stm32f103 串口1 调试正常，串口3不能发送出数据，请高手们帮我看看，什么问题，谢谢

[njtxyq]

下面是串口1和串口3的程序，串口3由PB10(TXD)和PB11(RXD),组成，现在串口3数据发送不出来。不知哪里有问题，请高手指教。

void uart_init(u32 bound)
{ // GPIO 端口设置
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE); USART_DeInit(USART1); //复位串口1
USART_DeInit(USART3); //复位串口3
//USART1_TX PA.9
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA.9
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure); //PA9

//USART1_RX PA.10
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING；
GPIO_Init(GPIOA, &GPIO_InitStructure);
//Usart1
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ； NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;；
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

USART_InitStructure.USART_BaudRate = bound;// 设置波特率
USART_InitStructure.USART_WordLength = USART_WordLength_9b;//8位数据1位奇数校验
USART_InitStructure.USART_StopBits = USART_StopBits_1;//1个停止位
USART_InitStructure.USART_Parity = USART_Parity_Odd; // USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;// USART_InitStructure.USART_Mode =/*SART_Mode_Rx |*/ USART_Mode_Tx;

USART_Init(USART1, &USART_InitStructure); //
USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);//
USART_Cmd(USART1, ENABLE);

// =======================usart 3 I/O PB.10=>TXD, PB.11==>RXD Begin ================
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE); //

//USART3_Txd PB.10
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; //PB.10
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOB, &GPIO_InitStructure);

//USART3_RX PB.11
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//
GPIO_Init(GPIOB, &GPIO_InitStructure);
// =======================usart 3 I/O PB10=>TXD, PB11==>RXD End ================

USART_InitStructure.USART_BaudRate = bound;//波特率19200;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;// USART_InitStructure.USART_StopBits = USART_StopBits_1;//
USART_InitStructure.USART_Parity = USART_Parity_No; // USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;// USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_Init(USART3, &USART_InitStructure);

NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;// NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure); //¸

USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);//
USART_Cmd(USART3, ENABLE);
}

发送程序：
int txd_fs3(u8 ch) {
while((USART3->SR&0X40)==0)
USART3->DR = (u8) ch;
return ch;
}
在main.c中调用
uart_init(19200）；
txd_fs3(0x45）；
txd_fs3(0x45）；

串口3数据发送不出来。不知问题在什么地方？

[默寞]

没仔细看stm32f103的引脚定义，不过之前遇到过一个问题是TXD3与RXD3引脚映射问题，也就是说TXD3有可能默认不是映射到PB.10，所以初始化PB.10实际没有和UART模块连起来。 这个看看手册检查一下吧。

[mangoalx]

发送程序：
int txd_fs3(u8 ch)  {      
  while((USART3->SR&0X40)==0) 
    USART3->DR = (u8) ch;      
  return ch;
}

很明显这里有问题。while 语句是用来等待串口发送空闲的，你漏掉了一个 ；，结果就成了串口发送忙时循环送数据，如果闲就跳过。。。 while 语句后面加个； 即： while((USART3->SR&0X40)==0)；