串口读取数据只能一次读取17个字节，写可以写256

2017-11-07 05:18:37 754 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

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Modbus---＞使用ModbusPoll、ModbusSlave、虚拟串口分析MODBUS-RTU数据帧格式、报文实例帧结构，和Modbus协议格式文章目录使用Modbus poll&Modbus slave模拟Modbus主从通信虚拟串口基础知识积累MODBUS-RTU报文模型主机对从机写数据操作主机对从机写数据操作后，从机的返回内容主机对从机读数据操作主机对从机读数据操作后，从机对主机返回内容Modbus-RTU常用功能码寄存器起始地址（起始数据地址）使用Modbus poll&Modbus slave模拟Modbus主从通信下载和破解搜一下都很方便，使用的时候Modbus Poll作为Master，Modbus slave作阅读详情

int OpenDev(char *Dev)
{
speed_t speed;
int i=0;
int fdt,c=0,num;
struct termios oldtio,newtio;
speed = getBaudrate(115200);
fdt=open(Dev,O_RDWR | O_NONBLOCK| O_NOCTTY | O_NDELAY);
if(fdt<0)
{
perror(Dev);
exit(1);
}
//save to oldtio
tcgetattr(fdt,&newtio);
//clear newtio
bzero(&newtio,sizeof(newtio));
// newtio.c_cflag = speed|CS8|CLOCAL|CREAD|CRTSCTS;
//newtio.c_cflag&=~CSIZE;
oldtio.c_cflag |=CS8;
newtio.c_cflag = speed|CS8|CLOCAL|CREAD;
newtio.c_iflag = IGNPAR;
//newtio.c_oflag &=~OPOST;
newtio.c_oflag &=~OPOST;
// newtio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
/*Input*/
//printf("newtio.c_cflag=%x\n",newtio.c_cflag);
tcflush(fdt,TCIFLUSH);
tcsetattr(fdt,TCSANOW,&newtio);
// tcgetattr(fdt,&oldtio);
//printf("oldtio.c_cflag=%x\n",oldtio.c_cflag);
return fdt;
}

void read_port(void)
{

char dev_id[32];
int kj_id,ret;
FD_ZERO(&rd);
FD_SET(fd,&rd);
timeout.tv_sec = 1;
timeout.tv_usec = 500;
char read_tmp[256];
int i;
retval = select (fd+1,&rd,NULL,NULL,&timeout);
char fbuf[256];
switch (retval)
{
case 0:
printf("no data input within 1s.\n");
break;
case -1:
perror("select");
break;
default:
memset(fbuf,0,sizeof(fbuf));

if((nread=read(fd,read_tmp,256))>0)
{

printf("%d\n",nread);
printf("read1:%s\n",read_tmp);
}

// tcflush(fd,TCIOFLUSH);
SERIAL_DATA_SET getSerialData;
printf("nlen :%d\n",nread);
// read_tmp[nread+1]="\0";
// read_tmp[256]="\0";
printf("%s\n",fbuf);
char buf[512];
printf("%s\n",read_tmp);
memset(&getSerialData, 0, sizeof( SERIAL_DATA_SET));
xml2s_get_serial_req((const char *)fbuf, &getSerialData);
//ret=memcpy(judgmentbuf,read_tmp[0],1);
char xmlData[512];
printf("Resurt:%d\n",getSerialData.Resurt);
printf("DevID:%s\n",getSerialData.DevID);
printf("SNnum:%s\n",getSerialData.SNnum);
memset(xmlData,0,sizeof(xmlData));
sprintf(xmlData,
"<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n"
"<GET_SERIAL_RECORDS_RES>\n"
" <Resurt>%d</Resurt>\n"
" <DevID>%s</DevID>\n"
" <SNnum>%s</SNnum>\n",
getSerialData.Resurt,
getSerialData.DevID,
getSerialData.SNnum
);
printf("%s\n",xmlData);
if(ret<0)
{
perror("judgmentbuf");

}
printf("11\n");

if(getSerialData.Resurt==1)
{
memcpy(buf,read_tmp+1,9);
printf("888\n");
//kj_id= atoi(buf);

ret=set_config_param_str("/mnt/nand/cms.cfg","DevID",buf);
if(ret<0)
{
printf("set DevID error\n");
}

ret=get_config_param_str("/mnt/nand/cms.cfg","DevID",dev_id,32);
if(!strcmp(buf,dev_id))
{
int ii;
char serialRepaly[512];
sprintf(serialRepaly,
"<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n"
"<GET_SERIAL_RECORDS_RPY>\n"
" <Resurt>%d</Resurt>\n"
" <DevID>%s</DevID>\n"
" <SNnum>%s</SNnum>\n",
1,
getSerialData.DevID,
getSerialData.SNnum
);
ii=write(fd,serialRepaly,sizeof(sendpack));
printf("%s\n",serialRepaly);
if(ii==sizeof(sendpack))
{}
else
{
printf("send error \n");}
//
if(sendnum<65535)
{
sendnum++;
}
else
{
sendnum_times++;
sendnum=1;
}
}
}
msleep(500);

fflush(stdin);

#if 0
if(recenum<65535)
{
recenum++;
}
else
{
recenum_times++;
recenum=1;
}
#endif

}
}

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