Change clock setup for Generic F411's

System clock is now running at 96 MHz (and not 100 MHz) to keep compatibility with USB, that requires a 48 MHz clock. The expected external crystal/clock frequency can now be redefined at compile time.

Author: MCUdude

variants/Generic_F411Rx/variant.cpp

@@ -143,21 +143,21 @@ static uint8_t SetSysClock_PLL_HSE(uint8_t bypass)
 
   RCC_OscInitStruct.PLL.PLLState        = RCC_PLL_ON;
   RCC_OscInitStruct.PLL.PLLSource       = RCC_PLLSOURCE_HSE;
-  RCC_OscInitStruct.PLL.PLLM            = 8;             // VCO input clock = 1 MHz (8 MHz / 8)
-  RCC_OscInitStruct.PLL.PLLN            = 336;           // VCO output clock = 336 MHz (1 MHz * 336)
-  RCC_OscInitStruct.PLL.PLLP            = RCC_PLLP_DIV4; // PLLCLK = 84 MHz (336 MHz / 4)
-  RCC_OscInitStruct.PLL.PLLQ            = 7;             // USB clock = 48 MHz (336 MHz / 7) --> OK for USB
+  RCC_OscInitStruct.PLL.PLLM            = HSE_VALUE / 1000000L; // Expects an 8 MHz external clock by default. Redefine HSE_VALUE if not
+  RCC_OscInitStruct.PLL.PLLN            = 192;                  // VCO output clock = 192 MHz (1 MHz * 192)
+  RCC_OscInitStruct.PLL.PLLP            = RCC_PLLP_DIV2;        // PLLCLK = 96 MHz (192 MHz / 2)
+  RCC_OscInitStruct.PLL.PLLQ            = 4;                    // USB clock = 48 MHz (192 MHz / 4)
   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
     return 0; // FAIL
   }
 
   // Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers
   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2;
-  RCC_ClkInitStruct.SYSCLKSource   = RCC_SYSCLKSOURCE_PLLCLK; // 84 MHz
-  RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;         // 84 MHz
-  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;           // 42 MHz
-  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;           // 84 MHz
-  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) {
+  RCC_ClkInitStruct.SYSCLKSource   = RCC_SYSCLKSOURCE_PLLCLK; // 96 MHz
+  RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;         // 96 MHz
+  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;           // 48 MHz
+  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;           // 96 MHz
+  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3) != HAL_OK) {
     return 0; // FAIL
   }
 
@@ -194,20 +194,20 @@ uint8_t SetSysClock_PLL_HSI(void)
   RCC_OscInitStruct.PLL.PLLState        = RCC_PLL_ON;
   RCC_OscInitStruct.PLL.PLLSource       = RCC_PLLSOURCE_HSI;
   RCC_OscInitStruct.PLL.PLLM            = 16;            // VCO input clock = 1 MHz (16 MHz / 16)
-  RCC_OscInitStruct.PLL.PLLN            = 336;           // VCO output clock = 336 MHz (1 MHz * 336)
-  RCC_OscInitStruct.PLL.PLLP            = RCC_PLLP_DIV4; // PLLCLK = 84 MHz (336 MHz / 4)
-  RCC_OscInitStruct.PLL.PLLQ            = 7;             // USB clock = 48 MHz (336 MHz / 7) --> freq is ok but not precise enough
+  RCC_OscInitStruct.PLL.PLLN            = 192;           // VCO output clock = 192 MHz (1 MHz * 192)
+  RCC_OscInitStruct.PLL.PLLP            = RCC_PLLP_DIV2; // PLLCLK = 96 MHz (192 MHz / 2)
+  RCC_OscInitStruct.PLL.PLLQ            = 4;             // USB clock = 48 MHz (192 MHz / 4)
   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
     return 0; // FAIL
   }
 
   /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */
   RCC_ClkInitStruct.ClockType      = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
-  RCC_ClkInitStruct.SYSCLKSource   = RCC_SYSCLKSOURCE_PLLCLK; // 84 MHz
-  RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;         // 84 MHz
-  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;           // 42 MHz
-  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;           // 84 MHz
-  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) {
+  RCC_ClkInitStruct.SYSCLKSource   = RCC_SYSCLKSOURCE_PLLCLK; // 96 MHz
+  RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;         // 96 MHz
+  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;           // 48 MHz
+  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;           // 96 MHz
+  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3) != HAL_OK) {
     return 0; // FAIL
   }