[Tcl-bugs] [ tcl-Bugs-656112 ] fconfigure -ttycontrol -mode problem

[<no...@so...>]

Bugs item #656112, was opened at 2002-12-18 21:53
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110894&aid=656112&group_id=10894

Category: 15. Commands A-H
Group: 8.4.1
Status: Open
Resolution: None
Priority: 5
Submitted By: Bob Parnass (parnass)
Assigned to: Donal K. Fellows (dkf)
Summary: fconfigure -ttycontrol -mode problem

Initial Comment:
The order of the arguments for the fconfigure command affects the outcome of the operation on WIndows 98.

I am using ActiveTcl 8.4.1 on both Linux and Windows 98 Second Edition
to run a program I wrote which uses the serial port.

My program communicates with the peripheral device ok on Linux but not Windows and I've traced the problem to fconfigure's new -ttycontrol option.

Using a simple line monitor, I can see that the RTS line
is not being held low on Windows when I execute this command:

                if { [catch {fconfigure $Sid \
                        -buffering none \
                        -translation binary \
                        -ttycontrol {DTR 1 RTS 0} \
                        -mode 4800,$parity,8,2 -blocking 1}] } \
                        {
                        set code -1
                        }

The RTS line is held low on Red Hat Linux 7.3.

I consulted with Rolf Schroedter, who responded:

"...Yes I see the problem. In Windows the -mode "string" interpretation resets all TTY states to their default values.
A simple workaround for you is to set the baud rate first and only then the
-ttycontrol. The following should work:

        fconfigure $Sid -buffering none -translation binary  -blocking 1 \
                -mode 4800,$parity,8,2 -ttycontrol {DTR 1 RTS 0}

Or even
        fconfigure $Sid -buffering none -translation binary  -blocking 1
        fconfigure $id  -mode 4800,$parity,8,2
        fconfigure $id -ttycontrol {DTR 1 RTS 0}

I'll have a look whether there is a way to correct this for future Tcl versions. On the other hand setting -mode is an elementary thing which reconfigures the UART hardware and should not be done during communication.  Thank you for pointing out the problem."





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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110894&aid=656112&group_id=10894