STM32H750如何才能把串口频率设置到2M以上？

经过多次测试，发现用STM32CubeMX生成的串口通信程序，串口波特率设置不能超过2M，如果大于2M在 HAL_StatusTypeDef UART_SetConfig(UART_HandleTypeDef *huart) 这个函数会报错！！

我的波特率设置是这样的
  huart1.Instance = USART1;
  huart1.Init.BaudRate = 2500000；//115200;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling = UART_OVERSAMPLING_8;
  huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  huart1.Init.ClockPrescaler = UART_PRESCALER_DIV1;//UART_PRESCALER_DIV1;
  huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;


这个是在波特率配置后  usartdiv 不满足条件进入  ret = HAL_ERROR;

    /* USARTDIV must be greater than or equal to 0d16 */
    if ((usartdiv >= UART_BRR_MIN)    (usartdiv <= UART_BRR_MAX))
    {
      brrtemp = (uint16_t)(usartdiv   0xFFF0U);
      brrtemp |= (uint16_t)((usartdiv   (uint16_t)0x000FU) >> 1U);
      huart->Instance->BRR = brrtemp;
    }
    else
    {
      ret = HAL_ERROR;
    }



下面是我的时钟配置

void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
  RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};

  /** Supply configuration update enable
  */
  HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);
  /** Configure the main internal regulator output voltage
  */
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE0);

  while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}
  /** Initializes the CPU, AHB and APB busses clocks
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSIState = RCC_HSI_DIV1;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 2;
  RCC_OscInitStruct.PLL.PLLN = 240;
  RCC_OscInitStruct.PLL.PLLP = 2;
  RCC_OscInitStruct.PLL.PLLQ = 2;
  RCC_OscInitStruct.PLL.PLLR = 2;
  RCC_OscInitStruct.PLL.PLLRGE = RCC_PLL1VCIRANGE_2;
  RCC_OscInitStruct.PLL.PLLVCOSEL = RCC_PLL1VCOWIDE;
  RCC_OscInitStruct.PLL.PLLFRACN = 0;
  if (HAL_RCC_OscConfig( RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
  /** Initializes the CPU, AHB and APB busses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2
                              |RCC_CLOCKTYPE_D3PCLK1|RCC_CLOCKTYPE_D1PCLK1;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV2;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV2;
  RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV2;

  if (HAL_RCC_ClockConfig( RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK)
  {
    Error_Handler();
  }
  PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_USART3|RCC_PERIPHCLK_USART2
                              |RCC_PERIPHCLK_UART4|RCC_PERIPHCLK_UART7
                              |RCC_PERIPHCLK_FDCAN|RCC_PERIPHCLK_USART1
                              |RCC_PERIPHCLK_UART8|RCC_PERIPHCLK_UART5
                              |RCC_PERIPHCLK_SPI4|RCC_PERIPHCLK_ADC
                              |RCC_PERIPHCLK_I2C4|RCC_PERIPHCLK_LPTIM1
                              |RCC_PERIPHCLK_CKPER;
  PeriphClkInitStruct.CkperClockSelection = RCC_CLKPSOURCE_HSI;
  PeriphClkInitStruct.Spi45ClockSelection = RCC_SPI45CLKSOURCE_D2PCLK1;
  PeriphClkInitStruct.FdcanClockSelection = RCC_FDCANCLKSOURCE_HSE;
  PeriphClkInitStruct.Usart234578ClockSelection = RCC_USART234578CLKSOURCE_D2PCLK1;
  PeriphClkInitStruct.Usart16ClockSelection = RCC_USART16CLKSOURCE_D2PCLK2;
  PeriphClkInitStruct.Lptim1ClockSelection = RCC_LPTIM1CLKSOURCE_D2PCLK1;
  PeriphClkInitStruct.I2c4ClockSelection = RCC_I2C4CLKSOURCE_D3PCLK1;
  PeriphClkInitStruct.AdcClockSelection = RCC_ADCCLKSOURCE_CLKP;
  if (HAL_RCCEx_PeriphCLKConfig( PeriphClkInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
}


串口的时钟 有120M ，理论上配置大于2M波特率应该没有问题，为什么实际上我配置后，在HAL_StatusTypeDef UART_SetConfig(UART_HandleTypeDef *huart) 这个函数会报错，？有没有高手解释一下！！