我一直在尝试通过 RS232 串行端口(在我的情况下是 COM6)与我的设备通信。我的代码应该向设备写入一串 ascii 值,然后读取响应,但是我似乎无法得到任何响应。当我让它在我的计算机中写入和读取文件时,该程序似乎工作得相对较好,但当我指定 COM6 时则不然。这是我的代码的最新版本:
using namespace std;
const char ASCII[ ]= "0123456789ABCDEF";
char *Checksum (char *buffer)
{
static char Hex[10];
static int a1, a2;
register unsigned int i;
int sum;
printf("%s \n", buffer);
sum = 256;
for ( i=0 ; i<strlen(buffer) ; i++ )
{
sum-=buffer[i];
if ( sum<0 )
sum+= 256;
}
a1 = (sum & 0xF0) >> 4;
a2 = sum & 0x0F;
Hex[0] = ASCII[a1];
Hex[1] = ASCII[a2];
Hex[2] = 0;
printf("the checksum is %s \n",Hex);
return(Hex);
}
int main()
{
char data[80], input[80], *data2;
char *response;
DCB dcb;
bool retVal;
DWORD dwBytesTransferred;
DWORD byteswritten;
printf("the variable response is initially: %d\n", response);
dcb.BaudRate = CBR_19200; //19200 Baud
dcb.ByteSize = 8; //8 data bits
dcb.Parity = NOPARITY; //no parity
dcb.StopBits = ONESTOPBIT; //1 stop
//New open port area
HANDLE hPort;
if ((hPort = CreateFile ( "\\\\.\\COM6",
GENERIC_READ | GENERIC_WRITE,
0, // exclusive access
NULL, // no security attrs
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL)) != INVALID_HANDLE_VALUE)
{
printf("SUCCESS opening the port\n");// success
}
//GetCommState
DCB Dcb;
GetCommState (hPort, &Dcb);
Dcb.BaudRate = CBR_19200;
Dcb.StopBits = ONESTOPBIT;
Dcb.ByteSize = 8;
Dcb.Parity = NOPARITY;
Dcb.fParity = 0;
Dcb.fOutxCtsFlow = 0;
Dcb.fOutxDsrFlow = 0;
Dcb.fDsrSensitivity = 0;
Dcb.fTXContinueOnXoff = TRUE;
Dcb.fOutX = 0;
Dcb.fInX = 0;
Dcb.fNull = 0;
Dcb.fErrorChar = 0;
Dcb.fAbortOnError = 0;
Dcb.fRtsControl = RTS_CONTROL_DISABLE;
Dcb.fDtrControl = DTR_CONTROL_DISABLE;
//Flushing
FlushFileBuffers( hPort );
PurgeComm (hPort, PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR);
COMSTAT comStat;
DWORD dwErrorFlags;
ClearCommError ( hPort, &dwErrorFlags, &comStat );
//NEW commtimeouts area
COMMTIMEOUTS CommTimeOuts;
DWORD dwTimeout = 3000; // <- set timeout in milliseconds
if(!dwTimeout)
{ // Don't use timeout -> Read the bytes already in input buffer and return immediately
CommTimeOuts.ReadIntervalTimeout = MAXDWORD;
CommTimeOuts.ReadTotalTimeoutConstant = 0;
} else
{ // Use given timeout, wait until the requested number of bytes are read - or timeout
CommTimeOuts.ReadIntervalTimeout = 0;
CommTimeOuts.ReadTotalTimeoutConstant = dwTimeout;
}
CommTimeOuts.ReadTotalTimeoutMultiplier = 0;
CommTimeOuts.WriteTotalTimeoutMultiplier = 0;
CommTimeOuts.WriteTotalTimeoutConstant = 0;
SetCommTimeouts (hPort, &CommTimeOuts);
printf("insert ASCII code string you wish to send:");
scanf("%s", input);
strcpy(data, "{0x02}");
strcat(data, input);
printf("%s \n", data);
data2=Checksum(data);
strcat(data, data2);
strcat(data, "{0x03}");
printf("the final sent message will be: %s \n",data);
retVal = WriteFile(hPort,data, strlen(data), &byteswritten, NULL);
printf("Number of bytes written: %d\n", byteswritten);
printf("Write Success? %d\n", retVal);
retVal=ReadFile (hPort, &response, 20, &dwBytesTransferred, NULL);
printf("Read Success? %d\n", retVal);
printf("Port Response: %d\n", response);
free(response);
return 0;
}
最新发现总结:使用 Habi 建议的 Free Serial Port Monitor 我现在可以确定 WriteFile 工作正常,并且 COM6 正在接收消息。我仍在寻找交叉电缆来仔细检查消息是否正在通过线路传输。我想,当我试图弄清楚是否有人可以查看这个新版本并告诉我是否有任何问题时,特别是与 ReadFile 函数有关的问题,我将不胜感激。困扰我的是,免费串行端口软件只显示从我的计算机传递的数据,而根本没有来自设备的响应。=\