树莓派串口读取陀螺仪ky9250(mpu9250)数据

9轴姿态角度传感器，其中ky9250陀螺仪由于自带卡尔曼动态滤波算法方便用户使用。ky9250陀螺仪基本可以在各个平台上进行数据的读取（如stm32\arduino\C#\Matlab\树莓\Unity3d\python\ROS\英飞凌\Nvidia jetson linux 等）

1、树莓派和ky9250的接线方式

树莓派和ky92509250的模块（VCC对3V3,RX对TX，TX对RX，GND对GND）

2、安装树莓ch340驱动（下载包中有）

3、上传电脑的示例代码文件到树莓派中

#include<stdio.h>
#include<stdlib.h>
#include<fcntl.h>
#include<unistd.h>
#include<assert.h>
#include<termios.h>
#include<string.h>
#include<sys/time.h>
#include<time.h>
#include<sys/types.h>
#include<errno.h>

static int ret;
static int fd;

#define BAUD 115200 //115200

int uart_open(int fd,const char *pathname)
{
    fd = open(pathname, O_RDWR|O_NOCTTY); 
    if (-1 == fd)
    { 
        perror("Can't Open Serial Port"); 
		return(-1); 
	} 
    else
		printf("open %s success!\n",pathname);
    if(isatty(STDIN_FILENO)==0) 
		printf("standard input is not a terminal device\n"); 
    else 
		printf("isatty success!\n"); 
    return fd; 
}

int uart_set(int fd,int nSpeed, int nBits, char nEvent, int nStop)
{
     struct termios newtio,oldtio; 
     if  ( tcgetattr( fd,&oldtio)  !=  0) {  
      perror("SetupSerial 1");
	  printf("tcgetattr( fd,&oldtio) -> %d\n",tcgetattr( fd,&oldtio)); 
      return -1; 
     } 
     bzero( &newtio, sizeof( newtio ) ); 
     newtio.c_cflag  |=  CLOCAL | CREAD;  
     newtio.c_cflag &= ~CSIZE;  
     
     switch( nBits ) 
     { 
     case 7: 
      newtio.c_cflag |= CS7; 
      break; 
     case 8: 
      newtio.c_cflag |= CS8; 
      break; 
     } 
     switch( nEvent ) 
     { 
     case 'o':
     case 'O': 
      newtio.c_cflag |= PARENB; 
      newtio.c_cflag |= PARODD; 
      newtio.c_iflag |= (INPCK | ISTRIP); 
      break; 
     case 'e':
     case 'E': 
      newtio.c_iflag |= (INPCK | ISTRIP); 
      newtio.c_cflag |= PARENB; 
      newtio.c_cflag &= ~PARODD; 
      break;
     case 'n':
     case 'N': 
      newtio.c_cflag &= ~PARENB; 
      break;
     default:
      break;
     } 

     /*设置波特率*/ 

switch( nSpeed ) 
     { 
     case 2400: 
      cfsetispeed(&newtio, B2400); 
      cfsetospeed(&newtio, B2400); 
      break; 
     case 4800: 
      cfsetispeed(&newtio, B4800); 
      cfsetospeed(&newtio, B4800); 
      break; 
     case 9600: 
      cfsetispeed(&newtio, B9600); 
      cfsetospeed(&newtio, B9600); 
      break; 
     case 115200: 
      cfsetispeed(&newtio, B115200); 
      cfsetospeed(&newtio, B115200); 
      break; 
     case 460800: 
      cfsetispeed(&newtio, B460800); 
      cfsetospeed(&newtio, B460800); 
      break; 
     default: 
      cfsetispeed(&newtio, B9600); 
      cfsetospeed(&newtio, B9600); 
     break; 
     } 
     if( nStop == 1 ) 
      newtio.c_cflag &=  ~CSTOPB; 
     else if ( nStop == 2 ) 
      newtio.c_cflag |=  CSTOPB; 
     newtio.c_cc[VTIME]  = 0; 
     newtio.c_cc[VMIN] = 0; 
     tcflush(fd,TCIFLUSH); 

if((tcsetattr(fd,TCSANOW,&newtio))!=0) 
     { 
      perror("com set error"); 
      return -1; 
     } 
     printf("set done!\n"); 
     return 0; 
}

int uart_close(int fd)
{
    assert(fd);
    close(fd);

    return 0;
}
int send_data(int  fd, char *send_buffer,int length)
{
	length=write(fd,send_buffer,length*sizeof(unsigned char));
	return length;
}
int recv_data(int fd, char* recv_buffer,int length)
{
	length=read(fd,recv_buffer,length);
	return length;
}

float a[17];

void ParseData(char chr)
{
    static char chrBuf[100];
    static unsigned char chrCnt=0;
    static char sData[100];
    unsigned char i;
    
    time_t now;
    chrBuf[chrCnt++]=chr;
    if (chrCnt<52) return;
    
    if (( (chrBuf[0]&0x50)!=0x50 ))
    {
       printf("Error:%x %x\r\n",chrBuf[0],chrBuf[1]);
       memcpy(&chrBuf[0],&chrBuf[1],51);chrCnt--;
       return;
   }
    
    memcpy(&sData[0],&chrBuf[0],52);
		switch(chrBuf[0])
		{
				case 0x50:
					 if ((sData[49] * 256.0 * 256.0 + sData[50] * 256.0 + sData[51] - 1000000) * 0.001==128)     //校验
					{
                                                                                 a[0] = (sData[1] * 256.0 * 256.0 + sData[2] * 256.0 + sData[3] - 1000000) * 0.001;    //gx   开始解析串口数据
                				 a[1] = (sData[4] * 256.0 * 256.0 + sData[5] * 256.0 + sData[6] - 1000000) * 0.001;
               					 a[2] = (sData[7] * 256.0 * 256.0 + sData[8] * 256.0 + sData[9] - 1000000) * 0.001;
                                                                                 
                                                                                 a[3] = (sData[10] * 256.0 * 256.0 + sData[11] * 256.0 + sData[12] - 1000000) * 0.001;  //ax
                 	                                                 a[4] = (sData[13] * 256.0 * 256.0 + sData[14] * 256.0 + sData[15] - 1000000) * 0.001;
                 				 a[5] = (sData[16] * 256.0 * 256.0 + sData[17] * 256.0 + sData[18] - 1000000) * 0.001;

				                 a[6] = (sData[19] * 256.0 * 256.0 + sData[20] * 256.0 + sData[21] - 1000000) * 0.001; //mx
                 				 a[7] = (sData[22] * 256.0 * 256.0 + sData[23] * 256.0 + sData[24] - 1000000) * 0.001;
                 				 a[8] = (sData[25] * 256.0 * 256.0 + sData[26] * 256.0 + sData[27] - 1000000) * 0.001;

                 				a[9]  = (sData[28] * 256.0 * 256.0 + sData[29] * 256.0 + sData[30] - 1000000) * 0.001; //roll
                 				a[10] = (sData[31] * 256.0 * 256.0 + sData[32] * 256.0 + sData[33] - 1000000) * 0.001; //pitch
                 				a[11] = (sData[34] * 256.0 * 256.0 + sData[35] * 256.0 + sData[36] - 1000000) * 0.001;  //raw

                 				a[12] = (sData[37] * 256.0 * 256.0 + sData[38] * 256.0 + sData[39] - 1000000) * 0.001;   //q0
                 				a[13] = (sData[40] * 256.0 * 256.0 + sData[41] * 256.0 + sData[42] - 1000000) * 0.001;  //q1
                 				a[14] = (sData[43] * 256.0 * 256.0 + sData[44] * 256.0 + sData[45] - 1000000) * 0.001;  //q2
                 				a[15] = (sData[46] * 256.0 * 256.0 + sData[47] * 256.0 + sData[48] - 1000000) * 0.001;  //q3 
                                                                                }  

                                                                                time(&now);
					printf("\r\nT:%s a:%6.3f %6.3f %6.3f ",asctime(localtime(&now)),a[0],a[1],a[2]);  //输出加速度   可以自己照这行增加其他数据输出
                                                                                 
                                                                                printf("\r\nT:%s a:%6.3f %6.3f %6.3f ",asctime(localtime(&now)),a[9],a[10],a[11]);  //输出欧拉角
					
					break;
				
		}		
		chrCnt=0;		
}

int main(void)
{
    char r_buf[1024];
    bzero(r_buf,1024);

    fd = uart_open(fd,"/dev/ttyUSB0");/*串口号/dev/ttySn,USB口号/dev/ttyUSBn */ 
    if(fd == -1)
    {
        fprintf(stderr,"uart_open error\n");
        exit(EXIT_FAILURE);
    }

    if(uart_set(fd,BAUD,8,'N',1) == -1)
    {
        fprintf(stderr,"uart set failed!\n");
        exit(EXIT_FAILURE);
    }

	FILE *fp;
	fp = fopen("Record.txt","w");
    while(1)
    {
        ret = recv_data(fd,r_buf,44);
        if(ret == -1)
        {
            fprintf(stderr,"uart read failed!\n");
            exit(EXIT_FAILURE);
        }
		for (int i=0;i<ret;i++) {fprintf(fp,"%2X ",r_buf[i]);ParseData(r_buf[i]);}
        usleep(1000);
    }

    ret = uart_close(fd);
    if(ret == -1)
    {
        fprintf(stderr,"uart_close error\n");
        exit(EXIT_FAILURE);
    }

    exit(EXIT_SUCCESS);
}

4、即可在树莓中取得陀螺仪数据

终端中的Desktop文件夹即为桌面

编辑：gcc Uart901Demo.cpp -o Uart901Demo

运行：./ Uart901Demo