STM32F407ZE开发板实现使用串口USART1接收、发送字符串实例
具体代码及解析如下:
main.c部分
- #include <stm32f4xx.h>
- #include "led.h"
- #include "ustart.h"
- #include <string.h>
- int main()
- {
- LED_Init();
- USART1_Init();
- USART_SendString(USART1, "Hello world!\r\n");
- while(1)
- {
- if(Receive_Flag == 1) //接收数据标志位等于1(接收完毕,停止接收)
- Receive_Flag = 0; //接收数据标志位置0(可以开始接收)
- }
- }
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ustart.h部分
- #ifndef USTART_H
- #define USTART_H
- #include <stm32f4xx.h>
- #include <stm32f4xx_usart.h>
- #include <stdio.h>
- #include "sys.h"
- extern char USART1_ReceiveData[50]; //接收PC端发送过来的字符
- extern int Receive_Flag;
- void USART1_Init();
- void USART_SendString(USART_TypeDef* USARTx, char *DataString);
- #endif
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ustart.c部分
- #include "ustart.h"
- #include <string.h>
- int fputc(int ch, FILE *f)
- {
- /* 发送一个字节数据到串口 */
- USART_SendData(USART1, (uint8_t) ch); //程序开始时,会发送一次数据,ch是系统分配的(可能是0),串口会显示大概两个空格的内容
- /* 等待发送完毕 */
- while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
- return (ch);
- }
- void USART1_Init()
- {
- GPIO_InitTypeDef GPIOInit_Struct;
- USART_InitTypeDef USARTInit_Struct;
- NVIC_InitTypeDef USARTNVIC_Struct;
-
- //1、使能时钟
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
-
- //2、初始化对应的IO引脚复用为USART1功能
- RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE);
-
- GPIOInit_Struct.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
- GPIOInit_Struct.GPIO_Mode = GPIO_Mode_AF;
- GPIOInit_Struct.GPIO_OType = GPIO_OType_PP;
- GPIOInit_Struct.GPIO_Speed = GPIO_Fast_Speed;
- GPIOInit_Struct.GPIO_PuPd = GPIO_PuPd_UP;
- GPIO_Init(GPIOA,&GPIOInit_Struct);
-
- //将PA9 PA10复用为USART1功能
- GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_USART1);
- GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1);
-
- //3、USART1初始化
- USARTInit_Struct.USART_BaudRate = 115200; //波特率
- USARTInit_Struct.USART_Parity = USART_Parity_No; //无校验位
- USARTInit_Struct.USART_StopBits = USART_StopBits_1; //1位停止位
- USARTInit_Struct.USART_WordLength = USART_WordLength_8b; //8位数据位
- USARTInit_Struct.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //收发模式
- USARTInit_Struct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬件控制流
- USART_Init(USART1,&USARTInit_Struct);
-
- //开启串口终端
- USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);
-
- USARTNVIC_Struct.NVIC_IRQChannel = USART1_IRQn;//stm32f4xx.h
- USARTNVIC_Struct.NVIC_IRQChannelPreemptionPriority = 0;
- USARTNVIC_Struct.NVIC_IRQChannelSubPriority = 0;
- USARTNVIC_Struct.NVIC_IRQChannelCmd = ENABLE;
- NVIC_Init(&USARTNVIC_Struct);
-
- //4、开启串口
- USART_Cmd(USART1,ENABLE);
- }
- void USART_SendString(USART_TypeDef* USARTx, char *DataString)
- {
- int i = 0;
- USART_ClearFlag(USARTx,USART_FLAG_TC); //发送字符前清空标志位(否则缺失字符串的第一个字符)
- while(DataString<i> != '\0') //字符串结束符
- {
- USART_SendData(USARTx,DataString<i>); //每次发送字符串的一个字符
- while(USART_GetFlagStatus(USARTx,USART_FLAG_TC) == 0); //等待数据发送成功
- USART_ClearFlag(USARTx,USART_FLAG_TC); //发送字符后清空标志位
- i++;
- }
- }
- char USART_ReceiveString[50]; //接收PC端发送过来的字符
- int Receive_Flag = 0; //接收消息标志位
- int Receive_sum = 0; //数组下标
- void USART1_IRQHandler(void)
- {
- if(USART_GetITStatus(USART1,USART_IT_RXNE) == 1) //USART_FLAG_RXNE判断数据,== 1则有数据
- {
- if(Receive_sum > 49) //数组能存放50个字节的数据
- {
- USART_ReceiveString[49] = '\0'; //数据字节超过50位时,将最后一位设置为\0
- Receive_Flag = 1; //接收标志位置1,停止接收数据
- Receive_sum = 0; //数组下标置0
- }
-
- if(Receive_Flag == 0) //接收标志位等于0,开始接收数据
- {
- USART_ReceiveString[Receive_sum] = USART_ReceiveData(USART1); //通过USART1串口接收字符
- Receive_sum++; //数组下标++
- }
-
- if(Receive_sum >= 2) //数组下标大于2
- {
- if(USART_ReceiveString[Receive_sum-2] == '\r' && USART_ReceiveString[Receive_sum-1] == '\n' )
- {
- USART_ReceiveString[Receive_sum-1] = '\0';
- USART_ReceiveString[Receive_sum-2] = '\0';
- Receive_Flag = 1; //接收标志位置1,停止接收数据
- Receive_sum = 0; //数组下标置0
- printf("%s\r\n",USART_ReceiveString);
- if(strcmp(USART_ReceiveString,"hello") == 0)
- {
- PFout(9) = !PFout(9);
- }
- if(strcmp(USART_ReceiveString,"world") == 0)
- {
- PFout(10) = !PFout(10);
- }
- if(strcmp(USART_ReceiveString,"jiajia") == 0)
- {
- PEout(13) = !PEout(13);
- }
- if(strcmp(USART_ReceiveString,"haha") == 0)
- {
- PEout(14) = !PEout(14);
- }
- }
- }
- USART_ClearITPendingBit(USART1,USART_IT_RXNE); //接收后先清空标志位
- }
- }</i></i>
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led.h部分
- #ifndef _LED_H_
- #define _LED_H_
- #include <stm32f4xx.h>
- #include "sys.h"
- void LED_Init(void);
- #endif
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led.c部分
- #include "led.h"
- void LED_Init(void)
- {
- GPIO_InitTypeDef aaa;
-
- //1、先开启对应用到的模块时钟节拍
- RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF,ENABLE);
- RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE,ENABLE);//PE组时钟
- //2、可以初始化配置GPIO F组的9号引脚
- aaa.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
- aaa.GPIO_Mode = GPIO_Mode_OUT;//输出模式
- aaa.GPIO_Speed = GPIO_Fast_Speed;//快速 点灯和引脚速度无关
- aaa.GPIO_OType = GPIO_OType_PP;//推挽输出
- aaa.GPIO_PuPd = GPIO_PuPd_UP;//内部上拉
- GPIO_Init(GPIOF,&aaa);
-
-
- aaa.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_14;
- GPIO_Init(GPIOE,&aaa);
-
- //初始化完成 灭掉4盏灯
- PFout(9) = 1;
- PFout(10) = 1;
- PEout(13) = 1;
- PEout(14) = 1;
- }
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sys.h部分
- #ifndef __SYS_H
- #define __SYS_H
- #include "stm32f4xx.h"
- //IO口操作宏定义
- #define BITBAND(addr, bitnum) ((addr & 0xF0000000)+0x2000000+((addr & 0xFFFFF)<<5)+(bitnum<<2))
- #define MEM_ADDR(addr) *((volatile unsigned long *)(addr))
- #define BIT_ADDR(addr, bitnum) MEM_ADDR(BITBAND(addr, bitnum))
- //IO口地址映射
- #define GPIOA_ODR_Addr (GPIOA_BASE+20) //0x40020014
- #define GPIOB_ODR_Addr (GPIOB_BASE+20) //0x40020414
- #define GPIOC_ODR_Addr (GPIOC_BASE+20) //0x40020814
- #define GPIOD_ODR_Addr (GPIOD_BASE+20) //0x40020C14
- #define GPIOE_ODR_Addr (GPIOE_BASE+20) //0x40021014
- #define GPIOF_ODR_Addr (GPIOF_BASE+20) //0x40021414
- #define GPIOG_ODR_Addr (GPIOG_BASE+20) //0x40021814
- #define GPIOH_ODR_Addr (GPIOH_BASE+20) //0x40021C14
- #define GPIOI_ODR_Addr (GPIOI_BASE+20) //0x40022014
- #define GPIOA_IDR_Addr (GPIOA_BASE+16) //0x40020010
- #define GPIOB_IDR_Addr (GPIOB_BASE+16) //0x40020410
- #define GPIOC_IDR_Addr (GPIOC_BASE+16) //0x40020810
- #define GPIOD_IDR_Addr (GPIOD_BASE+16) //0x40020C10
- #define GPIOE_IDR_Addr (GPIOE_BASE+16) //0x40021010
- #define GPIOF_IDR_Addr (GPIOF_BASE+16) //0x40021410
- #define GPIOG_IDR_Addr (GPIOG_BASE+16) //0x40021810
- #define GPIOH_IDR_Addr (GPIOH_BASE+16) //0x40021C10
- #define GPIOI_IDR_Addr (GPIOI_BASE+16) //0x40022010
- //STM32中 对寄存器的访问 是不能单独访问寄存器的单个bit 只能以32bit地址访问寄存器
- //这些位为只写形式,只能在字(word)--4byte、半字2byte 或字节模式下访问
- //IO口操作,只对单一的IO口!
- //确保n的值小于16!
- #define PAout(n) BIT_ADDR(GPIOA_ODR_Addr,n) //输出
- #define PAin(n) BIT_ADDR(GPIOA_IDR_Addr,n) //输入
- #define PBout(n) BIT_ADDR(GPIOB_ODR_Addr,n) //输出
- #define PBin(n) BIT_ADDR(GPIOB_IDR_Addr,n) //输入
- #define PCout(n) BIT_ADDR(GPIOC_ODR_Addr,n) //输出
- #define PCin(n) BIT_ADDR(GPIOC_IDR_Addr,n) //输入
- #define PDout(n) BIT_ADDR(GPIOD_ODR_Addr,n) //输出
- #define PDin(n) BIT_ADDR(GPIOD_IDR_Addr,n) //输入
- #define PEout(n) BIT_ADDR(GPIOE_ODR_Addr,n) //输出
- #define PEin(n) BIT_ADDR(GPIOE_IDR_Addr,n) //输入
- #define PFout(n) BIT_ADDR(GPIOF_ODR_Addr,n) //输出
- #define PFin(n) BIT_ADDR(GPIOF_IDR_Addr,n) //输入
- #define PGout(n) BIT_ADDR(GPIOG_ODR_Addr,n) //输出
- #define PGin(n) BIT_ADDR(GPIOG_IDR_Addr,n) //输入
- #define PHout(n) BIT_ADDR(GPIOH_ODR_Addr,n) //输出
- #define PHin(n) BIT_ADDR(GPIOH_IDR_Addr,n) //输入
- #define PIout(n) BIT_ADDR(GPIOI_ODR_Addr,n) //输出
- #define PIin(n) BIT_ADDR(GPIOI_IDR_Addr,n) //输入
- #endif
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