Asserting the RTS signal for serial ports

Question

I've posted a few times, about asserting the DTR signal line for the serial
ports.
To start off with, i have now come to the realization that I was STUPIDLY
trying to set the wrong thing... I needed to set the RTS, not the DTR!!!
Most of the replies I got said to use the IN PORT and OUT PORT vi's, from
the advanced, memory/portI/O palette.
When i had a fiddle around with these, and looked them up in more depth, I
found a few things...
1. I have read a few times, that these are not portable, because of machine
dependancy... Can anyone tell me how portable they are? Such as, are they
fine for all Intel based architechure's, or what
2. I found that if I initialize the serial port, using the Serial Port
Init.vi, and then use
the Out Port.vi, to set the RTS, by addressing the
register at 0x2FC, for COM 2, the next thing I did, which was write to the
serial port, hung. When I highlighted execution, it was stuck in the Serial
Write.vi Can anybody tell me what I'm doing wrong?
Your help would be greatly appreciated!
Slade Squire
Programmer
Rectifier Technologies Pacific
Melbourne, Australia
[email protected]

Answer 1

You should read replies to your posts more carefully since Craig Graham have
pointed out that VI to use to assert RTS and DTR lines of a serial port. You
also should search this group for the RS485 and RTS/DTR topic; it is a
recurrent question and there are some pitfalls on toggling RS485 direction
in LabVIEW.
As for RTS flow control, you will see something only when the input buffer
of the serial port is full, in which case RTS is asserted to signal the
transmitter to pause transmission.
Jean-Pierre Drolet
"Slade Squire" a �crit dans le message de news:
[email protected]...
> Something else I forgot to mention....
>
> When I try and set RTS in the flow control parameter of Serial Port
Init.vi,
> it doesn't do anything!
> Why?
> (I know it doesn't do anything, because I have an oscilliscope set up on
the
> end of the com cable, wired to the RTS pin)
>
> "Slade Squire" wrote in message
> news:[email protected]...
> > I've posted a few times, about asserting the DTR signal line for the
> serial
> > ports.
> > To start off with, i have now come to the realization that I was
STUPIDLY
> > trying to set the wrong thing... I needed to set the RTS, not the
DTR!!!
> >
> > Most of the replies I got said to use the IN PORT and OUT PORT vi's,
from
> > the advanced, memory/portI/O palette.
> >
> > When i had a fiddle around with these, and looked them up in more depth,
I
> > found a few things...
> >
> > 1. I have read a few times, that these are not portable, because of
> machine
> > dependancy... Can anyone tell me how portable they are? Such as, are
they
> > fine for all Intel based architechure's, or what
> >
> > 2. I found that if I initialize the serial port, using the Serial Port
> > Init.vi, and then use the Out Port.vi, to set the RTS, by addressing the
> > register at 0x2FC, for COM 2, the next thing I did, which was write to
the
> > serial port, hung. When I highlighted execution, it was stuck in the
> Serial
> > Write.vi Can anybody tell me what I'm doing wrong?
> >
> > Your help would be greatly appreciated!
> >
> > --
> > Slade Squire
> > Programmer
> > Rectifier Technologies Pacific
> > Melbourne, Australia
> > [email protected]
> >
> >
> >
>
>
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