C / C++ / MFC

31-Mar-10 3:59

Unfortunately, I have a project where I need to use the serial port to communicate with an older device on our shop floor. I have a SERIALIO class that used to work with VC 6, but now when I try to use it with VS 2K5 it does not seem to work anymore and I cannot figure out why. I am assuming that the issue is with how the port is being initialized, because the device is not always getting a signal. I can determine this by watching the communications LED on the device itself.

Essentially, the process is to
1. Initialize the port
2. Send data string to device (*ID-)
3. get response from device (coded in a timeout function so that if the process takes more than 5S, will return TIMEOUT string)
4. Process the return string

What is happening is that device is either returning "ER" or the function will return "TIMEOUT". The "ER" means that the device does recognize the command sent.

When I use Hyper-Terminal and set the properties to 4800, n,8,1,Flow Control to use XON/XOFF, I get response every time. But, the following code fails and I am lost. Can anyone help?
(Sorry for the lengthy code to follow)
Here is my configuration script to initialize the serial port:

<br />
SerialIO::SerialIO(	LPCWSTR port,<br />
					long baud,<br />
					LPCSTR parity,<br />
					long data,<br />
					long stop){<br />
	USES_CONVERSION;<br />
	char initstr[256];<br />
	char errmsg[256];<br />
	COMMTIMEOUTS timeouts;<br />
	bf="";<br />
	buffer[0]='\0';<br />
	DCB dcb={0};<br />
	<br />
	<br />
	sprintf_s(initstr,"baud=%ld parity=%s data=%ld stop=%ld",<br />
			baud,parity,data,stop);<br />
	idCommDev=CreateFileW(	port,<br />
							GENERIC_READ|GENERIC_WRITE,<br />
							0,<br />
							NULL,<br />
							OPEN_EXISTING,<br />
							0,<br />
							NULL);<br />
	<br />
	if(idCommDev!=INVALID_HANDLE_VALUE)	{<br />
		if(baud){<br />
			//  Initialize the DCB structure.<br />
			SecureZeroMemory(&dcb, sizeof(DCB));<br />
			dcb.DCBlength = sizeof(DCB);<br />
			//fsuccess = GetCommState(idCommDev, &dcb);<br />
			if(GetCommState(idCommDev, &dcb))<br />
			{<br />
				//  Fill in some DCB values and set the com state: <br />
				//  4800 bps, 8 data bits, no parity, and 1 stop bit.<br />
				dcb.BaudRate = CBR_4800;     //  baud rate<br />
				dcb.ByteSize = 8;             //  data size, xmit and rcv<br />
				dcb.Parity   = NOPARITY;      //  parity bit<br />
				dcb.StopBits = ONESTOPBIT;    //  stop bit<br />
				dcb.fInX=FALSE;<br />
				dcb.fOutX=FALSE;	<br />
				dcb.fOutxCtsFlow=FALSE;		<br />
				dcb.fRtsControl=RTS_CONTROL_DISABLE;<br />
				dcb.fOutxDsrFlow=FALSE;<br />
				if(!SetCommState(idCommDev, &dcb))<br />
				{<br />
					CString lpMsgBuf;<br />
					char lpDisplayBuf[512];<br />
					DWORD dw = GetLastError(); <br />
					FormatMessage(<br />
						FORMAT_MESSAGE_ALLOCATE_BUFFER | <br />
						FORMAT_MESSAGE_FROM_SYSTEM |<br />
						FORMAT_MESSAGE_IGNORE_INSERTS,<br />
						NULL,<br />
						dw,<br />
						MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),<br />
						(LPTSTR) &lpMsgBuf,<br />
						0, NULL );<br />
					sprintf_s(lpDisplayBuf, "SetCommState failed with error:\r\n(%d): %s",dw,W2A(lpMsgBuf));<br />
					MessageBoxW(NULL, A2W(lpDisplayBuf), L"Error", MB_OK); <br />
				}<br />
				if(!GetCommState(idCommDev, &dcb))<br />
				{<br />
					CString lpMsgBuf;<br />
					char lpDisplayBuf[512];<br />
					DWORD dw = GetLastError(); <br />
					FormatMessage(<br />
						FORMAT_MESSAGE_ALLOCATE_BUFFER | <br />
						FORMAT_MESSAGE_FROM_SYSTEM |<br />
						FORMAT_MESSAGE_IGNORE_INSERTS,<br />
						NULL,<br />
						dw,<br />
						MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),<br />
						(LPTSTR) &lpMsgBuf,<br />
						0, NULL );<br />
					sprintf_s(lpDisplayBuf, "GetCommState after SetCommState with error:\r\n(%d): %s",dw,W2A(lpMsgBuf));<br />
					MessageBoxW(NULL, A2W(lpDisplayBuf), L"Error", MB_OK); <br />
				}<br />
			}<br />
			else<br />
		    {<br />
				CString lpMsgBuf;<br />
				char lpDisplayBuf[512];<br />
				DWORD dw = GetLastError(); <br />
				FormatMessage(<br />
					FORMAT_MESSAGE_ALLOCATE_BUFFER | <br />
					FORMAT_MESSAGE_FROM_SYSTEM |<br />
					FORMAT_MESSAGE_IGNORE_INSERTS,<br />
					NULL,<br />
					dw,<br />
					MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),<br />
					(LPTSTR) &lpMsgBuf,<br />
					0, NULL );<br />
				sprintf_s(lpDisplayBuf, "GetCommState (Initial) failed with error:\r\n (%d): %s",dw,W2A(lpMsgBuf));<br />
				MessageBoxW(NULL, A2W(lpDisplayBuf), L"Error", MB_OK); <br />
			}<br />
		}<br />
<br />
		SetupComm(idCommDev,(DWORD)1600,(DWORD)1600);<br />
		timeouts.ReadIntervalTimeout=MAXDWORD;<br />
		timeouts.ReadTotalTimeoutMultiplier=MAXDWORD;<br />
		timeouts.ReadTotalTimeoutConstant=10000;<br />
		timeouts.WriteTotalTimeoutMultiplier=0;<br />
		timeouts.ReadTotalTimeoutConstant=0;<br />
		SetCommTimeouts(idCommDev,&timeouts);<br />
		ReadMutex=NULL;<br />
	}<br />
	else {<br />
		CString lpMsgBuf;<br />
		char lpDisplayBuf[512];<br />
		DWORD dw = GetLastError(); <br />
		FormatMessage(<br />
			FORMAT_MESSAGE_ALLOCATE_BUFFER | <br />
			FORMAT_MESSAGE_FROM_SYSTEM |<br />
			FORMAT_MESSAGE_IGNORE_INSERTS,<br />
			NULL,<br />
			dw,<br />
			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),<br />
			(LPTSTR) &lpMsgBuf,<br />
			0, NULL );<br />
		sprintf_s(lpDisplayBuf, "Error Creating SERIALIO Comm Object with error:\r\n (%d): %s",dw,W2A(lpMsgBuf));<br />
		MessageBoxW(NULL, A2W(lpDisplayBuf), L"Error", MB_OK); 		<br />
	}<br />
}<br />

When I send a data packet to the device, I am expecting to receive the response immediately. So, I have a function called SendForResponce, which is as follows:

<br />
LPCSTR SerialIO::SendforResponse(LPCSTR outstr,<br />
								char abortc,<br />
								DWORD Timeout,<br />
								DWORD ch_delay){<br />
	DWORD count,mask;<br />
	char c='\0';<br />
	int i, canceled=0;<br />
	DWORD cTime=GetTickCount();//Current start time (milliseconds)<br />
	COMMTIMEOUTS timeouts,oldtimeouts;<br />
	DWORD pauset;<br />
	if(abortc!='\0'){<br />
		dcb.EvtChar=abortc;<br />
		SetCommState(idCommDev,&dcb);<br />
		mask=EV_RXCHAR|EV_RXFLAG;<br />
	}<br />
	else {mask=EV_RXCHAR;}<br />
	SetCommMask(idCommDev,mask);<br />
	//Adjust timeout to reflect user request.<br />
	GetCommTimeouts(idCommDev,&oldtimeouts);<br />
	timeouts=oldtimeouts;<br />
	timeouts.ReadIntervalTimeout=0;<br />
	timeouts.ReadTotalTimeoutMultiplier=0;<br />
	timeouts.ReadTotalTimeoutConstant=Timeout;<br />
	SetCommTimeouts(idCommDev,&timeouts);<br />
<br />
	PurgeComm(idCommDev,PURGE_RXCLEAR|PURGE_TXCLEAR);<br />
	buffer[0]='\0';<br />
	if(strlen(outstr)){<br />
		if(ch_delay){<br />
			for(i=0;(unsigned)i<strlen(outstr) && !canceled;i++){<br />
				pauset=GetTickCount();<br />
				if(!WriteFile(idCommDev,(LPCVOID)(&(outstr[i])),(DWORD)1L, &count,NULL)){ <br />
					canceled=1;<br />
				}<br />
				while((GetTickCount()-pauset)<ch_delay); //pause between characters.<br />
			}<br />
		}<br />
		else if(!WriteFile(idCommDev,(LPCVOID )outstr,(DWORD)strlen(outstr), &count,NULL)){canceled=1;}<br />
		if(!canceled && (GetTickCount()-cTime)<Timeout){<br />
			for(i=0;c!='\r' && c!='\n' && c!=abortc;i++){<br />
				if(!ReadFile(idCommDev,&c,1,&count,NULL)){MessageBoxW(NULL,(LPCTSTR)"SERIALIO Read Failed",(LPCTSTR)"Debug",MB_OK);;}<br />
				else{<br />
					if((GetTickCount()-cTime)>=Timeout){<br />
						strcpy_s(buffer,TIMEOUT_STR);<br />
						c=abortc;<br />
					}<br />
					else if(c==abortc){<br />
						buffer[0]='\0';<br />
						canceled=1;<br />
					}<br />
					else if((int)c==8 && i>0){<br />
						i-=2;<br />
						buffer[i+1]='\0';<br />
					}<br />
					else if(c!='\r' && c!='\n'){<br />
						buffer[i]=c;<br />
						buffer[i+1]='\0';<br />
					}<br />
				}<br />
			}//end for<br />
		}//end if(!canceled)<br />
	}//end if(WriteFile(idCommDev,(LPCVOID )outstr,(DWORD)strlen(outstr),&count,NULL))<br />
	else {<br />
	if(canceled){PurgeComm(idCommDev,PURGE_RXCLEAR);}<br />
	SetCommTimeouts(idCommDev,&oldtimeouts);<br />
	return buffer;<br />
}<br />

There are 10 kinds of people, those that understand binary and those that don't.

Jonathan Davies31-Mar-10 4:14

Jonathan Davies

31-Mar-10 4:14

Try using the a port monitor such as PortMon which will show you exactly what instructions the port is getting (rather than code showing what you think it is getting) and it will also show exatly what is being sent/received.

jeron131-Mar-10 5:19

jeron1

31-Mar-10 5:19

rick7423 wrote:
When I use Hyper-Terminal and set the properties to 4800, n,8,1,Flow Control to use XON/XOFF, I get response every time.

Shouldn't then the following be set to TRUE?

dcb.fInX=FALSE;
dcb.fOutX=FALSE;

rick742331-Mar-10 5:32

31-Mar-10 5:32

Yes, but when I set those state values the utility just hangs.

I am using the PORT monitor and I am starting to think that the input timeouts/buffer receive portion may be the issue. I can replicate the port settings exactly to what Hyper-terminal is doing but it appears as though the receive portion is just hanging now (open comm state acts like an application hang).

Port Monitor is a godsend, that tool is helping alot.

There are 10 kinds of people, those that understand binary and those that don't.

Vaclav_31-Mar-10 6:19

Vaclav_

31-Mar-10 6:19

Would it help if I send you my code? It is not complete (and not if one fuction either)and may confuse the issue.
I am currently working on COM application and it should be done using "assynchronous code". Your ReadFile last parameter should point to OVELLAPED structure to do so.
FYI I have found two conflicting API descriptions of ReadFile when used for COM port. As far as I can tell you code look OK, however, I have learn that one needs to keep track of various API retrun values.
I for example check the last error of ReadFile before even looking at the return value.
Vaclav

rick742331-Mar-10 6:56

31-Mar-10 6:56

Actually, yes, that would be good. I have looked at several classes found online but most were written years ago and have issues with VC2K5.

Even if your code points me in the right direction, that is good.
send to: rickr at nurserysupplies dot com

There are 10 kinds of people, those that understand binary and those that don't.

rick742331-Mar-10 9:34

31-Mar-10 9:34

Could this be a problem with the WIDE characters? With the original application (Visual Studio 6), I did not use wide chars at all. This one has it turned on by default. I never thought it would cause a problem, but it may here.

Any thoughts on this?

There are 10 kinds of people, those that understand binary and those that don't.

rick74231-Apr-10 2:24

1-Apr-10 2:24

By default, the VS2K5 project set the Character set to "Use Unicode Character set". Could this be part of the problem?

If so, is there any way to force the Serial Comm class to NOT be Uni-Code?

There are 10 kinds of people, those that understand binary and those that don't.

jeron11-Apr-10 5:09

jeron1

1-Apr-10 5:09

Could you use PortMon to logdata from your app, then look at it with DEBUG to see exactly what hex data is in there? If the data is not what you (or the receiving device) wants then yes, unicode could be a problem. Can't you disable unicode for the entire application if it's not needed?

rick74231-Apr-10 6:50

1-Apr-10 6:50

I am in the process of converting to non-Unicode now, but man, it generated HUNDREDS of errors. This will take awhile to resolve.

I was hoping that it would be easier to force the data string to ANSI, but am not sure exactly how to do that. Blush | :O

There are 10 kinds of people, those that understand binary and those that don't.

access dynamically allocated structure

jeron11-Apr-10 9:33

jeron1

1-Apr-10 9:33

Take a look at W2A() and T2A() macros and see if they might help.

rupeshkp72831-Mar-10 2:07

rupeshkp728

31-Mar-10 2:07

I want to fill a structure and then print it.
How to print the values of the structue?
The structure is:

#define UINT32 unsigned int
#define INT32 int
#define UCHAR unsigned char

typedef struct CheckSumPair
{
UINT32 weakcs; // The weak, rolling Adler32 checksum.
UCHAR StrongCS[10];
};

I have dynamically allocated memory to it as folows.

CheckSumPair* CSPair = (CheckSumPair*)malloc(sizeof(CheckSumPair)*10);

for(int x = 0;x < 10;x++)
{
CSPair->weakcs = (UINT32)x+1;
strncpy((char*)CSPair->StrongCS,(char*)"XYZ",10);
strncpy((char*)CSPair->StrongCSString,(char*)"CEDVCD",10*2+1);
}

Now print the values
for(int x = 0;x < 10;x++)
printf("%d %s %s\n\n",CSPair[x]->.weakcs,CSPair[x]->StrongCS,CSPair[x]->StrongCSString);

While printing the values I get the following error:

error C2232: '->CheckSumPair::StrongCS' : left operand has 'struct' type, use '.'
error C2819: type 'CheckSumPair' does not have an overloaded member 'operator ->'
see declaration of 'CheckSumPair'

Eugen Podsypalnikov31-Mar-10 2:29

Eugen Podsypalnikov

31-Mar-10 2:29

Try this access in your loops Smile | :)

{
  CheckSumPair* psTempPair = (CheckSumPair*) ((BYTE*)CSPair + sizeof(CheckSumPair) * x);
  // psTempPair->Member1
  // psTempPair->Member2
}

virtual void BeHappy() = 0;

Richard MacCutchan31-Mar-10 2:35

Richard MacCutchan

31-Mar-10 2:35

Eugen Podsypalnikov wrote:
CheckSumPair* psTempPair = (CheckSumPair*) ((BYTE*)CSPair + sizeof(CheckSumPair) * x);

All this casting is unnecessary and prone to error, the compiler handles pointer arithmetic automatically.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Eugen Podsypalnikov31-Mar-10 2:37

Eugen Podsypalnikov

31-Mar-10 2:37

In this case - it is necessary,
since sizeof(CheckSumPair*) != sizeof(CheckSumPair) ! Smile | :)

virtual void BeHappy() = 0;

Richard MacCutchan31-Mar-10 3:03

Richard MacCutchan

31-Mar-10 3:03

Pointers to structures can be incremented by simple expressions thus:

CSPair++;

that is all that is needed to point to the next entry in the array.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Eugen Podsypalnikov31-Mar-10 3:09

Eugen Podsypalnikov

31-Mar-10 3:09

Yes, they can !!! Big Grin | :-D

You are right, Richard !
(probably I was intricated by malloc... Big Grin | :-D

)
Thank you very much ! Thumbs Up | :thumbsup:

virtual void BeHappy() = 0;

rupeshkp72831-Mar-10 2:35

rupeshkp728

31-Mar-10 2:35

thanks eugen for the reply
that was a typing mistake
issue is resolved by using
CheckSumpair[x].memberN;
.
.
.
since i am using [] operator to access pointer no need of using ->