chore: enhance Nucleo L432KC system clock config

Allows LPUART low baudrate (9600) which is common
in Arduino example.

Fixes #2897.

Signed-off-by: Frederic Pillon <frederic.pillon@st.com>

Author: fpistm

variants/STM32L4xx/L432K(B-C)U_L442KCU/variant_NUCLEO_L432KC.cpp

@@ -71,20 +71,34 @@ WEAK void SystemClock_Config(void)
   RCC_OscInitTypeDef RCC_OscInitStruct = {};
   RCC_PeriphCLKInitTypeDef PeriphClkInit = {};
 
-  /* MSI is enabled after System reset, activate PLL with MSI as source */
-  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSE | RCC_OSCILLATORTYPE_MSI;
+  /** Configure the main internal regulator output voltage
+  */
+  if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1) != HAL_OK) {
+    Error_Handler();
+  }
+
+  /* Configure LSE Drive Capability */
+  HAL_PWR_EnableBkUpAccess();
+  __HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_LOW);
+
+  /** Initializes the RCC Oscillators according to the specified parameters
+  * in the RCC_OscInitTypeDef structure.
+  */
+  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI | RCC_OSCILLATORTYPE_LSE
+                                     | RCC_OSCILLATORTYPE_MSI;
   RCC_OscInitStruct.LSEState = RCC_LSE_ON;
+  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
+  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
   RCC_OscInitStruct.MSIState = RCC_MSI_ON;
+  RCC_OscInitStruct.MSICalibrationValue = 0;
   RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_6;
-  RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;
   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_MSI;
   RCC_OscInitStruct.PLL.PLLM = 1;
   RCC_OscInitStruct.PLL.PLLN = 40;
   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV7;
   RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
   RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
-
   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
     Error_Handler();
   }
@@ -96,11 +110,14 @@ WEAK void SystemClock_Config(void)
   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
+
   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK) {
     Error_Handler();
   }
 
-  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USB;
+  /* Initializes the peripherals clock */
+  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPUART1 | RCC_PERIPHCLK_USB;
+  PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_HSI;
   PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLLSAI1;
   PeriphClkInit.PLLSAI1.PLLSAI1Source = RCC_PLLSOURCE_MSI;
   PeriphClkInit.PLLSAI1.PLLSAI1M = 1;
@@ -112,10 +129,6 @@ WEAK void SystemClock_Config(void)
   if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) {
     Error_Handler();
   }
-  /* Configure the main internal regulator output voltage */
-  if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1) != HAL_OK) {
-    Error_Handler();
-  }
   /* Enable MSI Auto calibration */
   HAL_RCCEx_EnableMSIPLLMode();
 }