Dontronics USB-232 converter

T

The Real Andy

Guest
OK, I have finally found a USB-232 converter which doesn't crash my
PC. Whilst being a fairly good device, I still have found a few
problems which others may have experienced.

The main problem is that I am dealing with serial devices that
continuously transmit data. With the FTDI chip, if to much data is
received the device or the driver appears to hang. I am guessing it is
the device as the RX led stops blinking.

So, what I am guessing is that the FTDI chip has a FIFO buffer that
once full stops receiving data. I am also guessing that the supplied
driver does not retrieve that data if it is not requested by an
application. It seems that once the buffer is full, the com port
cannot be opened. What I have found is that if I try re-opening the
com port straight away then the second time is successful. I can work
around that in my code, but I would prefer not to.

Has anyone seen this before? If so is there an easy work around? I
think the use of a circular buffer in the driver may solve the
problem. I would consider writing a new driver but alas, I have no
time at this stage.


The other problem is that if I restart the PC, and leave the serial
device connected, WinXP thinks it has found a new serial mouse. I did
note some info on the FTDI site that may be useful, but have not
really looked into it a great deal. I was hoping that someone else may
have seen these problems before. The latter issue seems to occur in
any USB-232 convertor that I have used.

Regards:

Andy
 
"The Real Andy" <a.pearson@wayit_dot_com_dot_au_remove_the_obvious_to_reply>
wrote in message news:gb0v70ddmlk230vlc98379bmeapd29mpmn@4ax.com...
OK, I have finally found a USB-232 converter which doesn't crash my
PC. Whilst being a fairly good device, I still have found a few
problems which others may have experienced.

The main problem is that I am dealing with serial devices that
continuously transmit data. With the FTDI chip, if to much data is
received the device or the driver appears to hang. I am guessing it is
the device as the RX led stops blinking.

So, what I am guessing is that the FTDI chip has a FIFO buffer that
once full stops receiving data. I am also guessing that the supplied
driver does not retrieve that data if it is not requested by an
application. It seems that once the buffer is full, the com port
cannot be opened. What I have found is that if I try re-opening the
com port straight away then the second time is successful. I can work
around that in my code, but I would prefer not to.

Has anyone seen this before? If so is there an easy work around? I
think the use of a circular buffer in the driver may solve the
problem. I would consider writing a new driver but alas, I have no
time at this stage.


The other problem is that if I restart the PC, and leave the serial
device connected, WinXP thinks it has found a new serial mouse. I did
note some info on the FTDI site that may be useful, but have not
really looked into it a great deal. I was hoping that someone else may
have seen these problems before. The latter issue seems to occur in
any USB-232 convertor that I have used.

Regards:

Andy
Click to expand...
Andy,
Try going into the port settings and turn off the FIFO buffers as
these are only compatible with a 16550 UART. Your USB-232 converter may or
may not be 16550 compatible.

Regards
Giles
 
The Real Andy wrote:
OK, I have finally found a USB-232 converter which doesn't crash my
PC. Whilst being a fairly good device, I still have found a few
problems which others may have experienced.

The main problem is that I am dealing with serial devices that
continuously transmit data. With the FTDI chip, if to much data is
received the device or the driver appears to hang. I am guessing it is
the device as the RX led stops blinking.

So, what I am guessing is that the FTDI chip has a FIFO buffer that
once full stops receiving data. I am also guessing that the supplied
driver does not retrieve that data if it is not requested by an
application. It seems that once the buffer is full, the com port
cannot be opened. What I have found is that if I try re-opening the
com port straight away then the second time is successful. I can work
around that in my code, but I would prefer not to.

Has anyone seen this before? If so is there an easy work around? I
think the use of a circular buffer in the driver may solve the
problem. I would consider writing a new driver but alas, I have no
time at this stage.

The other problem is that if I restart the PC, and leave the serial
device connected, WinXP thinks it has found a new serial mouse. I did
note some info on the FTDI site that may be useful, but have not
really looked into it a great deal. I was hoping that someone else may
have seen these problems before. The latter issue seems to occur in
any USB-232 convertor that I have used.
Click to expand...

I've have identical effects with XP and an U232-9 usb/rs232 converter
from Jaycar.
The only workaround for me is to disconnect or stop the RS232 data
stream before plugging in the converter or starting XP.
 
On Sat, 17 Apr 2004 05:57:36 +1000, MC <mc@nonexistant.place> wrote:


I've have identical effects with XP and an U232-9 usb/rs232 converter
from Jaycar.
The only workaround for me is to disconnect or stop the RS232 data
stream before plugging in the converter or starting XP.
Click to expand...
That's not an option for me as it is going to an industrial site,
where power goes up and down quite frequently. I might have to
completly rethink this issue to exlude USB. It would be nice though,
as I can send a whole heap of peripherals down one line very cheaply.
 
On Sat, 17 Apr 2004 10:55:40 +1000, The Real Andy
<a.pearson@wayit_dot_com_dot_au_remove_the_obvious_to_reply> wrote:

On Sat, 17 Apr 2004 05:57:36 +1000, MC <mc@nonexistant.place> wrote:




I've have identical effects with XP and an U232-9 usb/rs232 converter
from Jaycar.
The only workaround for me is to disconnect or stop the RS232 data
stream before plugging in the converter or starting XP.

That's not an option for me as it is going to an industrial site,
where power goes up and down quite frequently. I might have to
completly rethink this issue to exlude USB. It would be nice though,
as I can send a whole heap of peripherals down one line very cheaply.
Click to expand...
The problem you are having seems very similar to my experience with
the Belkin USB->Serial adapter. After a few minutes of continuous
operation the drivers hang and never return.

The only USB->Serial converter that I would recommend is the
Edgeport/1 from IO Networks. This product is aimed more at commercial
applications than as a consumer product. With the windows XP driver I
used about 18months ago it was about 98% reliable. But very
occaisionally gave error messages when the PC was shut down.

regards,
Johnny.
 
The Real Andy wrote:
On Sat, 17 Apr 2004 05:57:36 +1000, MC <mc@nonexistant.place> wrote:



I've have identical effects with XP and an U232-9 usb/rs232 converter
from Jaycar.
The only workaround for me is to disconnect or stop the RS232 data
stream before plugging in the converter or starting XP.

That's not an option for me as it is going to an industrial site,
where power goes up and down quite frequently. I might have to
completly rethink this issue to exlude USB. It would be nice though,
as I can send a whole heap of peripherals down one line very cheaply.
Click to expand...
Is this for a laptop or a 'normal' PC ?
ie. do you have spare PCI slots for (say) a multiport serial card ?

USB generally doesn't go too far, but it does neaten the
cabling rat-nest a little.
 
On Sat, 17 Apr 2004 11:22:29 +1000, MC <mc@nonexistant.place> wrote:

The Real Andy wrote:

On Sat, 17 Apr 2004 05:57:36 +1000, MC <mc@nonexistant.place> wrote:



I've have identical effects with XP and an U232-9 usb/rs232 converter
from Jaycar.
The only workaround for me is to disconnect or stop the RS232 data
stream before plugging in the converter or starting XP.

That's not an option for me as it is going to an industrial site,
where power goes up and down quite frequently. I might have to
completly rethink this issue to exlude USB. It would be nice though,
as I can send a whole heap of peripherals down one line very cheaply.

Is this for a laptop or a 'normal' PC ?
ie. do you have spare PCI slots for (say) a multiport serial card ?

USB generally doesn't go too far, but it does neaten the
cabling rat-nest a little.
Click to expand...
Its off an industrial PC. I could use serial cards, but I prefer not
to. I am currently running 2 serial ports and 1 parallel port with a
USB extender. If I have to, i will run a seperate SBC via ethernet to
where the perhiperals are situated.
 
The Real Andy wrote:

That's not an option for me as it is going to an industrial site,
where power goes up and down quite frequently. I might have to
completly rethink this issue to exlude USB. It would be nice though,
as I can send a whole heap of peripherals down one line very cheaply.
Click to expand...
have a chat to keith.dingwall AT ftdichip.com
Keith Dingwall
Applications Engineer
FTDI Support

He will be able to give you all the technical info available on these
units.
Keith knows them pretty well.

Cheers Don...


--
Don McKenzie
E-Mail Contact Page: http://www.e-dotcom.com/ecp.php?un=Dontronics

USB to RS232 Converter that works http://www.dontronics.com/usb_232.html
Don's Free Guide To Spam Reduction http://www.e-dotcom.com/spam_exp.php
 
On Sat, 17 Apr 2004 18:56:17 +1000, Don McKenzie <look@my.sig.com>
wrote:

The Real Andy wrote:

That's not an option for me as it is going to an industrial site,
where power goes up and down quite frequently. I might have to
completly rethink this issue to exlude USB. It would be nice though,
as I can send a whole heap of peripherals down one line very cheaply.

have a chat to keith.dingwall AT ftdichip.com
Keith Dingwall
Applications Engineer
FTDI Support

He will be able to give you all the technical info available on these
units.
Keith knows them pretty well.

Cheers Don...
Click to expand...
Thanks, will do.
 
For industrial PC work, I would recommend the "real" serial cards over the
USB virtual serial port with adapter.


1. USB on Windows is still not quite solid.

2. The serial card is fantastically solid under all versions of Windows.
Because the cards are hardware compatible, the standard Windows driver works
well.

3. I have pumped so much data through the serial port under all 32 bit
versions of Windows on all sorts of computers in Australia and overseas with
total success.

4. With USB you have to get into the Windows Driver Support nightmare. If
drivers don't work on certain Windows versions and the manufacturer doesn't
have new drivers, you have to find a different USB-RS232 adapter. Its
always a potential problem. You don't have control, and so you are subject
to a risk - and risk management is engineering.

5. You want a build and walk away solution. If something dies in years to
come, you will have to open up the whole can of worms again.


regards
Roger


"The Real Andy" <a.pearson@wayit_dot_com_dot_au_remove_the_obvious_to_reply>
wrote in message news:kjl1805rnharil8l4b62lmaekrarfe31t2@4ax.com...
On Sat, 17 Apr 2004 11:22:29 +1000, MC <mc@nonexistant.place> wrote:

The Real Andy wrote:

Its off an industrial PC. I could use serial cards, but I prefer not
to. I am currently running 2 serial ports and 1 parallel port with a
USB extender. If I have to, i will run a seperate SBC via ethernet to
where the perhiperals are situated.
Click to expand...
 
"The Real Andy" <a.pearson@wayit_dot_com_dot_au_remove_the_obvious_to_reply>
wrote in message news:6gq3805htv2frgb2khdsblohvt9r49p674@4ax.com...
On Sat, 17 Apr 2004 18:56:17 +1000, Don McKenzie <look@my.sig.com
wrote:

The Real Andy wrote:

That's not an option for me as it is going to an industrial site,
where power goes up and down quite frequently. I might have to
completly rethink this issue to exlude USB. It would be nice though,
as I can send a whole heap of peripherals down one line very
cheaply.
Click to expand...
What about using Can ?

http://www.canopenbook.com/

The lawicel can to rs232 adaptor is handy for getting data
into a pc.PC sees it as a serial port.
http://www.can232.com/
http://www.dontronics.com/candip.html scroll down

may even be able to use it to go from can to ethernet
by connecting up to something like one of the www.edtp.com board
or other ethernet micro boards.

Other possibilities would be RS422 and RS485.
http://www.dontronics.com/usb_485.html

Alex
 
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