🧑‍💻 STM32G0Bx : Use PLLQ for USB clock (MarlinFirmware#23870)

Author: bigtreetech

buildroot/share/PlatformIO/variants/MARLIN_G0B1RE/variant_MARLIN_STM32G0B1RE.cpp

@@ -115,11 +115,11 @@ extern "C" {
   *            AHB Prescaler                  = 1
   *            APB1 Prescaler                 = 1
   *            PLL_M                          = 1
-  *            PLL_N                          = 16
-  *            PLL_R                          = 2
+  *            PLL_N                          = 24
+  *            PLL_R                          = 3
   *            PLL_P                          = 2
-  *            PLL_Q                          = 2
-  *            USB(Hz)                        = 48000000 (HSI48M)
+  *            PLL_Q                          = 4
+  *            USB(Hz)                        = 48000000 (PLLQ)
   * @param  None
   * @retval None
   */
@@ -129,22 +129,31 @@ WEAK void SystemClock_Config(void)
   RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
   RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
 
+  // Reset clock registers (in case bootloader has changed them)
+  RCC->CR |= RCC_CR_HSION;
+  while (!(RCC->CR & RCC_CR_HSIRDY))
+      ;
+  RCC->CFGR = 0x00000000;
+  RCC->CR = RCC_CR_HSION;
+  while (RCC->CR & RCC_CR_PLLRDY)
+      ;
+  RCC->PLLCFGR = 0x00001000;
+
   /** Configure the main internal regulator output voltage
   */
   HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1);
   /** Initializes the RCC Oscillators according to the specified parameters
   * in the RCC_OscInitTypeDef structure.
   */
-  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE|RCC_OSCILLATORTYPE_HSI48;
+  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
   RCC_OscInitStruct.HSEState = RCC_HSE_ON;
-  RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;
   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
   RCC_OscInitStruct.PLL.PLLM = RCC_PLLM_DIV1;
-  RCC_OscInitStruct.PLL.PLLN = 16;
+  RCC_OscInitStruct.PLL.PLLN = 24;
   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
-  RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
-  RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
+  RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV4;
+  RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV3;
   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
   {
     Error_Handler();
@@ -164,7 +173,7 @@ WEAK void SystemClock_Config(void)
   /** Initializes the peripherals clocks
   */
   PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USB;
-  PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_HSI48;
+  PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLL;
   if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
   {
     Error_Handler();