Serial Port /COM Port UDF

martin · July 1, 2008

Hi Martin,
Looks like you've made a pretty awesome script!

Thanks.

I'm a newbie to autoit and COM communication am desperately trying to communicate with some hardware of mine. I have a laser micrometer that is set to measure diameters of different objects and then puts their profiles into AutoCAD. I've been able to automate the importation into AutoCAD and everything but have failed in communicating with my micrometer using autocad. The original owner of the micrometer had it set up to hyperterminal but that software is not useful for my application. Right now I am trying to just sucessfully communicate but in theory I want to store the data read from the com port into an array. I can do that but gettting data into a variable from the comm port is my problem.

Right now when reading the lasermicrometer manual it reads this for serial port communication:

The number I want to send it is 68 (which is to read the average diamater) and at this moment I have a code that creates a gui and when I press a button it should return the measurement but it is not working. I don't understand what I should put as a linefeed or carriage return and maybe that is the problem. But here is my script right now.

If anyone could help me understand why my data is not being returned correctly their help would be greatly appreciated.

Thanks,

J

The SendString function only sends exactly what you ask it to. If you need a CR or line feed added then you must add it like this

I'm not sure why you have [b]<A>[/b] when the manual says 68. I would have expected [b]<68>[/b]. Or if you think the Ascii code is needed then [b]<65>[/b].
 _CommSendString("?J0/<A>" & @CR)

The _CommSetPort needs to have a variable for the second parameter. If there is an error then this variable will contain the error message. The documentation needs to be improved here because I state that this parameter is a string whereas I should have said a variable for holding the error string. (I show it as a variable). I will improve the description of this.

The laser manual says <#> but, unless you are sure on this point, I would try without the angle brackets as well in case the author meant <#> to represent the number.

I'm not sure why you have <A> when the manual says 68. I would have expected <68>, or if you think the Ascii code is needed then <65>.

Edited July 1, 2008 by martin

Champak · July 7, 2008

How can virtual COM ports be made with this? ...if it's possible.

martin · July 7, 2008

How can virtual COM ports be made with this? ...if it's possible.

No, it only connects to existing COM ports as seen in device manager under Ports.

koushik · July 10, 2008

cant get it working. The example program runs an error.

I guess I am not able to access the dll. I cannot get the version or list ports.

I am using windows xp pro 64 bit OS multicore - Should it be a problem?

Thanks

Koushik

martin · July 11, 2008

cant get it working. The example program runs an error.
I guess I am not able to access the dll. I cannot get the version or list ports.
I am using windows xp pro 64 bit OS multicore - Should it be a problem?
Thanks
Koushik

What errors do you get?

I don't think it should be a problem running on xp pro 64 bit but I have not tested it on that OS. It runs on Vista 64 bit as a 32 bit application.

You cannot mix 64 bit and 32 bit apps in the same process. That is a 64 bit application cannot use a 32 bit dll AFAIK.

DrJeseuss · July 12, 2008

Having trouble getting things going correctly. Here's a bit of code I'm trying to make work

CODE

#include <CommMg.au3>

Local $ComError

;~ Dialog to request Com port#, i.e. 1 for Com1

$ComPort = InputBox("Comport#", "Enter Com port number")

$ComBaud = 9600

$ComDataBits = 8

$ComParity = 0

$ComStopBits = 1

;~ Configure Com port settings

_CommSetPort($ComPort,$ComError,$ComBaud,$ComDataBits,$ComParity,$ComStopBits,0)

MsgBox(0,'Com Set',"Com"&$ComPort&" @"&$ComBaud&" baud "&$ComDataBits&$ComParity&$ComStopBits)

$Bytes = "0xF4570100B4"

MsgBox(0,'Data to Send',$Bytes)

$Numbytes = BinaryLen(Binary($Bytes))

MsgBox(0,'Data Length',$NumBytes)

$Struct1 = DllStructCreate("byte[" & $Numbytes & "]")

DllStructSetData($Struct1, 1, $Bytes)

MsgBox(0,"DllStruct","Struct Size: " & DllStructGetSize($Struct1) & @CRLF & _

"Struct pointer: " & DllStructGetPtr($Struct1) & @CRLF & _

"Data:" & @CRLF & _

DllStructGetData($Struct1,1))

$ComOut = _CommSendByteArray(DllStructGetPtr($Struct1), $Numbytes, 1)

MsgBox(0,'Data Sent',$ComOut)

All dialogs (There just for debugging purposes) show correct information, but I never get the final dialog for Data sent. Instead, the script stops and I get "Exit code: -1073741819". The best I can tell is the problem has to be in my _CommSendByteArray line. Anybody see what I did wrong there? Or is the issue that the _CommSetPort isn't working properly? I'm testing it with Com5 which is a virtual Com that is available. I've connected to it with other terminal without trouble.

Also, while I'm here... I plan to use _CommReadByteArray to read the response data back from the buffer. Below is the code I intended to use, but can't test as my code isn't getting that far. Anyone see issues with it:

CODE

$WaitingForData = 1

MsgBox(0,'Ready to recieve','Send data now')

While $WaitingForData = 1

$NumBytes = _CommGetInputCount() ;Count number of characters in buffer

if $NumBytes > 0 then $WaitingForData = 0

WEnd

$Struct2 = DllStructCreate("byte[" & $Numbytes & "]")

DllStructSetData($Struct2, 1, $Bytes)

MsgBox(0,"DllStruct","Struct Size: " & DllStructGetSize($Struct2) & @CRLF & _

"Struct pointer: " & DllStructGetPtr($Struct2) & @CRLF & _

"Data:" & @CRLF & _

DllStructGetData($Struct2,1))

$ComIn = _CommReadByteArray(DllStructGetPtr($Struct2), $Numbytes, 1)

MsgBox(0,'Response recieved',$ComIn)

$Struct2= 0

My goal here is to send hex bytes, wait a moment, and grab the response into a variable. The command will generally be only 5-10 bytes, the response will be 60-70 bytes. I'd like to use SendByteArray and ReadByteArray as dealing with single bytes at a time is too cumbersome. Thanks for any help I can get!

Edited July 12, 2008 by DrJeseuss

DrJeseuss · July 12, 2008

As an update the code below is working. The script waits for characters in buffer, then grabs the bytes. The bytes are checked as valid, if not wait again, if valid respond back with bytes. It appears the issue I was having was due to a quick rewrite of CommMg to allow for a nonstandard baud. I've notified Martin of this, though he is on holiday, so I'll have to wait.

CODE

#include <CommMg.au3>

Local $ComError

$Version = _CommGetVersion(1)

MsgBox(0,'DLL Version',$Version)

;~ Dialog to request Com port#, i.e. 1 for Com1

$ComPort = InputBox("Comport#", "Enter Com port number")

;~ $ComPort = 1

$ComBaud = 9600

$ComDataBits = 8

$ComParity = 0

$ComStopBits = 1

;~ Configure Com port settings

_CommSetPort($ComPort,$ComError,$ComBaud,$ComDataBits,$ComParity,$ComStopBits,0)

;~ COM should be open now. Begin Rx/Tx loop

;~ Wait to recieve command

$NotChecked = 1

While $NotChecked = 1

$WaitingForData = 1

While $WaitingForData = 1

$NumBytes = _CommGetInputCount() ;Count number of characters in buffer

if $NumBytes > 0 then $WaitingForData = 0 ;if characters exist continue

WEnd

$Struct2 = DllStructCreate("byte[" & $Numbytes & "]") ;create struct2 based on buffer size

$ComIn = _CommReadByteArray(DllStructGetPtr($Struct2), $Numbytes, 1)

$ComIn = DllStructGetData($Struct2,1)

MsgBox(0,'Data recieved',$ComIn) ;display bytes received

$Struct2= 0 ;clear struct2 from memory

if $ComIn = "0xF4570100B4" then $NotChecked = 0

WEnd

;~ Bytes recieved, now respond

;~ The code below uses SendByteArray to allow an entire string to be sent at once

$Bytes = "0xF4950124810B0C35000040000035001C81A68A1D4D19020040D4E19680E8A0A202007F841B07A10040044D3600000

0004000E565FF0E5D00106C00005A000005FE6FBE"

$Numbytes = BinaryLen(Binary($Bytes))

$Struct1 = DllStructCreate("byte[" & $Numbytes & "]")

DllStructSetData($Struct1, 1, $Bytes)

$ComOut = _CommSendByteArray(DllStructGetPtr($Struct1), $Numbytes, 1)

$Struct1 = 0 ;clears struct from memory

;~ Command sent. Start listening to get response

;~ At end of Rx/Tx session, close port to release

_Commcloseport()

martin · July 13, 2008

As an update the code below is working. The script waits for characters in buffer, then grabs the bytes. The bytes are checked as valid, if not wait again, if valid respond back with bytes. It appears the issue I was having was due to a quick rewrite of CommMg to allow for a nonstandard baud. I've notified Martin of this, though he is on holiday, so I'll have to wait.

The dll I made for DrJeseuss to test special baud rates had no byte array functions! Whoops. New version uploaded overwriting the previous one.

EDIT: 14th July. DrJeseuss reports that it now works in initial tests.

Edited July 14, 2008 by martin

DrJeseuss · July 14, 2008

Martin and All,

I have successfully used a custom baud rate and connected properly! I have Byte data going to and from the Com without any issues at all. I'm still working on getting the code cleaned up for speed and clarity. As soon as that's done, I'll post a copy. Thanks again Martin!

JusGellin · August 31, 2008

I'm having trouble reading Chr(0) using _CommReadByte(). I've modified the example, but it continuously has 0. How can I read Chr(0) or is there a better way of doing this? Thanks

While 1
    
   ;gets characters received returning when one of these conditions is met:
   ;receive @CR, received 20 characters or 200ms has elapsed
   ;$instr = _CommGetstring()
    $instr = _CommReadByte()
   ;$instr = _CommReadChar()
   ;$scroll = StringInStr($instr,@CR)
    If $instr > -1 Then;if we got something
       ;$instr = Hex($instr,2) & " "
        if $instr < 32 Then
            $instr = "[" & Hex($instr,2)& "]"
        Else    
            $instr = Chr($instr)
        endif
        If GUICtrlRead($Checkbox1) = $GUI_CHECKED Then $instr = StringReplace($instr, @CR, @CRLF)
        $lines = GUICtrlRead($Edit1)
        $charcount = StringLen($lines)
        _GUICtrlEdit_SetSel($Edit1, $charcount, $charcount)
        If $charcount > 10000 Then GUICtrlSetData($Edit1, StringRight($lines & $instr, 8000))
        _GUICtrlEdit_ReplaceSel($Edit1, $instr,False)
        _GUICtrlEdit_Scroll($Edit1, $SB_SCROLLCARET)
       ;If $scroll Then _GUICtrlEditLineScroll($edit1,0,_GUICtrlEditGetLineCount($edit1) - 14)
    EndIf
    
WEnd

martin · August 31, 2008

I'm having trouble reading Chr(0) using _CommReadByte(). I've modified the example, but it continuously has 0. How can I read Chr(0) or is there a better way of doing this? Thanks

While 1
    
  ;gets characters received returning when one of these conditions is met:
  ;receive @CR, received 20 characters or 200ms has elapsed
  ;$instr = _CommGetstring()
    $instr = _CommReadByte()
  ;$instr = _CommReadChar()
  ;$scroll = StringInStr($instr,@CR)
    If $instr > -1 Then;if we got something
      ;$instr = Hex($instr,2) & " "
        if $instr < 32 Then
            $instr = "[" & Hex($instr,2)& "]"
        Else    
            $instr = Chr($instr)
        endif
        If GUICtrlRead($Checkbox1) = $GUI_CHECKED Then $instr = StringReplace($instr, @CR, @CRLF)
        $lines = GUICtrlRead($Edit1)
        $charcount = StringLen($lines)
        _GUICtrlEdit_SetSel($Edit1, $charcount, $charcount)
        If $charcount > 10000 Then GUICtrlSetData($Edit1, StringRight($lines & $instr, 8000))
        _GUICtrlEdit_ReplaceSel($Edit1, $instr,False)
        _GUICtrlEdit_Scroll($Edit1, $SB_SCROLLCARET)
      ;If $scroll Then _GUICtrlEditLineScroll($edit1,0,_GUICtrlEditGetLineCount($edit1) - 14)
    EndIf
    
WEnd

I don't really understand. The function _ComReadByte returns a string not a number so that might have confused you. So if you receive a byte of value 0 the function returns trhe string '0'. The reason I did that was so that is not so clear to me now but it was supposed to get round some problem.

Can you receive other characters ok?

JusGellin · August 31, 2008

I don't really understand. The function _ComReadByte returns a string not a number so that might have confused you. So if you receive a byte of value 0 the function returns trhe string '0'. The reason I did that was so that is not so clear to me now but it was supposed to get round some problem.
Can you receive other characters ok?

After receiving your reply, I looked further and found 2 problems. 1)I was using the standard Hyperterminal to send the characters to this. I would paste the chr(0) etc into it to transmit but found that it would send all other characters except chr(0). 2) Understanding better what you said, I changed the condition to compare as as string with "".

If $instr <> "" Then;if we got something

So I did a serial loopback instead and made the application send and receive the control characters and it worked properly. Wow! thanks for this wonderful serial port application. I can use it when I need to do some quick testing of serial devices. Thanks again for your help.

Beamer145 · October 9, 2008

Hi Martin,

First of all, thanks for the udf !

But (here comes the but) it seems I am running into some hard limitations of it.

I am trying to communicate with a system of which at a given moment I request a memory dump via the command "D2 F0040000 100"

The response looks like

D2 F0040000 100 (each entered char is echoed, after the CR, the response follows immediately)

> f0040000: 0000 ffff 0000 0000 0000 0000 0000 0000

> f0040010: 000a 00f5 0000 0000 000a 00f5 0000 0000

> f0040020: 000a 00f5 0000 0000 0000 0000 0000 0000

[...]

> f00401f0: 0000 0000 0000 0000 0000 0000 0000 0000

-

No matter what I try to do (_CommGetString or _CommGetLine), I always only manage to get the first 3 lines and the last -.

Is it possible the problem is related to the fact that some internal buffer gets filled up because commg is not reading it out soon enough ?

I've created a log from the communication interaction with teraterm vs commg which you can find at marie.dommel.be/SerialProblem.zip

The behaviour is totally different, with teraterm readin out the info as soon as its available, while commg seems to wait for a read api to be called before it does an IRP_MJ_READ.

However, I in my latest attemp to deal with the problem I immediately start polling after sending the last letter of the command, and still I only get the first 3 lines. The difference between the write and the read is 30ms for terraterm and 60ms for commg which is more are less comparable so I am assuming teraterm does some more tricks to grab everything.

One thing I see in the teraterm logs and not in the commg ones is IRP_MJ_DEVICE_CONTROL (IOCTL_SERIAL_WAIT_ON_MASK).

( I am not familiar with these IRP calls)

Apart from that, there are a few more less important quirks/bugs in commg

- It seems that if you specify a wait time for reading a line (eg $sReceivedData = _CommGetLine(@CR, 0, 3000) ), he happily starts to busy wait ! (1 CPU core is completely occupied by commg)

- _CommSwitch does not take into account the fact that the DLL may not yet be opened.

- Even if you make sure the dll is opened by another call (eg _CommGetVersion), _CommSwitch fails if no port has been set yet.

- _ComClosePort closes the dll ! It does not take into account that you may be using several ports.

- Maybe it would be cleaner to foresee a _commg init/uninit pair to deal with opening/closing the dll, and just return an error when a call is made before _commg_init

* Error behaviour needs some cleaning up (the mechanism (@error vs return value) + the error values (success is sometimes 1, sometimes 0) ). (make set of consts to abstract the concrete values eg _COMMMG_SUCCESS, ... )

As a reference, I have added the test code to check for the first issue (note: I add a delay between sending the individual keys, because the target sometimes does not follow):

$l_bEnablePolling = 1
        
        ; I don't care, used as init call
        _CommGetVersion()
        
        if ( _CommSwitch( 1 ) == -1 ) Then
            MsgBox ( 0, "Error", "comswitch" )          
        EndIf

        $l_sErr = ""
        If ( _CommSetPort(1, $l_sErr, 115200, 8, 0, 1, 0) == 0 ) Then
            MsgBox ( 0, "Error", "Com port creation failed :" & $l_sErr )           
        EndIf
        
        if ( _CommSwitch( 2 ) == -1 ) Then
            MsgBox ( 0, "Error", "comswitch" )          
        EndIf
        
        $l_sErr = ""
        If ( _CommSetPort(4, $l_sErr, 115200, 8, 0, 1, 0) == 0 ) Then
            MsgBox ( 0, "Error", "Com port creation failed :" & $l_sErr )           
        EndIf
                    
        if ( _CommSwitch( 1 ) == -1 ) Then
            MsgBox ( 0, "Error", "comswitch" )          
        EndIf
        
        $l_sCommand = "D2 F0040000 100"
        while (1)           
            $l_sCommand = InputBox("Giveth thy command", "...", $l_sCommand)                
            
            $l_sCommand = $l_sCommand & @CRLF
            msgbox (1, "info", "[" & $l_sCommand & "] -> " & string(StringLen($l_sCommand) ))
            
            $l_nCommandLength = StringLen( $l_sCommand )
            $l_nCharIndex = 1
            $l_nIntermediateResult = $COMMGDRIVER_SUCCESS
            while   (   ($l_nIntermediateResult == $COMMGDRIVER_SUCCESS ) _
                    and ( $l_nCharIndex <= $l_nCommandLength ) _
                    )
                $l_nIntermediateResult = _CommSendByte( Asc(StringMid($l_sCommand, $l_nCharIndex ,1)), 1)
                if ( $l_nIntermediateResult <> $COMMGDRIVER_SUCCESS) Then
                    MsgBox(0, "info", "nok")
                Else
;~                  MsgBox(0, "info", "ok")
                endif
                if ($l_nCharIndex <= $l_nCommandLength) then
                    sleep( $COMPORT_INTERCHARDELAY_MS )
                endif
                $l_nCharIndex = $l_nCharIndex + 1
            WEnd
            
            if ($l_bEnablePolling == 0) then
                sleep(5000)         
                $l_sReturnedResponse = _Commgetstring()
            Else
                for $l_nRetryCount = 1 to 100
                    ;sleep(10)          
                    $l_sReturnedResponse = $l_sReturnedResponse & _Commgetstring()
                next
            endif
            if (@error == 0) then
                msgbox (1, "info", "[" & $l_sCommand  & "] -> " & $l_sReturnedResponse )            
            Else
                msgbox (1, "info", "Error detected " & @error & "with [" & $l_sCommand  & "] -> " & $l_sReturnedResponse )          
            endif
        wend
        ; seems to kill all serial ports
        _CommClosePort()

Thanks

Bram

martin · October 10, 2008