** 源代码和开发文档地址：**
https://gitee.com/mftang/n32-g45-xvl-stb.git

5 串口

5.1 需求

使用UART 1 实现数据发送和接收功能，使用中断实现接收数据

5.2 功能实现

串口配置步骤如下：

step -1: 配置 TX 和 RX IO 接口属性

/*******************************************************************************
 Board Debug UART IO: UART-1
*******************************************************************************/
​
#define  DEBUG_UART           USART1
​
#define  DEBUG_GPIO           GPIOA
#define  DEBUG_RxPin          GPIO_PIN_10
#define  DEBUG_TxPin          GPIO_PIN_9
​
#define  RCC_DEBUG_UART_CLK       RCC_APB2_PERIPH_USART1
#define  RCC_DEBUG_GPIO_CLK       RCC_APB2_PERIPH_GPIOA
​
#define  GPIO_APBxClkCmd          RCC_EnableAPB2PeriphClk
#define  USART_APBxClkCmd         RCC_EnableAPB2PeriphClk
​
#define  DEBUG_USART_IRQn         USART1_IRQn
#define  DEBUG_IRQHandler         USART1_IRQHandler
​
static void Board_RCC_Configuration(void)
{
    /* Enable GPIO clock */
    GPIO_APBxClkCmd(RCC_DEBUG_GPIO_CLK | RCC_APB2_PERIPH_AFIO, ENABLE);
}
​
static void Board_GPIO_Configuration(void)
{
    GPIO_InitType GPIO_InitStructure;
​
    /* Configure USARTx Tx as alternate function push-pull */
    GPIO_InitStructure.Pin        = DEBUG_TxPin;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF_PP;
    GPIO_InitPeripheral(DEBUG_GPIO, &GPIO_InitStructure);
​
    /* Configure USARTx Rx as input floating */
    GPIO_InitStructure.Pin       = DEBUG_RxPin;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_InitPeripheral(DEBUG_GPIO, &GPIO_InitStructure);
}

step-2: 配置串口相关寄存区参数

void uart_Init( USART_Module* USARTx, uint32_t baud)
{
    USART_InitType USART_InitStructure;
    
    /* Enable UART Clock */
    USART_APBxClkCmd(RCC_DEBUG_UART_CLK, ENABLE);
    
    /* USARTy and USARTz configuration --------------------------------------------*/
    USART_InitStructure.BaudRate            = baud;
    USART_InitStructure.WordLength          = USART_WL_8B;
    USART_InitStructure.StopBits            = USART_STPB_1;
    USART_InitStructure.Parity              = USART_PE_NO;
    USART_InitStructure.HardwareFlowControl = USART_HFCTRL_NONE;
    USART_InitStructure.Mode                = USART_MODE_RX | USART_MODE_TX;
​
    /* Configure USARTx */
    USART_Init(USARTx, &USART_InitStructure);
    
    USART_ConfigInt(USARTx, USART_INT_RXDNE, ENABLE);
    
    /* Enable the USARTx */
    USART_Enable(USARTx, ENABLE);
    
}
​
static void Board_NVIC_Configuration(void)
{
    NVIC_InitType NVIC_InitStructure;
​
    /* Configure the NVIC Preemption Priority Bits */
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
​
    /* Enable the USARTy Interrupt */
    NVIC_InitStructure.NVIC_IRQChannel            = DEBUG_USART_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd         = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}
​

step-3： 实现发送函数

void uart_SendByte( USART_Module* USARTx, uint8_t _byte)
{
    USART_SendData(USARTx, _byte);
    while (USART_GetFlagStatus(USARTx, USART_FLAG_TXDE) == RESET);
}

step-4: 实现接收中断函数

void DEBUG_IRQHandler(void)
{
    uint8_t _byte = USART_ReceiveData(DEBUG_UART);
    RxBuffer1[count++] =  _byte;
    if ( count >= 128 )
    {
       count = 0;
    }
    DEBUG_UART->STS &= ~ USART_STS_RXDNE;
}

5.3 测试

UART 相关寄存器的数据