CRS_SYNC_SOURCE_GPIO;
CRSInitStruct.Polarity = RCC_CRS_SYNC_POLARITY_FALLING;
/* F(LSE)=32.768kHz then Reload=(f(Target)/f(LSE))-1= 0x5B7*/
CRSInitStruct.ReloadValue = __HAL_RCC_CRS_CALCULATE_RELOADVALUE(48000000,32768);
CRSInitStruct.ErrorLimitValue = RCC_CRS_ERRORLIMIT_DEFAULT;
/* Change the HSI trimming value to see the automatic calibration performed by CRS */
CRSInitStruct.HSI48CalibrationValue = 0x00;
/* Start automatic synchronization*/
HAL_RCCEx_CRSConfig(&CRSInitStruct);
/* Enable RCC_CRS Interuptions */
__HAL_RCC_CRS_ENABLE_IT(RCC_CRS_IT_SYNCOK | RCC_CRS_IT_SYNCWARN | RCC_CRS_IT_ERR | RCC_CRS_IT_ESYNC);
/* Simulate a SYNC EVENT which will raise a SYNC_MISS EVENT */
HAL_RCCEx_CRSSoftwareSynchronizationGenerate();
/* Infinite loop */
while (1)
{
/* Perform a new configuration to LSE when SYNC MISS is detected. */
if (CRSSyncStatus == 2)
{
/* Delay to see the LED power on switch from LED4 to LED1 */
HAL_Delay(1000);
/* Retrieve synchronization information if needed */
HAL_RCCEx_CRSGetSynchronizationInfo(&syncinfo);
/* Change source to LSE and restart synchronization */
CRSInitStruct.Source = RCC_CRS_SYNC_SOURCE_LSE;
HAL_RCCEx_CRSConfig(&CRSInitStruct);
/* Enable RCC_CRS Interuptions */
__HAL_RCC_CRS_ENABLE_IT(RCC_CRS_IT_SYNCOK | RCC_CRS_IT_SYNCWARN | RCC_CRS_IT_ERR | RCC_CRS_IT_ESYNC);
}
}
}
/**
* @brief System Clock Configuration
* The system Clock is configured as follow:
*
* HSI48 used as clock source (USE_CLKSOURCE_CRSHSI48 defined in main.h)
* - System Clock source = HSI48
* - SYSCLK(Hz) = 48000000
* - HCLK(Hz) = 48000000
* - AHB Prescaler = 1
* - APB1 Prescaler = 1
* - Flash Latency(WS) = 1
*
* - PLL(HSE) used as clock source (USE_CLKSOURCE_PLL defined in main.h)
* - System Clock source = PLL (HSE)
* - SYSCLK(Hz) = 48000000
* - HCLK(Hz) = 48000000
* - AHB Prescaler = 1
* - APB1 Prescaler = 1
* - HSE Frequency(Hz) = 8000000
* - PREDIV = 1
* - PLLMUL = 6
* - Flash Latency(WS) = 1
*
* @param None
* @retval None
*/
static void SystemClock_Config(void)
{
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_OscInitTypeDef RCC_OscInitStruct;
#if defined (USE_CLKSOURCE_CRSHSI48)
static RCC_CRSInitTypeDef RCC_CRSInitStruct;
#endif
#if defined (USE_CLKSOURCE_CRSHSI48)
/* Enable HSI48 Oscillator to be used as system clock source */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI48;
HAL_RCC_OscConfig(&RCC_OscInitStruct);
/* Select HSI48 as system clock source and configure the HCLK and PCLK1
clock dividers */
RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1);
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI48;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1);
/*Configure the clock recovery system (CRS)**********************************/
/*Enable CRS Clock*/
__CRS_CLK_ENABLE();
/* Default Synchro Signal division factor (not divided) */
RCC_CRSInitStruct.Prescaler = RCC_CRS_SYNC_DIV1;
/* Set the SYNCSRC[1:0] bits according to CRS_Source value */
RCC_CRSInitStruct.Source = RCC_CRS_SYNC_SOURCE_USB;
/* HSI48 is synchronized with USB SOF at 1KHz rate */
RCC_CRSInitStruct.ReloadValue = __HAL_RCC_CRS_CALCULATE_RELOADVALUE(48000000, 1000);
RCC_CRSInitStruct.ErrorLimitValue = RCC_CRS_ERRORLIMIT_DEFAULT;
/* Set the TRIM[5:0] to the default value*/
RCC_CRSInitStruct.HSI48CalibrationValue = 0x20;
/* Start automatic synchronization */
HAL_RCCEx_CRSConfig (&RCC_CRSInitStruct);
#elif defined (USE_CLKSOURCE_PLL)
/* Enable HSE Oscillator and activate PLL with HSE as source
PLLCLK = (8 * 6) / 1) = 48 MHz */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL6;
RCC_OscInitStruct.PLL.PREDIV = RCC_PREDIV_DIV1;
HAL_RCC_OscConfig(&RCC_OscInitStruct);
/* Select PLL as system clock source and configure the HCLK and PCLK1
clock dividers */
RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1);
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1);
#endif /*USE_CLKSOURCE_CRSHSI48*/
}
