飞控串口通信接入linux

1.串口设置

2.串口接入

3.消息传输

4.消息透传

5.mavlink解析

1.mavlink库

将mavlink库添加至项目包含目录

2.常用mavlink消息

mavlink_heartbeat_t 心跳包

mavlink_attitude_t 姿态角、角速度

mavlink_gps_raw_int_t gps信息

mavlink_battery_status_t 电池状态

mavlink_vfr_hud_t 空速地速高度

6.全部代码

com.c

include "com.h"
/*struct termios
{
    unsigned short c_iflag;   //输入模式标志
    unsigned short c_oflag;   //输出模式标志-
    unsigned short c_cflag;   //控制模式标志
    unsigned short c_lflag;   //本地模式标志-
    unsigned char c_line;     //线路规程-
    unsigned char c_cc[NCC];  //控制特性
    speed_t c_ispeed;         //输入速度-
    speed_t c_ospeed;         //输出速度-
}
*/
/****************************************/
/************打开串口函数****************/
/****************************************/
int open_port(int com_port)
{
    int fd;
    /* 使用普通串口 */
    //char *dev[] = {"/dev/ttySAC0","/dev/ttySAC1","/dev/ttySAC2","/dev/ttySAC3"};<br />    /* 使用 USB 转串口 */
    char *dev[] = {"/dev/ttyUSB3", "/dev/ttyUSB1", "/dev/ttyUSB2"};

    printf("open dev [%s]\n",dev[com_port]);
    //O_NDELAY 同 O_NONBLOCK。
    fd = open(dev[com_port], O_RDWR|O_NOCTTY);
    if (fd < 0)
    {
        perror("open serial port"); 
        return(-1); 
    }

com.h

#ifndef _COM_H_
#define _COM_H_
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <unistd.h>
#include <termios.h>
#include <fcntl.h>
 
int set_com_config(int fd,int baud_rate,int data_bits, char parity, int stop_bits);
int open_port(int com_port);
 
#endif

main.c

#include "com.h" 
 
#define BUFFER_SIZE 1024      /*最大缓存区*/
 
//char *pstr[]={"NO1\n","NO2\n","NO3\n","NO4\n"}; 
int main(int argc, char *argv[])
{
	int fd;
	int i;
	char *read_buffer[BUFFER_SIZE];
	int read_buffer_size;
 
	//打开串口
	fd = open_port(0);
	//设置串口
    if(set_com_config(fd, 57600, 8, 'N', 1) < 0) /* 配置串口 */ 
    { 
        perror("set_com_config"); 
        return 1; 
    } 
 
	//发送数据
    do{
        for(i=0;i<1024;i++){
            sleep(1);
        }
	    do{
		    memset(read_buffer,0, BUFFER_SIZE);
	    	read_buffer_size = read(fd, read_buffer, BUFFER_SIZE);				
	    }while(!read_buffer_size);
		    printf("[0x%04x]\n",read_buffer[BUFFER_SIZE]);

	}while(1);
	close(fd);
	return 0;
}

test.c

#include <stdio.h>              // printf   
#include <fcntl.h>              // open   
#include <string.h>             // bzero   
#include <stdlib.h>             // exit   
#include <sys/times.h>          // times   
#include <sys/types.h>          // pid_t   
#include <termios.h>            //termios, tcgetattr(), tcsetattr()
#include <unistd.h>
#include <sys/ioctl.h>          // ioctl
 
#define TTY_DEV "/dev/ttyUSB3"   //端口路径
 
#define TIMEOUT_SEC(buflen,baud) (buflen*20/baud+2)  //接收超时   
#define TIMEOUT_USEC 0
 
//串口结构
typedef struct{
    char prompt;        //prompt after reciving data
    int  baudrate;      //baudrate
    char databit;       //data bits, 5, 6, 7, 8
    char debug;         //debug mode, 0: none, 1: debug
    char echo;          //echo mode, 0: none, 1: echo
    char fctl;          //flow control, 0: none, 1: hardware, 2: software
    char tty;           //tty: 0, 1, 2, 3, 4, 5, 6, 7
    char parity;        //parity 0: none, 1: odd, 2: even
    char stopbit;       //stop bits, 1, 2
    const int reserved; //reserved, must be zero
}portinfo_t;
typedef portinfo_t *pportinfo_t;
 
/**
 * 打开串口，返回文件描述符
 * pportinfo: 待设置的串口信息
*/
int PortOpen(pportinfo_t pportinfo);
 
/**
 * 设置串口
 * fdcom: 串口文件描述符， pportinfo： 待设置的串口信息
*/
int PortSet(int fdcom, const pportinfo_t pportinfo);
/**
 * 关闭串口
 * fdcom：串口文件描述符
*/
void PortClose(int fdcom);
 
/**
 * 发送数据
 * fdcom：串口描述符， data：待发送数据, datalen：数据长度
 * 返回实际发送长度
*/
int PortSend(int fdcom, char *data, int datalen);
 
/**
 * 接收数据
 * fdcom：串口描述符， data：接收缓冲区, datalen：接收长度, baudrate：波特率
 * 返回实际读入的长度
*/
int PortRecv(int fdcom, char *data, int datalen, int baudrate);
 
 
/******************************************* 
 *  获得端口名称 
********************************************/
char *get_ptty(pportinfo_t pportinfo)
{
    char *ptty;
 
    switch(pportinfo->tty){
        case '0':{
            ptty = TTY_DEV"0";
        }break;
        case '1':{
            ptty = TTY_DEV"1";
        }break;
        case '2':{
            ptty = TTY_DEV"2";
        }break;
    }
    return(ptty);
}
 
/******************************************* 
 *  波特率转换函数（请确认是否正确） 
********************************************/
int convbaud(unsigned long int baudrate)
{
    switch(baudrate){
        case 2400:
            return B2400;
        case 4800:
            return B4800;
        case 9600:
            return B9600;
        case 19200:
            return B19200;
        case 38400:
            return B38400;
        case 57600:
            return B57600;
        case 115200:
            return B115200;
        default:
            return B9600;
    }
}
 
/******************************************* 
 *  Setup comm attr 
 *  fdcom: 串口文件描述符，pportinfo: 待设置的端口信息（请确认） 
 * 
********************************************/
int PortSet(int fdcom, const pportinfo_t pportinfo)
{
    struct termios termios_old, termios_new;
    int     baudrate, tmp;
    char    databit, stopbit, parity, fctl;
 
    bzero(&termios_old, sizeof(termios_old));
    bzero(&termios_new, sizeof(termios_new));
    cfmakeraw(&termios_new);
    tcgetattr(fdcom, &termios_old);         //get the serial port attributions
 
    /*------------设置端口属性----------------*/
    //baudrates   
    baudrate = convbaud(pportinfo->baudrate);
    cfsetispeed(&termios_new, baudrate);        //填入串口输入端的波特率   
    cfsetospeed(&termios_new, baudrate);        //填入串口输出端的波特率   
    termios_new.c_cflag |= CLOCAL;              //控制模式，保证程序不会成为端口的占有者
    termios_new.c_cflag |= CREAD;               //控制模式，使能端口读取输入的数据
 
    // 控制模式:flow control
    fctl = pportinfo-> fctl;
    switch(fctl){
        case '0':{
            termios_new.c_cflag &= ~CRTSCTS;            //no flow control
        }break;
        case '1':{
            termios_new.c_cflag |= CRTSCTS;             //hardware flow control
        }break;
        case '2':{
            termios_new.c_iflag |= IXON | IXOFF |IXANY; //software flow control   
        }break;
    }
 
    //控制模式，data bits   
    termios_new.c_cflag &= ~CSIZE;      //控制模式，屏蔽字符大小位   
    databit = pportinfo -> databit;
    switch(databit){
        case '5':
            termios_new.c_cflag |= CS5;
        case '6':
            termios_new.c_cflag |= CS6;
        case '7':
            termios_new.c_cflag |= CS7;
        default:
            termios_new.c_cflag |= CS8;
    }
 
    //控制模式 parity check   
    parity = pportinfo -> parity;
    switch(parity){
        case '0':{
            termios_new.c_cflag &= ~PARENB;     //no parity check   
        }break;
        case '1':{
            termios_new.c_cflag |= PARENB;      //odd check   
            termios_new.c_cflag &= ~PARODD;
        }break;
        case '2':{
            termios_new.c_cflag |= PARENB;      //even check   
            termios_new.c_cflag |= PARODD;
        }break;
    }
 
    //控制模式，stop bits   
    stopbit = pportinfo -> stopbit;
    if(stopbit == '2'){
        termios_new.c_cflag |= CSTOPB;  //2 stop bits   
    }
    else{
        termios_new.c_cflag &= ~CSTOPB; //1 stop bits   
    }
 
    //other attributions default   
    termios_new.c_oflag &= ~OPOST;          //输出模式, 原始数据输出
    termios_new.c_cc[VMIN]  = 0;            //控制字符, 所要读取字符的最小数量
    termios_new.c_cc[VTIME] = 1;            //控制字符, 读取第一个字符的等待时间    unit: (1/10)second   
 
    tcflush(fdcom, TCIFLUSH);               //溢出的数据可以接收，但不读   
    tmp = tcsetattr(fdcom, TCSANOW, &termios_new);  //设置新属性，TCSANOW：所有改变立即生效
    //tcgetattr(fdcom, &termios_old);
 
    return(tmp);
}
 
/******************************************* 
 *  Open serial port 
 *  tty: 端口号 ttyS0, ttyS1, .... 
 *  返回值为串口文件描述符 
********************************************/
int PortOpen(pportinfo_t pportinfo)
{
    int  fdcom;  //串口文件描述符
    char *ptty;
 
    ptty = get_ptty(pportinfo);
    //fdcom = open(ptty, O_RDWR | O_NOCTTY | O_NONBLOCK | O_NDELAY);   
    fdcom = open(ptty, O_RDWR | O_NOCTTY | O_NONBLOCK);
 
    return (fdcom);
}
 
/******************************************* 
 *  Close serial port 
********************************************/
void PortClose(int fdcom)
{
    close(fdcom);
}
 
/******************************************** 
 *  send data 
 *  fdcom: 串口描述符，data: 待发送数据，datalen: 数据长度 
 *  返回实际发送长度 
*********************************************/
int PortSend(int fdcom, char *data, int datalen)
{
    int len = 0;
 
    len = write(fdcom, data, datalen);  //实际写入的长度   
    if(len == datalen){
        return (len);
  }
    else{
        tcflush(fdcom, TCOFLUSH);
        return -1;
    }
}
 
/******************************************* 
 *  receive data 
 *  返回实际读入的字节数 
 * 
********************************************/
int PortRecv(int fdcom, char *data, int datalen, int baudrate)
{
    int readlen, fs_sel;
    fd_set  fs_read;
    struct timeval tv_timeout;
 
    FD_ZERO(&fs_read);
    FD_SET(fdcom, &fs_read);
    tv_timeout.tv_sec  = TIMEOUT_SEC(datalen, baudrate);
    tv_timeout.tv_usec = TIMEOUT_USEC;
 
    fs_sel = select(fdcom + 1, &fs_read, NULL, NULL, &tv_timeout);
    if(fs_sel){
        readlen = read(fdcom, data, datalen);
        return(readlen);
    }
    else{
        return(-1);
    }
 
    //return (readlen);
}
 
//*************************Test*********************************   
int main(int argc, char *argv[]) {
    int fd = -1, SendLen = 0, RecvLen = 0;
    struct termios termios_cur;
    char RecvBuf[10] = {0};
    portinfo_t portinfo = {
            '0',                            // print prompt after receiving
            57600,                           // baudrate: 9600
            '8',                            // databit: 8
            '0',                            // debug: off
            '1',                            // echo: on
            '1',                            // flow control: hardware
            '0',                            // default tty: COM1
            '0',                            // parity: none
            '1',                            // stopbit: 1
             0                              // reserved
    };
 
    /*
     if(argc != 2){
         printf("Usage: <type 0 -- send 1 -- receive>\n");
         printf("   eg:");
         printf("        MyPort 0");
         exit(-1);
     }
    */
 
    fd = PortOpen(&portinfo);
    if (fd < 0) {
        printf("Error: open serial port error.\n");
        exit(1);
    }
 
    PortSet(fd, &portinfo);
    //char  *data = "hello world dhs!";
    char  data[9] = {0x11,0x22,0x33,0x11,0x22,0x33,0x11,0x22,0x88};
    //data[0] = 0xAA;
 
    int datalen = strlen(data);
    
    //send data
    //while (1)
    {
        for (int i = 0; i < 100; i++)
        {
            SendLen = PortSend(fd, data, 9);
            if (SendLen > 0) {
                printf("No %d send %d data.\n", i, SendLen);
            } else {
                printf("Error: send failed.\n");
            }
            sleep(1);
        }
    }
        PortClose(fd);
 
    /**
        for(;;)
        {
            RecvLen = PortRecv(fd, RecvBuf, 10, portinfo.baudrate);
            if(RecvLen>0){
                for(i=0; i<RecvLen; i++){
                    printf("Receive data No %d is %x.\n", i, RecvBuf[i]);
                }
                printf("Total frame length is %d.\n", RecvLen);
            }
            else{
                printf("E
                rror: receive error.\n");
            }
            sleep(2);
        }
    */
 
    return 0;
}