淮安做微信网站,网站可以做315认证吗,免费店铺logo在线制作,wordpress后台界面更改一、前言
上一篇博文记录了使用wiringPi提供的串口驱动wiringSerial.c wiringSerial.h#xff0c;并基于该驱动对串口进行简单的通信#xff0c;测试中发现该串口的驱动比较简单#xff0c;接收数据会存在分包的现象#xff0c;另外一点是串口配置只提供了波特率参数配置并基于该驱动对串口进行简单的通信测试中发现该串口的驱动比较简单接收数据会存在分包的现象另外一点是串口配置只提供了波特率参数配置未提供其他如校验、数据位和停止位驱动。这一片博文主要是对驱动进行修改。
二、修改驱动
wiringPi的驱动源码可以在https://projects.drogon.net/raspberry-pi/wiringpi/中下载。找到wiringSerial.c 和 wiringSerial.h两个文件复制一份并重名命为wiringSerial_Driver.c wiringSerial_Driver.h。以便于我们修改。
具体地修改包括初始化函数、串口接收函数和串口发送函数。
2.1 初始化函数修改
可以同时初始化波特率、停止位、校验位和数据位。参数gsfd为全局定义的串口打开设备ID号static int gsfd;
linux串口编程主要是对termios进行初始化需要包含头文件#include termios.h
在Rpi3B中输入
man termios
可以查看termios的描述具体不多讲看说明文档即可以下仅罗列部分 NAMEtermios, tcgetattr, tcsetattr, tcsendbreak, tcdrain, tcflush, tcflow, cfmakeraw, cfgetospeed, cfgetispeed, cfsetispeed, cfsetospeed, cfsetspeed - getand set terminal attributes, line control, get and set baud rateSYNOPSIS#include termios.h#include unistd.hint tcgetattr(int fd, struct termios *termios_p);int tcsetattr(int fd, int optional_actions,const struct termios *termios_p);int tcsendbreak(int fd, int duration);int tcdrain(int fd);int tcflush(int fd, int queue_selector);int tcflow(int fd, int action);void cfmakeraw(struct termios *termios_p);speed_t cfgetispeed(const struct termios *termios_p);speed_t cfgetospeed(const struct termios *termios_p);int cfsetispeed(struct termios *termios_p, speed_t speed);int cfsetospeed(struct termios *termios_p, speed_t speed);int cfsetspeed(struct termios *termios_p, speed_t speed);Feature Test Macro Requirements for glibc (see feature_test_macros(7)):cfsetspeed(), cfmakeraw(): _BSD_SOURCEDESCRIPTIONThe termios functions describe a general terminal interface that is provided to control asynchronous communications ports.The termios structureMany of the functions described here have a termios_p argument that is a pointer to a termios structure. This structure contains at least the follow‐ing members:tcflag_t c_iflag; /* input modes */tcflag_t c_oflag; /* output modes */tcflag_t c_cflag; /* control modes */tcflag_t c_lflag; /* local modes */cc_t c_cc[NCCS]; /* special characters */The values that may be assigned to these fields are described below. In the case of the first four bit-mask fields, the definitions of some of theassociated flags that may be set are exposed only if a specific feature test macro (see feature_test_macros(7)) is defined, as noted in brackets([]).In the descriptions below, not in POSIX means that the value is not specified in POSIX.1-2001, and XSI means that the value is specified inPOSIX.1-2001 as part of the XSI extension.
那么具体的驱动可以改写成一下内容
int myserialOpen (const char *device, const int baud, const int nbit, const char parity, const int nstop)
{struct termios options ;speed_t myBaud ;int status;switch (baud){case 50: myBaud B50 ; break ;case 75: myBaud B75 ; break ;case 110: myBaud B110 ; break ;case 134: myBaud B134 ; break ;case 150: myBaud B150 ; break ;case 200: myBaud B200 ; break ;case 300: myBaud B300 ; break ;case 600: myBaud B600 ; break ;case 1200: myBaud B1200 ; break ;case 1800: myBaud B1800 ; break ;case 2400: myBaud B2400 ; break ;case 4800: myBaud B4800 ; break ;case 9600: myBaud B9600 ; break ;case 19200: myBaud B19200 ; break ;case 38400: myBaud B38400 ; break ;case 57600: myBaud B57600 ; break ;case 115200: myBaud B115200 ; break ;case 230400: myBaud B230400 ; break ;case 460800: myBaud B460800 ; break ;case 500000: myBaud B500000 ; break ;case 576000: myBaud B576000 ; break ;case 921600: myBaud B921600 ; break ;case 1000000: myBaud B1000000 ; break ;case 1152000: myBaud B1152000 ; break ;case 1500000: myBaud B1500000 ; break ;case 2000000: myBaud B2000000 ; break ;case 2500000: myBaud B2500000 ; break ;case 3000000: myBaud B3000000 ; break ;case 3500000: myBaud B3500000 ; break ;case 4000000: myBaud B4000000 ; break ;default:return -2 ;}/* 有O_NONBLOCK 即为非阻塞方式默认阻塞方式等待vim vtime*/if ((gsfd open (device, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK)) -1)return -1 ;fcntl (gsfd, F_SETFL, O_RDWR) ;// Get and modify current options:tcgetattr (gsfd, options) ;cfmakeraw (options) ;cfsetispeed (options, myBaud) ;cfsetospeed (options, myBaud) ;//data bitswitch (nbit){case 7: options.c_cflag ~CSIZE ; options.c_cflag | CS7; break;case 8: options.c_cflag ~CSIZE ; options.c_cflag | CS8; break;default: options.c_cflag ~CSIZE ; options.c_cflag | CS8; break;}//data parityswitch(parity) {case n:case N:options.c_cflag ~PARENB ;options.c_cflag ~INPCK;break;case o:case O: options.c_cflag | PARENB ;options.c_cflag | PARODD ;options.c_cflag | INPCK ;options.c_cflag | ISTRIP ; break;case e:case E: options.c_cflag | PARENB ;options.c_cflag ~PARODD;options.c_cflag | INPCK ;options.c_cflag | ISTRIP ;break;default:options.c_cflag ~PARENB ;options.c_cflag ~INPCK;break;}//data stopbitsswitch(nstop){case 1: options.c_cflag ~CSTOPB ; break;case 2: options.c_cflag | CSTOPB ; break; default: options.c_cflag ~CSTOPB ; break; }options.c_cflag | (CLOCAL | CREAD) ;options.c_lflag ~(ICANON | ECHO | ECHOE | ISIG) ;options.c_oflag ~OPOST ;options.c_cc [VMIN] 0 ;options.c_cc [VTIME] 10 ; // 0.5 seconds (100 deciseconds)tcsetattr (gsfd, TCSANOW, options) ;ioctl (gsfd, TIOCMGET, status);status | TIOCM_DTR ;status | TIOCM_RTS ;ioctl (gsfd, TIOCMSET, status);usleep (10000) ; // 10mSreturn gsfd ;
}2.2 接收函数修改
提一下Linux串口接收主要由阻塞和非阻塞接收两种方式关于如何配置Linux串口驱动可以参考这篇博文Linux 使用fcntl c_cc[VMIN] c_cc[CTIME]设置串口阻塞与非阻塞读取数据
实际测试时发现wiringSerial的接收函数serialDataAvail缓存大小只有8字符因此超过8字符的数据将会分包接收函数修改主要是对数据进行拼包具体实现如下
int myserialDataRead( char *buf, int * size)
{int size_i,i;i 0;size_i 0;while(1){i read(gsfd, bufsize_i ,1024);size_i i;if(i 8){}else if(i0 i 8){*size size_i;return 0;}else{return -1;}}
}
2.3 发送函数修改
发送函数基本和wiringSerial提供的驱动一致只是将传入的设备ID用全局变量替代这样在使用该函数时无需输入串口的ID。具体修改如下
void myserialDataSend(const char * ptr,int size)
{while(size--){serialPutchar(gsfd,*(ptr));}
}
三、编译测试
对应的头文件增加函数的声明编写main.c测试文件
#includewiringPi.h
#includewiringSerial_Driver.h
#includestdio.h
#includestring.hint main()
{int filedevid;int recbytenum;int rxflag;int i;char buf[1024];char bufprintf[1024];memset(buf,0,1024);memset(bufprintf,0,1024);wiringPiSetup();if((filedevidmyserialOpen(/dev/ttyAMA0,115200,8,E,1))0){printf(/dev/ttyAMA0 Open Faild\r\n);return -1;}else{printf(/dev/ttyAMA0 Open with 115200,115200,8,E,1, success\r\n);while(1){rxflag myserialDataRead(buf,recbytenum);if(rxflag ! -1){printf(Rpi3 uart rx %d byte: %s\r\n,recbytenum,buf);sprintf(bufprintf,Rpi3 uart Tx %d byte: %s\r\n,recbytenum,buf);myserialDataSend(bufprintf, recbytenum);}}}
}
编写makefile进行编译并运行如下 可以看到数据以及拼包成功说明驱动修改有效。
