NUCLEO_F756ZG: Use HSE Bypass as PLL clock source

Author: ABOSTM

variants/NUCLEO_F756ZG/variant.cpp

@@ -151,14 +151,14 @@ extern "C" {
 /**
   * @brief  System Clock Configuration
   *         The system Clock is configured as follow :
-  *            System Clock source            = PLL (HSI)
+  *            System Clock source            = PLL (HSE)
   *            SYSCLK(Hz)                     = 216000000
   *            HCLK(Hz)                       = 216000000
   *            AHB Prescaler                  = 1
   *            APB1 Prescaler                 = 4
   *            APB2 Prescaler                 = 2
   *            HSE Frequency(Hz)              = 16000000
-  *            PLL_M                          = 8
+  *            PLL_M                          = 4
   *            PLL_N                          = 216
   *            PLL_P                          = 2
   *            PLL_Q                          = 9
@@ -182,12 +182,11 @@ WEAK void SystemClock_Config(void)
   __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
   /** Initializes the CPU, AHB and APB busses clocks
   */
-  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
-  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
-  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
+  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
+  RCC_OscInitStruct.HSEState = RCC_HSE_ON;  //RCC_HSE_BYPASS;
   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
-  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
-  RCC_OscInitStruct.PLL.PLLM = 8;
+  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
+  RCC_OscInitStruct.PLL.PLLM = 4;
   RCC_OscInitStruct.PLL.PLLN = 216;
   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
   RCC_OscInitStruct.PLL.PLLQ = 9;

variants/NUCLEO_F756ZG/variant.h

@@ -23,6 +23,8 @@
 extern "C" {
 #endif // __cplusplus
 
+#define HSE_VALUE    ((uint32_t)8000000U) /*!< Value of the External oscillator in Hz */
+
 /*----------------------------------------------------------------------------
  *        Pins
  *----------------------------------------------------------------------------*/