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microsoft.public.win32.programmer.kernel: Re: RS232: How to find

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microsoft.public.win32.programmer.kernel: Re: RS232: How to find out last character sent
Re: RS232: How to find out last character sent
Source:
http://www.techв€’archive.net/Archive/Development/microsoft.public.win32.programmer.kernel/2004в€’03/0752.html
From: Jojo (mfgjojo_at_gmx.de)
Date: 03/25/04
Date: Thu, 25 Mar 2004 10:32:14 +0100
> Seems like RTS_CONTROL_TOGGLE is what you need.
Yes, but I already do :)
The problem is that the toggle isnВґt fast enough.
> You need to be more specific about your control protocol
> or flow control requirement, though.
Whats unclear?
The RTS should raise before any data is going out and lower if all data has
been sent. But as said the RTS is about 15ms too long in up state.
More specific:
There are three interfaces between the pc and the device in the following
order: RS232, RS485, RS232. Because the RS485 is only half duplex, what
means that you can only receive or transmit at the same time you need to
switch to either receive or transmit. This switching is done with the RTS
Pin. If you have a lot of receive/transmit switches and you always have to
wait at least 15ms, the waiting times and therefore the whole communication
time increases drastically. Those 15ms are independently from the used
baudrate.
Thanks,
Joachim
"Isaac Chen" <isaachen@deleteв€’this.pchome.com.tw> schrieb im Newsbeitrag
news:O0OplbVEEHA.3788@TK2MSFTNGP10.phx.gbl...
> Seems like RTS_CONTROL_TOGGLE is what you need.
> You need to be more specific about your control protocol
> or flow control requirement, though.
>
> Isaac
>
> "Jojo" <mfgjojo@gmx.de> wrote in message
> news:c3pvtu$aqb$07$1@news.tв€’online.com...
> > Hello NG.
> > I want to send Data over RS232 to a device. Because of the distance the
> > RS232 is convertet to RS484. The direction is selected through RTS.
> > The Problem is that when I use RTS_CONTROL_HANDSHAKE the time takes too
> long
Re: RS232: How to find out last character sent
1
microsoft.public.win32.programmer.kernel: Re: RS232: How to find out last character sent
> > for the RTS Pin to low state. When I send a character the RTS goes high
> > state and after the characters are sent it takes about 15ms for the RTS
to
> > go low state. How can I prevent this? When I manually set the RTS to
high
>I
> > have to find out when the last character was sent so that I can lower
the
> > RTS. If I SetComTimeouts for the write the writefile returns a view ms
> > before all characters are really sent out.
>>
> > Thanks in advance,
> > Joachim
>>
>>
>
>
Re: RS232: How to find out last character sent
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