Dear All,
I have a mini driver for a usb device. My driver works well with the
usb cable connecting the usb ports at both ends…now if my device
(Controller) side is a Serial port and i use a Serial to USB Convertor and
plug into the usb port on my pc…my driver starts mal-functioning…
Does this have anything to do with the convertor in between?
TIA
Sesha.
** Reply to message from “Seshagiri Babu” on
Thu, 16 May 2002 03:41:44 -0400
> I have a mini driver for a usb device. My driver works well with the
> usb cable connecting the usb ports at both ends…now if my device
> (Controller) side is a Serial port and i use a Serial to USB Convertor and
> plug into the usb port on my pc…my driver starts mal-functioning…
>
> Does this have anything to do with the convertor in between?
Hmm… it just might :-). Are you sure that you understand what you have
there? I’ve never seen a Serial-to-USB converter. All the devices I’ve seen
are USB-to-Serial. In other words, you can get serial ports across a USB
connection, but not a USB connection through a serial port.
If there actually is a Serial-to-USB device floating around out there, I’d
like to hear about it, if only to ask the vendor why they bothered.
Sincerely,
Chris Myers
Senior Project Engineer
Quatech, Inc.
Dear All,
We have a device which is connected at the USB port of the pc using
serial to USB converter, the other end being Serial. Now i use an
application to read from the COM port enumerated by the converter driver.
But the Read request waits indefinitely though theres’ some data on the
device
Any hints on this behaviour…
cheers
Sesha.
Hello Sesha,
Did you try calling GetCommstatus function from the application ?
That would shed some light on what’s happening in the USB to serial
converter
driver.
With regards
D.Nagarajan.
-----Original Message-----
From: Seshagiri Babu [mailto:xxxxx@bla.satyam.com]
Sent: Monday, June 03, 2002 7:11 PM
To: NT Developers Interest List
Subject: [ntdev] serial to usb converter
Dear All,
We have a device which is connected at the USB port of the pc using
serial to USB converter, the other end being Serial. Now i use an
application to read from the COM port enumerated by the converter driver.
But the Read request waits indefinitely though theres’ some data on the
device
Any hints on this behaviour…
cheers
Sesha.
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Is the data enough to fulfill the Read request?
Did you set a timeout, or an InterCharacter timeout?
If you issue a Read for 1023 bytes of data and there is only 512 available,
then the request will wait indefinitely for the other 512 bytes of data?
“Seshagiri Babu” wrote in message
news:xxxxx@ntdev…
>
> Dear All,
> We have a device which is connected at the USB port of the pc using
> serial to USB converter, the other end being Serial. Now i use an
> application to read from the COM port enumerated by the converter driver.
> But the Read request waits indefinitely though theres’ some data on the
> device
> Any hints on this behaviour…
>
> cheers
> Sesha.
>
>
I have set the timeouts properly. And i’m requesting for a single byte. I
have tested the same code using a serial cable connected to serial ports
at both ends (device and the host). The problem comes only when i use the
serial to usb converter and the driver for this enumerates a
(virtual)COM5.
One more doubt i get is, can i use this VIRTUAL COM5 like other
COM(1-4) ports on my pc or do i need to do something more to talk to this
virtual port…
cheers
Sesha.
Is the data enough to fulfill the Read request?
Did you set a timeout, or an InterCharacter timeout?
If you issue a Read for 1023 bytes of data and there is only 512 available,
then the request will wait indefinitely for the other 512 bytes of data?“Seshagiri Babu” wrote in message
> news:xxxxx@ntdev…
> >
> > Dear All,
> > We have a device which is connected at the USB port of the pc using
> > serial to USB converter, the other end being Serial. Now i use an
> > application to read from the COM port enumerated by the converter driver.
> > But the Read request waits indefinitely though theres’ some data on the
> > device
> > Any hints on this behaviour…
> >
> > cheers
> > Sesha.
> >
> >