STM32L053 USB with SYSCLK HSI16DIV

[antonello]

Posted on March 25, 2015 at 09:15

Greetings,

I'm developing an application using STM32L053 micro. I use usb device (composite hid, msc). When I  configure the system clock with HSI16, NO PLL  all DIVS to 1 everything works fine. Now I need to change this to run with HSI16DIV. (I simply change the HSI16DIVEN bit). Now the pc does not recognize the usb device any more.I do not see why since my understanding was that HSI48 clock feeding usb shold be independent;I post here the two configurations, the difference is in red:This works: 

RCC_OscInitTypeDef RCC_OscInitStruct;

   RCC_ClkInitTypeDef RCC_ClkInitStruct;

   RCC_PeriphCLKInitTypeDef PeriphClkInit;

   __PWR_CLK_ENABLE();

   __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);

   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI

      |RCC_OSCILLATORTYPE_LSE|RCC_OSCILLATORTYPE_HSI48;

   RCC_OscInitStruct.LSEState = RCC_LSE_ON;

   RCC_OscInitStruct.HSIState = RCC_HSI_ON;

   RCC_OscInitStruct.HSICalibrationValue = 16;

   RCC_OscInitStruct.LSIState = RCC_LSI_OFF;

   RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;

   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;

   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;

   RCC_OscInitStruct.PLL.PLLMUL = RCC_PLLMUL_3;

   RCC_OscInitStruct.PLL.PLLDIV = RCC_PLLDIV_2;

   HAL_RCC_OscConfig(&RCC_OscInitStruct);

   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;//RCC_SYSCLKSOURCE_PLLCLK;//RCC_SYSCLKSOURCE_PLLCLK;

   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_1);

   PeriphClkInit.PeriphClockSelection = /*RCC_PERIPHCLK_LPUART1|RCC_PERIPHCLK_I2C1

      |*/RCC_PERIPHCLK_RTC|RCC_PERIPHCLK_USB;

   PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK1;

   PeriphClkInit.I2c1ClockSelection = RCC_I2C1CLKSOURCE_PCLK1;

   PeriphClkInit.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;

   PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_HSI48;

   HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);

This does not:

RCC_OscInitTypeDef RCC_OscInitStruct;

   RCC_ClkInitTypeDef RCC_ClkInitStruct;

   RCC_PeriphCLKInitTypeDef PeriphClkInit;

   __PWR_CLK_ENABLE();

   __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);

   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI

      |RCC_OSCILLATORTYPE_LSE|RCC_OSCILLATORTYPE_HSI48;

   RCC_OscInitStruct.LSEState = RCC_LSE_ON;

   RCC_OscInitStruct.HSIState =

RCC_HSI_DIV4

;

   RCC_OscInitStruct.HSICalibrationValue = 16;

   RCC_OscInitStruct.LSIState = RCC_LSI_OFF;

   RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;

   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;

   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;

   RCC_OscInitStruct.PLL.PLLMUL = RCC_PLLMUL_3;

   RCC_OscInitStruct.PLL.PLLDIV = RCC_PLLDIV_2;

   HAL_RCC_OscConfig(&RCC_OscInitStruct);

   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;//RCC_SYSCLKSOURCE_PLLCLK;//RCC_SYSCLKSOURCE_PLLCLK;

   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_1);

   PeriphClkInit.PeriphClockSelection = /*RCC_PERIPHCLK_LPUART1|RCC_PERIPHCLK_I2C1

      |*/RCC_PERIPHCLK_RTC|RCC_PERIPHCLK_USB;

   PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK1;

   PeriphClkInit.I2c1ClockSelection = RCC_I2C1CLKSOURCE_PCLK1;

   PeriphClkInit.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;

   PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_HSI48;

   HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);

   #stm32-stm32l0-usb-clock-hsi16div