Post by thread:[OT]: Using Visual Basic with RS232 Read

part 1 6207 bytes content-type:text/plain; (decoded 7bit) ----- Original Message ----- From: "Michael Rigby-Jones" <spam_OUTmrjonesTakeThisOuTNORTELNETWORKS.COM> To: <.....PICLISTKILLspam@spam@MITVMA.MIT.EDU> Sent: Friday, August 04, 2000 2:58 AM Subject: Re: [OT] Using Visual Basic with RS232 Read > > {Original Message removed} part 2 86 bytes content-type:application/octet-stream; (decode) part 3 794 bytes content-type:application/octet-stream; (decode) part 4 14288 bytes content-type:application/octet-stream; (decode) part 5 142 bytes (decode)

" I implemented your suggestions as best I could. It seems to work except for one glitch: If a byte value of zero is sent, the program doesn't seem to recognize it. It seems that any value from 0 to 255 should be valid." The old 'error on Null' scenario. *I believe* we worked out a solution by utilizing an "on error" statement and 'trapped' for the condition where a Null char is rcvd. IIRC - that was the only solution we had found at the time (VB5 - a couple of years back). Part of our protocol used on the Motorola Creatalink II XT called for the use of nulls (0x00) as padding chrs - and we ran into a prob where VB would - and things are getting foggy now - would "error" when reading a null from the comm port *even though* a char should have been there to 'pull' out. Using an "On ERROR" statement - we trapped to the ON ERROR routine and simply stuck a 'null' into the string. IIRC that is ... Jim ----- Original Message ----- From: "Dan Mulally" <dtconKILLspamRAPIDNET.COM> To: <.....PICLISTKILLspam.....MITVMA.MIT.EDU> Sent: Monday, August 07, 2000 5:25 PM Subject: Re: [OT]: Using Visual Basic with RS232 Read ----- Original Message ----- From: "Michael Rigby-Jones" <EraseMEmrjonesspam_OUTTakeThisOuTNORTELNETWORKS.COM> To: <PICLISTspam_OUTMITVMA.MIT.EDU> Sent: Friday, August 04, 2000 2:58 AM Subject: Re: [OT] Using Visual Basic with RS232 Read > > {Original Message removed}

> Thanks Mike, > I implemented your suggestions as best I could. It seems to work > except > for one glitch: If a byte value of zero is sent, the program doesn't seem > to > recognize it. It seems that any value from 0 to 255 should be valid. Is > there something unique about 0 when using strings perhaps? Maybe this was > also part of my original problem. I'm also wondering if there is a way to > clear MSComm1.CommEvent which is read only. > My modified code is attached. > Thanks for the useful suggestions. > > Dan Mulally > << File: lloydspc.vbw >> << File: lloydspc.vbp >> << File: lloydspc.frm > >> > > Ooops, sorry about that. This is due the the Comm control expecting ANSI characters and Character 0 is a Null character which it dosen't like. You can fix this by setting Comm1.InputMode = comInputModeBinary. This means the Input method of the Comm control returns a byte array rather than a string so your routines will have to be modified a tiny bit. The VB Example shows how to do this using a Variant, which I don't usualy like using but it does make the code very simple. Dim Buffer as Variant Dim bytArray() as Byte ' Get the contents of the Comm buffer Buffer = MSComm1.Input 'Convert to byte array bytArray = Buffer ' Send the data to your display routine For intCount = LBound(bytArray) To Ubound(bytArray) DisplayChar(bytArray(intCount)) Next intCount Hope this works, I don't have two PC's available right noe to test this. Cheers Mike -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Mike, Your code seems to work like a charm! Thanks. Dan ----- Original Message ----- From: "Michael Rigby-Jones" <@spam@mrjonesKILLspamNORTELNETWORKS.COM> To: <KILLspamPICLISTKILLspamMITVMA.MIT.EDU> Sent: Tuesday, August 08, 2000 1:00 AM Subject: Re: [OT]: Using Visual Basic with RS232 Read > > Thanks Mike, > > I implemented your suggestions as best I could. It seems to work > > except > > for one glitch: If a byte value of zero is sent, the program doesn't seem > > to > > recognize it. It seems that any value from 0 to 255 should be valid. Is > > there something unique about 0 when using strings perhaps? Maybe this was > > also part of my original problem. I'm also wondering if there is a way to > > clear MSComm1.CommEvent which is read only. > > My modified code is attached. > > Thanks for the useful suggestions. > > > > Dan Mulally > > << File: lloydspc.vbw >> << File: lloydspc.vbp >> << File: lloydspc.frm {Quote hidden}> > >> > > > > > Ooops, sorry about that. This is due the the Comm control expecting ANSI > characters and Character 0 is a Null character which it dosen't like. You > can fix this by setting Comm1.InputMode = comInputModeBinary. This means > the Input method of the Comm control returns a byte array rather than a > string so your routines will have to be modified a tiny bit. > > The VB Example shows how to do this using a Variant, which I don't usualy > like using but it does make the code very simple. > > Dim Buffer as Variant > Dim bytArray() as Byte > > > ' Get the contents of the Comm buffer > > Buffer = MSComm1.Input > > 'Convert to byte array > > bytArray = Buffer > > ' Send the data to your display routine > > For intCount = LBound(bytArray) To Ubound(bytArray) > DisplayChar(bytArray(intCount)) > Next intCount > > > Hope this works, I don't have two PC's available right noe to test this. > > Cheers > > Mike > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu>