diff --git a/bsp/stm32/libraries/STM32WBxx_HAL/SConscript b/bsp/stm32/libraries/STM32WBxx_HAL/SConscript
index e4fe5d3259..75372b529e 100644
--- a/bsp/stm32/libraries/STM32WBxx_HAL/SConscript
+++ b/bsp/stm32/libraries/STM32WBxx_HAL/SConscript
@@ -24,6 +24,7 @@ STM32WBxx_HAL_Driver/Src/stm32wbxx_hal_rcc.c
 STM32WBxx_HAL_Driver/Src/stm32wbxx_hal_rcc_ex.c
 STM32WBxx_HAL_Driver/Src/stm32wbxx_hal_rng.c
 STM32WBxx_HAL_Driver/Src/stm32wbxx_hal_gpio.c
+STM32WBxx_HAL_Driver/Src/stm32wbxx_hal_hsem.c
 ''')
   
 if GetDepend(['RT_USING_SERIAL']):
diff --git a/bsp/stm32/stm32wb55-st-nucleo/board/board.c b/bsp/stm32/stm32wb55-st-nucleo/board/board.c
index 13796c442c..11c7c8cf2b 100644
--- a/bsp/stm32/stm32wb55-st-nucleo/board/board.c
+++ b/bsp/stm32/stm32wb55-st-nucleo/board/board.c
@@ -1,11 +1,12 @@
 /*
- * Copyright (c) 2006-2021, RT-Thread Development Team
+ * Copyright (c) 2006-2018, RT-Thread Development Team
  *
  * SPDX-License-Identifier: Apache-2.0
  *
  * Change Logs:
  * Date           Author       Notes
  * 2018-11-06     SummerGift   first version
+ * 2021-03-27     xph          open rtc clk to support ble stack
  */
 
 #include "board.h"
@@ -26,9 +27,7 @@ void SystemClock_Config(void)
   /** Initializes the RCC Oscillators according to the specified parameters
   * in the RCC_OscInitTypeDef structure.
   */
-  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_LSI1
-                              |RCC_OSCILLATORTYPE_HSE|RCC_OSCILLATORTYPE_LSE
-                              |RCC_OSCILLATORTYPE_MSI;
+  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI | RCC_OSCILLATORTYPE_LSI1 | RCC_OSCILLATORTYPE_HSE | RCC_OSCILLATORTYPE_LSE | RCC_OSCILLATORTYPE_MSI;
   RCC_OscInitStruct.HSEState = RCC_HSE_ON;
   RCC_OscInitStruct.LSEState = RCC_LSE_ON;
   RCC_OscInitStruct.HSIState = RCC_HSI_ON;
@@ -50,9 +49,7 @@ void SystemClock_Config(void)
   }
   /** Configure the SYSCLKSource, HCLK, PCLK1 and PCLK2 clocks dividers
   */
-  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK4|RCC_CLOCKTYPE_HCLK2
-                              |RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
-                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
+  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK4 | RCC_CLOCKTYPE_HCLK2 | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2;
   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
@@ -64,22 +61,12 @@ void SystemClock_Config(void)
   {
     Error_Handler();
   }
-  /** Initializes the peripherals clocks
-  */
-  PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_SMPS|RCC_PERIPHCLK_RTC
-                              |RCC_PERIPHCLK_USART1|RCC_PERIPHCLK_LPUART1
-                              |RCC_PERIPHCLK_USB|RCC_PERIPHCLK_ADC;
-  PeriphClkInitStruct.PLLSAI1.PLLN = 24;
-  PeriphClkInitStruct.PLLSAI1.PLLP = RCC_PLLP_DIV2;
-  PeriphClkInitStruct.PLLSAI1.PLLQ = RCC_PLLQ_DIV2;
-  PeriphClkInitStruct.PLLSAI1.PLLR = RCC_PLLR_DIV2;
-  PeriphClkInitStruct.PLLSAI1.PLLSAI1ClockOut = RCC_PLLSAI1_USBCLK|RCC_PLLSAI1_ADCCLK;
+  PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_SMPS | RCC_PERIPHCLK_RFWAKEUP | RCC_PERIPHCLK_RTC | RCC_PERIPHCLK_USART1 | RCC_PERIPHCLK_LPUART1;
   PeriphClkInitStruct.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;
   PeriphClkInitStruct.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK1;
-  PeriphClkInitStruct.UsbClockSelection = RCC_USBCLKSOURCE_PLLSAI1;
-  PeriphClkInitStruct.AdcClockSelection = RCC_ADCCLKSOURCE_PLLSAI1;
-  PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSI;
-  PeriphClkInitStruct.SmpsClockSelection = RCC_SMPSCLKSOURCE_HSI;
+  PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;
+  PeriphClkInitStruct.RFWakeUpClockSelection = RCC_RFWKPCLKSOURCE_LSE;
+  PeriphClkInitStruct.SmpsClockSelection = RCC_SMPSCLKSOURCE_HSE;
   PeriphClkInitStruct.SmpsDivSelection = RCC_SMPSCLKDIV_RANGE1;
   if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
   {