（3）stm32开发之串口的调试
今天把stm32的串口配置起来，把经验跟大家共享下
总的函数如下
void USART1Configuration(void)
{
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO | RCC_APB2Periph_USART1,ENABLE);
USART1_GPIO_Configuration();
USART1_Param_Configuration();
NVIC_Configuration(); /*串口使用中断方式才用到*/
//打开发送接收中断
USART_ITConfig(USART1, USART_IT_TXE, ENABLE);
USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
USART_Cmd(USART1,ENABLE); /*使能串口*/
}
时间配置就不讲了
首先是配置USART的GPIO口
/*******************************************************************************
* Name : UART1_GPIO_Configuration
* Deion : Configures the uart1 GPIO ports.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void USART1_GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
// Configure USART1_Tx as alternate push-pull
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
// Configure USART1_Rx as input floating
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
然后是配置串口参数
/*******************************************************************************
* Name : UART1_Configuration
* Deion : Configures the uart1
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void USART1_Param_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
USART_ClockInitTypeDef USART_ClockInitStructure;
USART_ClockInitStructure.USART_Clock = USART_Clock_Disable;
USART_ClockInitStructure.USART_CPOL = USART_CPOL_Low;
USART_ClockInitStructure.USART_CPHA = USART_CPHA_2Edge;
USART_ClockInitStructure.USART_LastBit = USART_LastBit_Disable;
/* Configure the USART1 synchronous paramters */
USART_ClockInit(USART1, &USART_ClockInitStructure);
USART_InitStructure.USART_BaudRate = 9600;
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;
/* Configure USART1 basic and asynchronous paramters */
USART_Init(USART1, &USART_InitStructure);
}
然后是在中断设置,需要修改stm32f10x_it.c 中的串口中断函数 并且需要修改void NVIC_Configuration(void)函数
修改NVIC_Configuration函数
/*******************************************************************************
* Name : NVIC_Configuration
* Deion : Configures NVIC and Vector Table base location.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
#ifdef VECT_TAB_RAM
/* Set the Vector Table base location at 0x20000000 */
NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
#else /* VECT_TAB_FLASH */
/* Set the Vector Table base location at 0x08000000 */
NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);
#endif
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);//
/* Enable the USART1 Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn; /*这个串口中断入口可以查询stm32f10.h得到看有哪些中断入口*/
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
串口中断处理函数文件
/* Private macro -------------------------------------------------------------*/
#define countof(a) (sizeof(a) / sizeof(*(a)))
/* Private variables ---------------------------------------------------------*/
uint8_t TxBuffer[160];
uint8_t RxBuffer[RxBufferSize];
uint8_t NbrOfDataToTransfer = TxBufferSize;
uint8_t NbrOfDataToRead = RxBufferSize;
uint8_t TxCounter = 0;
uint16_t RxCounter = 0;
//串口中断
void USART1_IRQHandler(void)
{
/*接收中断*/
u16 i;
if(USART_GetFlagStatus(USART1,USART_IT_RXNE)== SET)
{
i = USART_ReceiveData(USART1);
USART_SendData(USART1,i); /*回显*/
while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET)
{
}
}
//发送中断,很少用到
if (USART_GetITStatus(USART1, USART_IT_TXE) == SET)
{
USART_SendData(USART1, TxBuffer[TxCounter++]);
if (NbrOfDataToTransfer==TxCounter) /*最后一个字节不要，因为字符串最后一个是\0*/
{
//发送字节结束
USART_ITConfig(USART1, USART_IT_TXE, DISABLE);
}
}
}
至此 串口就可以工作起来了，但是还有很重要一点，就是编译时要打开target-Use MicroLIB勾上，就可以了。
发送中断应该说有两个一个是发送完中断,一个是缓冲区空中断,你说的问题应该是发生在缓冲区空中断中.
当发送一帧数据时,如果发生缓冲区空中断或发送完毕中断时,还有数据要继续发送,那就发送下一个数据,如果数据已经都发送完了,则处理方式上有点区别,如果用缓冲区空中断,则而将中断关闭,如果用发送完毕中断,则直接返回就可以了
但是要用到printf来打印到串口1的话，需要对printf重定向到usart1，printf函数不用到中断
/*******************************************************************************
* Function Name : int fputc(int ch, FILE *f)
* Description : Retargets the C library printf function to the USART.printf重定向
* Input : None
* Output : None
* Return : None
*******************************************************************************/
int fputc(int ch, FILE *f)
{
/* Write a character to the USART */
USART_SendData(USART1, (u8) ch);
/* Loop until the end of transmission */
while((USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET))
{
}
return ch;
}
/*******************************************************************************
* Function Name : int fgetc(FILE *f)
* Description : Retargets the C library printf function to the USART.fgetc重定向
* Input : None
* Output : None
* Return : 读取到的字符
*******************************************************************************/
int fgetc(FILE *f)
{
/* Loop until received a char */
while((USART_GetFlagStatus(USART1, USART_FLAG_RXNE) == RESET))
{
}
/* Read a character from the USART and RETURN */
return (USART_ReceiveData(USART1));
}
到这里，usart1就能打印出printf的内容了