Re: [Ftdi-usb-sio-devel] Long delay between break signal and first data bytes

[Bill R. <bil...@gm...>]

Did you try tcsendbreak with a set value rather than 0?

By default it may wait up to 500ms even though data isn't being sent for
500ms

You can check it with strace -T yourTestProgram  - you'll see the duration
of tcsendbreak in <>'s in the output.



On Sat, Oct 25, 2008 at 3:38 AM, Peter Künnemann <pet...@we...>wrote:

> Hi,
> I am using an FTDI device on a linux system (2.6.24-21) USB Data are:
>
> FTDZIG54, TTL232R
>
> I am having some trouble to get tcsendbreak() working. I am expecting a
> break level for some milliseconds on the TX line followed by the data.
>
> The C code looks as follows:
> //
> int sync=0x55;
>
> tcsendbreak(handle,0)
> write(handle,&sync,1)
> ...
> //
> When I connect a scope to the tx line I can see something like:
>
> ~~~~.__,~~~~~~~~~~~~,_|||||
>     A break signal
>         some 500ms delay
>                     the data beeing sent
>
> I wonder how I would be able to send a break, immediately followed by my
> data. The problem is that other devices on the line do not expect such a
> long delay following the break signal.
>
> Any help regarding breaks and general serial programming for ftdi
> devices under linux would be very much appreciated.
> I have scaned the internet for some help but nothing apropriate was found
>
> regards, Peter
>
>
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's
> challenge
> Build the coolest Linux based applications with Moblin SDK & win great
> prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Ftdi-usb-sio-devel mailing list
> Ftd...@li...
> https://lists.sourceforge.net/lists/listinfo/ftdi-usb-sio-devel
>