基于STM32F103C6工程实现串口USART1功能，USART1串口TX为PA9,RX为PA10,配置一个USART1串口分为以下几步：
- 初时化IO配置
- 初时化USART NVIC配置
- 初时化USART参数
- 实现中断函数USART1_IRQHandler
- 实现串口发送函数USART1_Send_Data
- 主函数调用相关配置函数
Step 1: 初时化IO配置,初时化USART NVIC配置,初时化USART参数封装成一个函数
#include "stm32f10x_usart.h"
#include "stm32f10x.h"
#include
uint8_t rxBuf[40];
uint8_t rxLen;
/**
* @brief USART1串口初时化
*
*
* @param uint32_t baudrate[in]:设置波特率
* @retval None
*/
void Usart1_Init(uint32_t baudrate)
{
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
/* 初时化串口前，先将相应的时钟打开 */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA,ENABLE);
/* 初时化USART1 TX PA9引脚设为复用推挽输出 */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA,&GPIO_InitStructure);
/* 初时化USART1 RX PA10引脚为浮空输入 */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA,&GPIO_InitStructure);
/* USART1 NVIC初时化 */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); /*!< 设置NVIC中断分组2:2位抢占优先级，2位响应优先级 0-3; */
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn; /*!< USART1中断通道USART1_IRQn */
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3; /*!< 抢占优先级3 */
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; /*!< 子优先级3 */
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; /*!< IRQ使能通道 */
NVIC_Init(&NVIC_InitStructure); /*!< 初时化NVIC寄存器 */
/* USART初时化设置 */
USART_InitStructure.USART_BaudRate = baudrate; /*!< 设置波特率 */
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_WordLength = USART_WordLength_8b; /*!< 8位数据*/
USART_InitStructure.USART_StopBits = USART_StopBits_1; /*!< 1位停止位 */
USART_InitStructure.USART_Parity = USART_Parity_No; /*!< 无校验位 */
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; /*!< 收发模式*/
USART_Init(USART1,&USART_InitStructure); /*!< 初时化串口1 */
/* 开启串口1接收中断 */
USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);
/* 使能串口1 */
USART_Cmd(USART1,ENABLE);
}
Step 2: 实现中断函数USART1_IRQHandler
/**
* @brief USART1串口中断函数
*
*
* @param None
* @retval None
*/
void USART1_IRQHandler(void)
{
/* 暂存接收结果 */
uint8_t result;
/* @note
* - PE (Parity error), FE (Framing error), NE (Noise error), ORE (OverRun
* error) and IDLE (Idle line detected) pending bits are cleared by
* software sequence: a read operation to USART_SR register
* (USART_GetITStatus()) followed by a read operation to USART_DR register
* (USART_ReceiveData()).
* - RXNE pending bit can be also cleared by a read to the USART_DR register
* (USART_ReceiveData()).
*/
/* 检查是否为USART1接收中断 */
if(USART_GetITStatus(USART1,USART_IT_RXNE) != RESET)
{
result = USART_ReceiveData(USART1);
if(rxLen < 20)
{
rxBuf[rxLen] = result;
rxLen++;
}
}
/* 溢出发生时，先读SR,再读DR，解决中断不进入问题*/
else if(USART_GetFlagStatus(USART1,USART_IT_ORE) == SET)
{
USART_ClearFlag(USART1,USART_IT_ORE);
USART_ReceiveData(USART1);
}
}
Step 3:实现串口发送函数USART1_Send_Data
/**
* @brief USART1串口发送函数
*
*
* @param uint8_t *buf[in]:待发送的数据buffer
* @param uint16_t len:发送的数据长度
* @retval None
*/
void USART1_Send_Data(uint8_t *buf,uint16_t len)
{
for(uint16_t i = 0; i
{
/*- TC pending bit can be also cleared by software sequence: a read
* operation to USART_SR register (USART_GetITStatus()) followed by a write
* operation to USART_DR register (USART_SendData()).
* - TXE pending bit is cleared only by a write to the USART_DR register
* (USART_SendData()).
*/
while(USART_GetFlagStatus(USART1,USART_FLAG_TC)); /*!<发送是否完成*/
USART_SendData(USART1,buf);
}
}
Step 4:主函数调用相关配置函数
/**
* @brief 主函数，程序的入口
*
*
* @param None
* @retval int:不用理会，对于嵌入式系统，永远都不会返回
*/
int main(void)
{
Usart1_Init(9600);
for(;;)
{
if(rxLen >= 20)
{
USART1_Send_Data(rxBuf,20);
rxLen = 0;
}
}
}
串口功能完成，那么如何实现printf函数功能呢，重定义fputc函数
//重定义fputc函数
int fputc(int ch, FILE *f)
{
while((USART1->SR&0X40)==0);
USART1->DR = (u8) ch;
return ch;
}
此时还需要勾选Use MicroLib选项
另一种方法不需要勾选Use MicroLib选项，如下：
/* 加入以下代码,支持printf函数,而不需要选择use MicroLIB */
#ifdef DEBUG
#pragma import(__use_no_semihosting)
//标准库需要的支持函数
struct __FILE
{
int handle;
};
FILE __stdout;
//定义_sys_exit()以避免使用半主机模式
void _sys_exit(int x)
{
x = x;
}
//重定义fputc函数
int fputc(int ch, FILE *f)
{
while((USART1->SR&0X40)==0);
USART1->DR = (u8) ch;
return ch;
}
#endif
断言功能实现，首先得定义宏USE_FULL_ASSERT打开断言功能，然后实现函
数assert_failed
#if USE_FULL_ASSERT
void assert_failed(uint8_t* file, uint32_t line)
{
printf("rnfile path is %s,error line is %drn",file,line);
while(1);
}
#endif
基于STM32F103C6工程实现串口USART1功能，USART1串口TX为PA9,RX为PA10,配置一个USART1串口分为以下几步：
- 初时化IO配置
- 初时化USART NVIC配置
- 初时化USART参数
- 实现中断函数USART1_IRQHandler
- 实现串口发送函数USART1_Send_Data
- 主函数调用相关配置函数
Step 1: 初时化IO配置,初时化USART NVIC配置,初时化USART参数封装成一个函数
#include "stm32f10x_usart.h"
#include "stm32f10x.h"
#include
uint8_t rxBuf[40];
uint8_t rxLen;
/**
* @brief USART1串口初时化
*
*
* @param uint32_t baudrate[in]:设置波特率
* @retval None
*/
void Usart1_Init(uint32_t baudrate)
{
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
/* 初时化串口前，先将相应的时钟打开 */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA,ENABLE);
/* 初时化USART1 TX PA9引脚设为复用推挽输出 */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA,&GPIO_InitStructure);
/* 初时化USART1 RX PA10引脚为浮空输入 */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA,&GPIO_InitStructure);
/* USART1 NVIC初时化 */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); /*!< 设置NVIC中断分组2:2位抢占优先级，2位响应优先级 0-3; */
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn; /*!< USART1中断通道USART1_IRQn */
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3; /*!< 抢占优先级3 */
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; /*!< 子优先级3 */
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; /*!< IRQ使能通道 */
NVIC_Init(&NVIC_InitStructure); /*!< 初时化NVIC寄存器 */
/* USART初时化设置 */
USART_InitStructure.USART_BaudRate = baudrate; /*!< 设置波特率 */
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_WordLength = USART_WordLength_8b; /*!< 8位数据*/
USART_InitStructure.USART_StopBits = USART_StopBits_1; /*!< 1位停止位 */
USART_InitStructure.USART_Parity = USART_Parity_No; /*!< 无校验位 */
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; /*!< 收发模式*/
USART_Init(USART1,&USART_InitStructure); /*!< 初时化串口1 */
/* 开启串口1接收中断 */
USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);
/* 使能串口1 */
USART_Cmd(USART1,ENABLE);
}
Step 2: 实现中断函数USART1_IRQHandler
/**
* @brief USART1串口中断函数
*
*
* @param None
* @retval None
*/
void USART1_IRQHandler(void)
{
/* 暂存接收结果 */
uint8_t result;
/* @note
* - PE (Parity error), FE (Framing error), NE (Noise error), ORE (OverRun
* error) and IDLE (Idle line detected) pending bits are cleared by
* software sequence: a read operation to USART_SR register
* (USART_GetITStatus()) followed by a read operation to USART_DR register
* (USART_ReceiveData()).
* - RXNE pending bit can be also cleared by a read to the USART_DR register
* (USART_ReceiveData()).
*/
/* 检查是否为USART1接收中断 */
if(USART_GetITStatus(USART1,USART_IT_RXNE) != RESET)
{
result = USART_ReceiveData(USART1);
if(rxLen < 20)
{
rxBuf[rxLen] = result;
rxLen++;
}
}
/* 溢出发生时，先读SR,再读DR，解决中断不进入问题*/
else if(USART_GetFlagStatus(USART1,USART_IT_ORE) == SET)
{
USART_ClearFlag(USART1,USART_IT_ORE);
USART_ReceiveData(USART1);
}
}
Step 3:实现串口发送函数USART1_Send_Data
/**
* @brief USART1串口发送函数
*
*
* @param uint8_t *buf[in]:待发送的数据buffer
* @param uint16_t len:发送的数据长度
* @retval None
*/
void USART1_Send_Data(uint8_t *buf,uint16_t len)
{
for(uint16_t i = 0; i
{
/*- TC pending bit can be also cleared by software sequence: a read
* operation to USART_SR register (USART_GetITStatus()) followed by a write
* operation to USART_DR register (USART_SendData()).
* - TXE pending bit is cleared only by a write to the USART_DR register
* (USART_SendData()).
*/
while(USART_GetFlagStatus(USART1,USART_FLAG_TC)); /*!<发送是否完成*/
USART_SendData(USART1,buf);
}
}
Step 4:主函数调用相关配置函数
/**
* @brief 主函数，程序的入口
*
*
* @param None
* @retval int:不用理会，对于嵌入式系统，永远都不会返回
*/
int main(void)
{
Usart1_Init(9600);
for(;;)
{
if(rxLen >= 20)
{
USART1_Send_Data(rxBuf,20);
rxLen = 0;
}
}
}
串口功能完成，那么如何实现printf函数功能呢，重定义fputc函数
//重定义fputc函数
int fputc(int ch, FILE *f)
{
while((USART1->SR&0X40)==0);
USART1->DR = (u8) ch;
return ch;
}
此时还需要勾选Use MicroLib选项
另一种方法不需要勾选Use MicroLib选项，如下：
/* 加入以下代码,支持printf函数,而不需要选择use MicroLIB */
#ifdef DEBUG
#pragma import(__use_no_semihosting)
//标准库需要的支持函数
struct __FILE
{
int handle;
};
FILE __stdout;
//定义_sys_exit()以避免使用半主机模式
void _sys_exit(int x)
{
x = x;
}
//重定义fputc函数
int fputc(int ch, FILE *f)
{
while((USART1->SR&0X40)==0);
USART1->DR = (u8) ch;
return ch;
}
#endif
断言功能实现，首先得定义宏USE_FULL_ASSERT打开断言功能，然后实现函
数assert_failed
#if USE_FULL_ASSERT
void assert_failed(uint8_t* file, uint32_t line)
{
printf("rnfile path is %s,error line is %drn",file,line);
while(1);
}
#endif
举报
