【发布时间】：2013-03-06 02:50:56
【问题描述】：
使用此代码，我正在尝试将文件发送到 CC430f5137 并从中接收。我正在使用 2 个程序，一个是下面的程序（它用于向我的 linux VM 发送和接收回文件，另一个是 CC430f5137 的程序（它包含我在 windows 中的设备的 rx、tx 代码）。我可以能够将单个字节（例如，A）从文件发送到我的设备，但不能发送多个字节。
//sample1.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/signal.h>
#include <sys/ioctl.h>
#include <sys/poll.h>
#include <termios.h>
#define BUFSIZE 1300 //1
int open_serial( char *dev_name, int baud, int vtime, int vmin )
{
int fd;
struct termios newtio;
fd = open( dev_name, O_RDWR | O_NOCTTY );
if ( fd < 0 )
{
printf( "Device OPEN FAIL %s\n", dev_name );
return -1;
}
memset(&newtio, 0, sizeof(newtio));
newtio.c_iflag = IGNPAR|INLCR; // non-parity void UARTHandler(int fd);
newtio.c_oflag = 0;
newtio.c_cflag = CS8 | CLOCAL | CREAD; // NO-rts/cts
switch( baud )
{
case 115200 : newtio.c_cflag |= B115200; break;
case 57600 : newtio.c_cflag |= B57600; break;
case 38400 : newtio.c_cflag |= B38400; break;
case 19200 : newtio.c_cflag |= B19200; break;
case 9600 : newtio.c_cflag |= B9600; break;
case 4800 : newtio.c_cflag |= B4800; break;
case 2400 : newtio.c_cflag |= B2400; break;
default : newtio.c_cflag |= B115200; break;
}
//set input mode (non-canonical, no echo,.....)
newtio.c_lflag = 0;
newtio.c_cc[VTIME] = vtime;
newtio.c_cc[VMIN] = vmin;
tcflush ( fd, TCIFLUSH );
tcsetattr( fd, TCSANOW, &newtio );
return fd;
}
int sendfile(int fd) //void sendfile(int fd)
{
int fd1,readc;
unsigned short fileLength;
unsigned char buf[BUFSIZE];
fd1=open("cert.pem",O_RDONLY);
fileLength=lseek(fd1,0,SEEK_END);
printf("file length is %d bytes\n",fileLength);
lseek(fd1,0,SEEK_SET);
write(fd,(unsigned char*)&fileLength, 2);
while(fileLength>0)
{
if(fileLength>=BUFSIZE)
{
readc=read(fd1,buf,BUFSIZE);
if(readc==-1)
{
printf("read failed!!\n");
}
if(read>0)
{
buf[BUFSIZE]='\0';
printf("%s\n",buf);
if(write(fd,buf,BUFSIZE))
fileLength -= BUFSIZE;
}
}
else
{
readc=read(fd1,buf,fileLength);
if(readc==-1)
{
printf("read failed!!\n");
}
if(readc>0)
{
buf[fileLength]='\0';
printf("%s\n",buf);
if(write(fd, buf, fileLength))
fileLength=0;
}
}
}
printf("%s\n",fd);
printf("file sent succssfully\n");
return fd1;//close(fd1);
close(fd);
}
void receivefile(int fd)
{
char buf[1300],read_byte,buf2[1300];
int fd2,readc;
unsigned short fileLength;
fd2=open("test.pem", O_WRONLY|O_CREAT);
if(fd2<0)
{
printf("file open failed!!\n");
}
while(!(read(fd,(unsigned char*)&fileLength,2)>0));
printf("i am in receive file\n");
while(fileLength>0)
{
readc = read(fd, buf, BUFSIZE);
if(readc==-1)
{
printf("read failed!!\n");
}
printf("read %d bytes, value is %s\n",readc,buf);
if(readc >0)
{
buf[readc]='\0';
printf("buf value is%s\n", buf);
write(fd2,buf,readc);
fileLength -= readc;
}
}
close(fd2);
close(fd);
}
void close_serial( int fd )
{
close( fd );
printf("ClosePort!!\n");
}
int main( int argc, char **argv )
{
int fd;
int baud;
char dev_name[128];
if ( argc != 3)
{
printf( " sample_serial [device] [baud]\n" \
" device : /dev/ttySAC0 ...\n" \
" baud : 2400 ... 115200\n" );
return -1;
}
printf( " Serial test start... (%s)\n", __DATE__ );
strcpy( dev_name, argv[1] );
baud = strtoul( argv[2], NULL, 10 );
fd = open_serial( dev_name, baud, 4, 1);
sendfile(fd);
receivefile(fd);
close_serial( fd );
printf( " Serial test end\n" );
return 0;
}
这是从文件发送 1 个字节到串口的输出
[root@localhost ~]# gcc -std=c99 -std=gnu99 sample1.c -o out1
sample1.c:151:50: warning: backslash and newline separated by space
sample1.c:152:45: warning: backslash and newline separated by space
[root@localhost ~]# ./out1 /dev/ttyUSB20 115200
Serial test start... (Mar 6 2013)
file length is 2 bytes
A
wrote 3 bytes
file sent succssfully
i am in receive file
read 1 bytes, value is A
buf value isA
read 1 bytes, value is A
buf value isA
read 1 bytes, value is A
buf value isA
read 1 bytes, value is A
buf value isA
这是从文件向串口发送多个字节的输出
[root@localhost ~]# gcc -std=c99 -std=gnu99 sample1.c -o out1
sample1.c:151:50: warning: backslash and newline separated by space
sample1.c:152:45: warning: backslash and newline separated by space
[root@localhost ~]# ./out1 /dev/ttyUSB20 115200
Serial test start... (Mar 6 2013)
file length is 2 bytes
i am doing well today
wrote 3 bytes
file sent succssfully
i am in receive file
read 1 bytes, value is
buf value is
read 1 bytes, value is
buf value is
read 1 bytes, value is
buf value is
read 1 bytes, value is
buf value is
正如你在这里看到的，我没有得到文件内容，我正在接收空字符 从我的设备，即使我向我的设备发送了多个字节。
sendfile() 工作正常，我可以将“cert.pem”写入端口。我有一个 从端口读取文件并写回“test.pem”的问题。我得到了输出 接收程序中给出了一些打印语句，但连续获取数据。标志设置在 正确的方式。我也重置了所有连接。
【问题讨论】：
-
有很多代码供我们阅读……您能否更具体地说明哪些有效，哪些无效？也许只显示代码的相关部分？
-
串行端口可能是毛茸茸的小野兽。您发布代码并要求我们告诉您为什么“它不起作用”对您来说没有效率。您应该首先自己进行一些基本调查。获取连接代码并测试它是否有效。检查所有端口标志是否设置正确。尝试发送和接收单个字节。测试您的文件是否被正确打开和读取。测试接收端是否可以创建文件。
-
在上面的注释中......我注意到当你打开
test.pem时你从不检查你的文件句柄是否有效。 -
while(!(read(fd,(unsigned char*)&fileLength,2)>0));的目的是什么？这实际上并没有给你带来任何好处，如果 read 返回-1（错误），它实际上会伤害你——你会永远循环。 man read -
libcurl ??? curl.haxx.se/libcurl
标签： c linux file-io serial-port