OT : different Rx and Tx baud rate on same port
Hi,
I am looking for current serial adapters that support split baud rates.
That is different input and output baud rate.
Grateful for suggestions!
kind regards,
Björn
Björn,
If you can't find a black box that does this, just use two serial ports: Rx from one and the Tx from the other. On the software side it means opening two devices, but that shouldn't be hard to handle.
Note bb-elec.com used to make a cute 4-port serial concentrator that would allow you to configure different baud rates in/out, but I see that's no longer a current product.
Of course you could do all this with a micro or SBC, but I assume you're looking for a turn-key device rather than a homebrew project.
/tvb
----- Original Message -----
From: ""Björn"" bg@lysator.liu.se
To: time-nuts@febo.com
Sent: Friday, December 06, 2013 4:14 PM
Subject: [time-nuts] OT : different Rx and Tx baud rate on same port
Hi,
I am looking for current serial adapters that support split baud rates.
That is different input and output baud rate.
Grateful for suggestions!
kind regards,
Björn
Hi,
I am looking for current serial adapters that support split baud rates.
That is different input and output baud rate.
Grateful for suggestions!
kind regards,
Björn
time-nuts mailing list -- time-nuts@febo.com
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Björn;
What platforms (HW and OS) are we considering? If I were writing the
software, I'd seriously consider using two ports.
JimT
Sent from my galaxy (Nexus).
On Dec 6, 2013 9:33 PM, Björn bg@lysator.liu.se wrote:
Hi,
I am looking for current serial adapters that support split baud rates.
That is different input and output baud rate.
Grateful for suggestions!
kind regards,
Björn
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
The posix C library supports this. http://linux.die.net/man/3/tcsetattr
with the cfsetispeed and cfsetospeed functions.
We do something similar to synthesize 1-wire protocol with the serial port
by switching between baud rates to change from data to reset pulses. It
works pretty well depending on how well your usb-serial convertor supports
corner cases.
Of course this requires writing your own software.
Paul Alfille
On Fri, Dec 6, 2013 at 11:48 PM, James Tucker james.d.tucker@gmail.comwrote:
Björn;
What platforms (HW and OS) are we considering? If I were writing the
software, I'd seriously consider using two ports.
JimT
Sent from my galaxy (Nexus).
On Dec 6, 2013 9:33 PM, Björn bg@lysator.liu.se wrote:
Hi,
I am looking for current serial adapters that support split baud rates.
That is different input and output baud rate.
Grateful for suggestions!
kind regards,
Björn
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
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Tom, Bob & James, (will answer in one response, to save some bandwidth)
I have a GPS receiver that is hard configured at 19200baud one way, and
76800baud the other.
The most convinient would be a USB serial adapter, but ExpressCard or
PC-CARD is also ok. PCI/PCIE is better than nothing.
HW is a laptop. Preferably a modern one. But one with PCMCIA is also ok.
I have a (binary only) windows program that I need to run. Windows version
either XP or preferably win7. But I am interested in running the adapter
in linux also.
In Linux I can arrange with combining two serial ports, since I have the
source. In MSWindows I do not have that luxuary.
Have seen reference to the bb-elec stuff. The closest I found now is
http://www.bb-elec.com/Products/Datasheets/232brc_0812DSds.pdf
which convert baud rates, but I think not in the way I wish.
I have looked but not fully digested if the advanced async/sync serial
adapters can do split baud rates.
http://www.commtech-fastcom.com/data_sheets/sab82532.pdf
It seems there was a time in the distant past where this was more common.
" Setting the input baud rate to zero was a mechanism to allow for
split baud rates. Clarifications in this volume of IEEE Std
1003.1-2001 have made it possible to determine whether split
rates are supported and to support them without having to treat
zero as a special case."
http://manpages.ubuntu.com/manpages/hardy/man3/cfgetispeed.3posix.html
Here is an (obsolete, but with documentation from 2009 its not ancient)
serial controller from Exar
"The Independent TX/RX Baud Rate Generator feature allows the transmitter
and receiver to operate at different baud rates."
http://www.exar.com/connectivity/uart-and-bridging-solutions/8-bit-vlio-uarts/xr16m680
Looking at the "stty" unix command. It seems clear that split baud rates
has been supported at one time.
http://www.openbsd.org/cgi-bin/man.cgi?query=stty&sektion=1
"ispeed number
Set terminal input baud rate to the number given, if
possible. If the input baud rate is set to zero, the input
baud rate is set to the value of the output baud rate.
ospeed number
Set terminal output baud rate to the number given, if
possible. If the output baud rate is set to zero, modem
control is no longer asserted.
speed number
This sets both ispeed and ospeed to number."
With this much hinting, I was hoping there was still some hardware out
there supporting split baud rates.
kind regards,
Björn
Björn,
If you can't find a black box that does this, just use two serial ports:
Rx from one and the Tx from the other. On the software side it means
opening two devices, but that shouldn't be hard to handle.
Note bb-elec.com used to make a cute 4-port serial concentrator that would
allow you to configure different baud rates in/out, but I see that's no
longer a current product.
Of course you could do all this with a micro or SBC, but I assume you're
looking for a turn-key device rather than a homebrew project.
/tvb
----- Original Message -----
From: ""Björn"" bg@lysator.liu.se
To: time-nuts@febo.com
Sent: Friday, December 06, 2013 4:14 PM
Subject: [time-nuts] OT : different Rx and Tx baud rate on same port
Hi,
I am looking for current serial adapters that support split baud rates.
That is different input and output baud rate.
Grateful for suggestions!
kind regards,
Björn
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Paul,
The posix C library supports this. http://linux.die.net/man/3/tcsetattr
with the cfsetispeed and cfsetospeed functions.
Yes, but do the serial device drivers (still) support it? Is there
hardware supporting it?
--
Björn
Here is a snippet of code from a program in "C" I have running on Linux. Notice that I had to set both the input and output baud rates. After looking around on the web, it seems to be a matter of whether the hardware will support split baud rate. So, essentially, code it and try it.
cfsetospeed(&tioPLL,B4800); // 4800 baud
cfsetispeed(&tioPLL,B4800); // 4800 baud
tcsetattr(ttyPLL,TCSANOW,&tioPLL);
Bob