Viewsonic V37 Serial Port

I'm using the freebie Viewsonic V37 for connecting to a serial device. I'm
using a serial cable that I bought from Viewsonic and I've upgraded the OS
to PPC2003.

The problem I'm having is, I believe, that the V37's serial port is not
capable of fast simultaneous send and receive. I could be wrong about that,
but that is my best guess after hours of testing. I have a simple loopback
echo device, which ties RX and TX together, such that everything the V37
sends, it should receive. When using this, I receive no characters. When I
connect it to the PC I receive everything the PC sends and the PC receives
everything I send. I've even put a scope trace on the serial port while
sending and receiving to my actual slave device (a serial to 1-Wire adapter,
connected through a null-modem). I can see my slave device responding on
the scope, but the PPC does not receive the data. Even taking a wire and
shorting out pins 2 & 3 (RX and TX) on the V37 serial cable doesn't work,
even though that should loopback everything it sends.

I rolled my own serial port code on the device, but I've also tried the
OpenNETCF.io.serial stuff as well as someone else's CFSerial lib.

If anyone else has a V37 and a serial cable, I'd appreciate know if this
works for you. Download the OpenNETCF SerialSharp example and stick a wire
into pins 2 & 3 of your serial connector. See if you get an echo back of
every character you send.

Thanks,

Scott Hughes
Engineer - Maxim/Dallas Semiconductor

Scott
Fri May 28 12:49:31 CDT 2004

I see that their are serial devices (GPS) available which claim to be
compatible with the Viewsonic V37, so there must be something I'm missing.
Maybe an undocumented kernel call:
void viewsonic_enableFullDuplexSerial(BOOL); ???

Has anyone had success using the Viewsonic V37's serial port with a slave
device?

Scott Hughes

Floyd
Fri May 28 13:05:30 CDT 2004

Scott,
I don't know about the V37, but I can use my V36 port to talk to my GPS,
LCD, terminal, etc. I haven't been able to find my loopback to test the
full-duplex, but I'm pretty sure that worked also. I'm using the TransPort
beta from ComponentScience, but the OpenNet stuff worked too.

--
Floyd Burger


"Scott Hughes" <shughes aht dalsemi daut com> wrote in message
news:%23X6hbYCREHA.3720@TK2MSFTNGP09.phx.gbl...
> I'm using the freebie Viewsonic V37 for connecting to a serial device.
I'm
> using a serial cable that I bought from Viewsonic and I've upgraded the OS
> to PPC2003.
>
> The problem I'm having is, I believe, that the V37's serial port is not
> capable of fast simultaneous send and receive. I could be wrong about
that,
> but that is my best guess after hours of testing. I have a simple
loopback
> echo device, which ties RX and TX together, such that everything the V37
> sends, it should receive. When using this, I receive no characters. When
I
> connect it to the PC I receive everything the PC sends and the PC receives
> everything I send. I've even put a scope trace on the serial port while
> sending and receiving to my actual slave device (a serial to 1-Wire
adapter,
> connected through a null-modem). I can see my slave device responding on
> the scope, but the PPC does not receive the data. Even taking a wire and
> shorting out pins 2 & 3 (RX and TX) on the V37 serial cable doesn't work,
> even though that should loopback everything it sends.
>
> I rolled my own serial port code on the device, but I've also tried the
> OpenNETCF.io.serial stuff as well as someone else's CFSerial lib.
>
> If anyone else has a V37 and a serial cable, I'd appreciate know if this
> works for you. Download the OpenNETCF SerialSharp example and stick a
wire
> into pins 2 & 3 of your serial connector. See if you get an echo back of
> every character you send.
>
> Thanks,
>
> Scott Hughes
> Engineer - Maxim/Dallas Semiconductor
>
>

Dick
Tue Jun 01 09:35:56 CDT 2004

Hi,

I haven't tried the V37 yet. I have one "ready to go," but I'm involved in
another project that I need to finish first (and I have to order the cable).
Did you try it with CFSerialIO from my homepage? I haven't had any trouble
with other hardware, regardless of speed. No data are missed, and I cannot
think of any real reason that any might be.

Dick

--
Richard Grier (Microsoft Visual Basic MVP)

See www.hardandsoftware.net for contact information.

Author of Visual Basic Programmer's Guide to Serial Communications, 3rd
Edition ISBN 1-890422-27-4 (391 pages) published February 2002.

Scott
Tue Jun 01 11:44:11 CDT 2004

Dick,

> Did you try it with CFSerialIO from my homepage? I haven't had any
trouble
> with other hardware, regardless of speed. No data are missed, and I
cannot
> think of any real reason that any might be.

Yes, I've tried CFSerialIO, with your test app, and got the same result..
Using a loopback, I get no bytes back on the serial port. Send data from
the PC and I receive every byte.

I agree, that I can't think of any reason that data should be missed.
Unless, there is something bizarre with my own hardware. It looks like a
half-duplex issue, but I can't imagine that that's the case, as lots of
serial stuff wouldn't work. For example, I can sync the device with my PC.
I'm not sure how much delay or retries are in the ActiveSync protocol, such
that it could still recover even when a byte was missed..

I sent an email to viewsonic's tech support, but I'm not expecting a good
answer. Their knowledge base is targeted towards the "What is a USB cable?"
questions. I don't know how to find technical documentation or real
developer's assistance for the V37.

btw, I tried my own serial port code on an older HP Jornada that someone
lent me, and it worked fine "out-of-the-box" with my loopback echo device
with and without the null-modem in-between. So, I've ruled out my software
and every piece of hardware besides the V37 and its serial cable.

Scott

ybradette
Wed Jun 02 11:32:09 CDT 2004

Not to go off topic but I am also working on a v37 serial project.

Just wondering if anyone has the v37's connector pinout?

I tried..tried...tried and can't dig it up anywhere.

Much appreciated!

Scott
Mon Jun 07 18:03:27 CDT 2004

I'd be interested in this, as well as any other technical documentation on
the V37, that you could dig up.

Scott

"ybradette" <ybradette@yahoo.ca> wrote in message
news:0ddc96ff1e178d75c9da4c80639f4f41@localhost.talkaboutcomputing.com...
> Not to go off topic but I am also working on a v37 serial project.
>
> Just wondering if anyone has the v37's connector pinout?
>
> I tried..tried...tried and can't dig it up anywhere.
>
> Much appreciated!
>

Dick
Thu Jun 10 15:47:43 CDT 2004

Hi,

I have tried the internal serial port on my Viewsonic V37. It works fine.
Make sure that you have both of the properties:
.CTSHandshaking = False

and
.XonXoffHandshaking = False

(if using CFSerialIO from my homepage). I haven't tested this with
OpenNETCF Serial, but I have no reason to suspect a problem there, either.

If you still are having trouble, post some code that duplicates the problem.

Dick
--
Richard Grier (Microsoft Visual Basic MVP)

See www.hardandsoftware.net for contact information.

Author of Visual Basic Programmer's Guide to Serial Communications, 3rd
Edition ISBN 1-890422-27-4 (391 pages) published February 2002.

Scott
Wed Jun 16 10:43:31 CDT 2004

Hey, thanks for the follow-up.

Did you try it with a loopback echo? Just sticking a wire in between pins 2
& 3 should do it.

Scott


"Dick Grier" <dick_grierNOSPAM@msn.com> wrote in message
news:uiobnwyTEHA.2844@TK2MSFTNGP12.phx.gbl...
> Hi,
>
> I have tried the internal serial port on my Viewsonic V37. It works fine.
> Make sure that you have both of the properties:
> .CTSHandshaking = False
>
> and
> .XonXoffHandshaking = False
>
> (if using CFSerialIO from my homepage). I haven't tested this with
> OpenNETCF Serial, but I have no reason to suspect a problem there, either.
>
> If you still are having trouble, post some code that duplicates the
problem.
>
> Dick
> --
> Richard Grier (Microsoft Visual Basic MVP)
>
> See www.hardandsoftware.net for contact information.
>
> Author of Visual Basic Programmer's Guide to Serial Communications, 3rd
> Edition ISBN 1-890422-27-4 (391 pages) published February 2002.
>
>

Scott
Mon Jun 21 12:08:40 CDT 2004

And another follow-up question.. What version of the PPC OS are you using?
I'm using PPC 2003. Unfortunately, I don't have a backup of the original OS
to try.

Scott


"Scott Hughes" <shughes aht dalsemi daut com> wrote in message
news:u%23dq9$6UEHA.2484@TK2MSFTNGP11.phx.gbl...
> Hey, thanks for the follow-up.
>
> Did you try it with a loopback echo? Just sticking a wire in between pins
2
> & 3 should do it.
>
> Scott
>
>
> "Dick Grier" <dick_grierNOSPAM@msn.com> wrote in message
> news:uiobnwyTEHA.2844@TK2MSFTNGP12.phx.gbl...
> > Hi,
> >
> > I have tried the internal serial port on my Viewsonic V37. It works
fine.
> > Make sure that you have both of the properties:
> > .CTSHandshaking = False
> >
> > and
> > .XonXoffHandshaking = False
> >
> > (if using CFSerialIO from my homepage). I haven't tested this with
> > OpenNETCF Serial, but I have no reason to suspect a problem there,
either.
> >
> > If you still are having trouble, post some code that duplicates the
> problem.
> >
> > Dick
> > --
> > Richard Grier (Microsoft Visual Basic MVP)
> >
> > See www.hardandsoftware.net for contact information.
> >
> > Author of Visual Basic Programmer's Guide to Serial Communications, 3rd
> > Edition ISBN 1-890422-27-4 (391 pages) published February 2002.
> >
> >
>
>