stm32f103c8t6初始化usart3，pb10,pb11引脚代码

以下是使用STM32CubeMX生成的初始化代码，可以使用HAL库进行USART3的初始化，其中PB10和PB11分别对应USART3的TX和RX引脚。

/* USART3 init function */
void MX_USART3_UART_Init(void)
{
  huart3.Instance = USART3;
  huart3.Init.BaudRate = 115200;
  huart3.Init.WordLength = UART_WORDLENGTH_8B;
  huart3.Init.StopBits = UART_STOPBITS_1;
  huart3.Init.Parity = UART_PARITY_NONE;
  huart3.Init.Mode = UART_MODE_TX_RX;
  huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart3.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart3) != HAL_OK)
  {
    Error_Handler();
  }
}

/* USART3 GPIO Configuration    
PB10     ------> USART3_TX
PB11     ------> USART3_RX 
*/
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_10, GPIO_PIN_RESET);

  /*Configure GPIO pins : PB10 PB11 */
  GPIO_InitStruct.Pin = GPIO_PIN_10|GPIO_PIN_11;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF7_USART3;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
}