Add STM32F042K6U6 Support

Signed-off-by: jackb60 <40903548+jackb60@users.noreply.github.com>

Author: jackb60

variants/STM32F0xx/F042K(4-6)U/generic_clock.c

@@ -20,8 +20,45 @@
   */
 WEAK void SystemClock_Config(void)
 {
-  /* SystemClock_Config can be generated by STM32CubeMX */
-#warning "SystemClock_Config() is empty. Default clock at reset is used."
+  RCC_OscInitTypeDef RCC_OscInitStruct = {};
+  RCC_ClkInitTypeDef RCC_ClkInitStruct = {};
+  RCC_PeriphCLKInitTypeDef PeriphClkInit = {};
+
+  /** Initializes the RCC Oscillators according to the specified parameters
+  * in the RCC_OscInitTypeDef structure.
+  */
+  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_HSI48;
+  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
+  RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;
+  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
+  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
+  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
+  {
+    Error_Handler();
+  }
+
+  /** Initializes the CPU, AHB and APB buses clocks
+  */
+  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
+                              |RCC_CLOCKTYPE_PCLK1;
+  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI48;
+  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
+  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
+
+  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
+  {
+    Error_Handler();
+  }
+  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USB|RCC_PERIPHCLK_USART1
+                              |RCC_PERIPHCLK_I2C1;
+  PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK1;
+  PeriphClkInit.I2c1ClockSelection = RCC_I2C1CLKSOURCE_HSI;
+  PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_HSI48;
+
+  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
+  {
+    Error_Handler();
+  }
 }
 
 #endif /* ARDUINO_GENERIC_* */