C / C++ / MFC

20-Apr-04 23:37

Hello,

This arrives at my serial port:

924.09,-4.06,676.26,0.156488,-0.653856,-0.714853,-0.192273

<br />
CString nx;<br />
<br />
	 while(port.Read(cReceivedChar, 1 , overlapped, &dwBytesRead)) <br />
	  {<br />
	    <br />
		nx += cReceivedChar[0];<br />
	    	SetDlgItemText(IDC_SHIFT_X,("%c", nx));<br />
          }<br />

but my dialog only shows 06,676 ?? Why?

Thanks, Mark

jmkhael21-Apr-04 0:10

jmkhael

21-Apr-04 0:10

What is in nx?

Try a MessageBox call

and why not a SetDlgItemText(IDC_SHIFT_X,(LPCSTR)nx);

Papa

while (TRUE)
Papa.WillLove ( Bebe ) ;

macmac3821-Apr-04 1:20

21-Apr-04 1:20

Hello,

nx contains nothing when i trace it.

cReceivedChar[0] contains confused values from the string..

I think the whole procedure must be rewied

Thanks, Mark

David Crow21-Apr-04 2:44

21-Apr-04 2:44

CString nx;
char cReceivedChar;

while(port.Read(&cReceivedChar, 1, overlapped, &dwBytesRead)) 
    nx += cReceivedChar;

SetDlgItemText(IDC_SHIFT_X, nx);

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

macmac3821-Apr-04 22:31

21-Apr-04 22:31

char cReceivedChar; is not working (other type expected)

<br />
BOOL CSerialPort::Read(void* lpBuf, DWORD dwCount, OVERLAPPED& overlapped, DWORD* pBytesRead)<br />

Thanks, Mark

David Crow22-Apr-04 2:04

22-Apr-04 2:04

How are you calling the Read() method?

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

macmac3822-Apr-04 2:13

22-Apr-04 2:13

while(port.Read(cReceivedChar, 1 , overlapped, &dwBytesRead))

Thanks, Mark

David Crow22-Apr-04 2:15

22-Apr-04 2:15

The first parameter is supposed to be a pointer.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

macmac3822-Apr-04 2:32

22-Apr-04 2:32

<br />
<br />
char *cReceivedChar;<br />
<br />
while(port.Read(cReceivedChar, 1, overlapped, &dwBytesRead))

Thanks, Mark

David Crow22-Apr-04 2:52

22-Apr-04 2:52

But then you'd have to allocate one byte of memory from the heap (i.e., cReceivedChar = new char). Why not just use this instead:

char cReceivedChar;
while(port.Read(&cReceivedChar, 1, overlapped, &dwBytesRead)) 
    ...

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

macmac3823-Apr-04 2:26

23-Apr-04 2:26

yep, it seems to be better to use a reference.

with this procedure my string output is only "0.1922"

remember incoming:

924.09,-4.06,676.26,0.156488,-0.653856,-0.714853,-0.192273

It looks like that the first values running through the digits in the dialog..mmh?? Is this so complicate to give out the full string?

Thanks, Mark

David Crow23-Apr-04 3:35

23-Apr-04 3:35

macmac38 wrote:
yep, it seems to be better to use a reference.

My example was not a reference. It was a pointer, exactly what the Read() method is expecting. Had it wanted a reference, the signature would look like:

BOOL Read(void& lpBuf, ...);

You mentioned that 924.09,-4.06,676.26,0.156488,-0.653856,-0.714853,-0.192273 is arriving at the serial port. How are you verifying this?

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

macmac3823-Apr-04 3:55

23-Apr-04 3:55

This is the position string from a robot arm and every time the same format.

x,y,z shift and quaternion 1-4

I have to extract them later from the string in float variables

Thanks, Mark

David Crow23-Apr-04 4:15

23-Apr-04 4:15

That's all well and good, but in your original post, you indicated that "This arrives at my serial port," implying that the data is indeed there. That's why I asked how you were verifying it.

In the while loop that you are using to read the incoming data, how many times does the loop execute?

After each call to Read(), what is the value of dwBytesRead?

If the incoming data is always in the same format and is always less than X bytes, you might could use this instead:

char received[X];
port.Read(received, sizeof(received), overlapped, &dwBytesRead);
received[dwBytesRead] = '\0';

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

macmac3823-Apr-04 5:01

23-Apr-04 5:01

<br />
received[dwBytesRead] = '\0';<br />

what does this line mean? I have "access violation" with this line.

Thanks, Mark

David Crow23-Apr-04 5:26

23-Apr-04 5:26

macmac38 wrote:
what does this line mean?

It appends a \0 character to the end of the string.

macmac38 wrote:
I have "access violation" with this line.

How big is the received array, and what is the value of dwBytesRead?

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

macmac3823-Apr-04 6:17

23-Apr-04 6:17

<br />
 char received[40];<br />
	  <br />
 port.Read(received, sizeof(received), overlapped, &dwBytesRead);<br />
<br />
          TRACE( "Bytes read: %d",dwBytesRead);<br />
	  <br />
	  received[dwBytesRead] = '\0';<br />
       <br />
	  SetDlgItemText(IDC_SHIFT_X, received);<br />
<br />

Bytes read: 1Bytes read: -858993460Bytes read: -858993460Bytes read: -858993460

Thanks, Mark

David Crow23-Apr-04 6:40

23-Apr-04 6:40

macmac38 wrote:
TRACE( "Bytes read: %d",dwBytesRead);

Since dwBytesRead is a DWORD, you'll need to use the %lu format.

Nonetheless, if received[] is only 40 bytes, trying to access the -858993460th position, or any value outside of 0-39, is obviously wrong. Check the return value of Read() beforehand.

In your original post, you indicated that 58 characters were being sent to the serial port. You'll need room for that plus one more so received[] should be 59 not 40. This is not the root of the problem, however, but will eventually need to be addressed.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

macmac3825-Apr-04 22:47

25-Apr-04 22:47

<br />
<br />
	  char received[59];<br />
<br />
	  port.Read(received, sizeof(received), overlapped, &dwBytesRead);<br />
<br />
	  <br />
      TRACE( "Bytes read: %lu",dwBytesRead);<br />
	  <br />
	  received[dwBytesRead] = '\0';<br />
       <br />
	  SetDlgItemText(IDC_SHIFT_X, received);<br />

Bytes read: 1

I donn't know where's the problem? Normaly it seems easy..?
Like to solve it today Wink | ;-)

Thanks, Mark

David Crow26-Apr-04 2:18

26-Apr-04 2:18

macmac38 wrote:
I donn't know where's the problem?

Are you sure a problem exists? Maybe there was only one byte available to read.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

macmac3826-Apr-04 2:25

26-Apr-04 2:25

But this Byte output like: j
which means no character in it?
But the full string is arriving..

if i don't use this line:

received[dwBytesRead] = '\0';

the output is:

-0.714853,-0.192273jjjjjjjjjjjjjjjjj

Thanks, Mark

David Crow26-Apr-04 2:31