Initial setup issues (serial port bad?)...

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Joe

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Aug 23, 2008, 12:33:40 PM8/23/08
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OK, from reading some of the posts it sounds like I may have a bad
serial on my beagleboard, but I thought I'd run it past you to verify
that I am not missing something.

I am running my beagleboard from a 5v power supply. I have the serial
connected to my computer and I get a good display of the booting
process. My issue is that I am unable to issue any commands to the
beagleboard. Anything that I type using HyperTerm or TeraTerm doesn't
show up (it sits at the OMAP3 beagleboard.org # prompt).

So I tried multiple serial cables, multiple computers and multiple
terminal programs all with the same results. To me it seems that the
serial port is bad.

Am I missing something or is it a bad serial port?

Thanks.

Måns Rullgård

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Aug 23, 2008, 12:40:44 PM8/23/08
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Joe <joe.p...@gmail.com> writes:

You need to disable flow control.

--
Måns Rullgård
ma...@mansr.com

Joe

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Aug 23, 2008, 2:14:09 PM8/23/08
to Beagle Board
I appreciate the quick feedback. I had my programs setup in
accordance with the
directions on http://code.google.com/p/beagleboard/wiki/BeagleBootHwSetup.

I did verify the settings in both terminal programs and here is what I
get. After it
completes the boot process I am unable to issue any commands to the
beagleboard.

Here's the is beagleboard boot.

HyperTerm: COM2, 115200, 8 None, 1, None

Texas Instruments X-Loader 1.41
Skipped bad block at 0x100000
Starting OS Bootloader...


U-Boot 1.3.3-00035-gab55ae5-dirty (Jun 16 2008 - 17:35:22)

OMAP3530-GP rev 2, CPU-OPP2 L3-165MHz
OMAP3 Beagle Board + LPDDR/NAND
DRAM: 128 MB
NAND: 256 MiB
In: serial
Out: serial
Err: serial
Audio Tone on Speakers ... complete
OMAP3 beagleboard.org #

******************************
Tera Term COM1, 115200, 8, None, 1, None

Texas Instruments X-Loader 1.41
Skipped bad block at 0x100000
Starting OS Bootloader...


U-Boot 1.3.3-00035-gab55ae5-dirty (Jun 16 2008 - 17:35:22)

OMAP3530-GP rev 2, CPU-OPP2 L3-165MHz
OMAP3 Beagle Board + LPDDR/NAND
DRAM: 128 MB
NAND: 256 MiB
In: serial
Out: serial
Err: serial
Audio Tone on Speakers ... complete
OMAP3 beagleboard.org #

Any other thoughts?


On Aug 23, 12:40 pm, Måns Rullgård <m...@mansr.com> wrote:
> m...@mansr.com- Hide quoted text -
>
> - Show quoted text -

Jens Langwald

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Aug 23, 2008, 2:28:55 PM8/23/08
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What connection have you , do you use an usb to seriel adapter ?
Or a connection over  dsub ?

jens



2008/8/23 Joe <joe.p...@gmail.com>

Joe

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Aug 23, 2008, 2:32:43 PM8/23/08
to Beagle Board
I am using a Serial Null MODEM cable (DB9f to DB9f). I have verified
the pinouts.
Otherwise it all works as expected.

joe

On Aug 23, 2:28 pm, "Jens Langwald" <jens.langw...@googlemail.com>
wrote:
> What connection have you , do you use an usb to seriel adapter ?
> Or a connection over  dsub ?
>
> jens
>
> 2008/8/23 Joe <joe.plu...@gmail.com>
>
>
>
>
>
> > I appreciate the quick feedback.  I had my programs setup in
> > accordance with the
> > directions onhttp://code.google.com/p/beagleboard/wiki/BeagleBootHwSetup.
> > > - Show quoted text -- Hide quoted text -

Jens Langwald

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Aug 23, 2008, 2:34:32 PM8/23/08
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do you use a crossed cable ? or a one to one ?

2008/8/23 Joe <joe.p...@gmail.com>

Steve Sakoman

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Aug 23, 2008, 3:39:54 PM8/23/08
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> Any other thoughts?

There are two types of "standard" ribbon cable adaptors that go from
the 10 pin header to a db9.

IIRC, the "wrong" standard has the behaviour you are seeing. So you
might want to make sure that you have the right type.

Steve

John Beetem

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Aug 23, 2008, 4:07:51 PM8/23/08
to Beagle Board
I recommend checking the RS-232 input signal at BeagleBoard P9 pin 2
with a digital 'scope or an LED with suitable series resistor (start
with 1K), just to make sure a valid RS-232 bit stream is actually
coming from the PC.

If no RS-232 bit stream, see if RS-232 signal is present at the DB-9.
Check for broken wire in DB9 to IDC cable.

BeagleBoard only implements RS-232 signals RX, TX, and GND. Most PCs
are fine as long as you turn off flow control. However, your PC may
want to see DSR before it transmits to BeagleBoard and needs to have
DTR wrapped back to DSR.

Here's a useful experiment: disconnect BeagleBoard and jumper TX (DB9
pin 3) to RX (pin 2) at the end of your null modem cable. See if your
jumper echoes to your terminal emulator. If not, try jumpering DTR
(pin 4) to DSR (pin 6) and repeat test. You can also jumper RTS (pin
7) to CTS (pin 8) if you don't trust your software to have turned off
flow control.

Good luck!

Gerald Coley

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Aug 23, 2008, 7:08:02 PM8/23/08
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It does sound like the serial port is bad in one direction I suggest you enter an RMA and return the board for repair. We have had a few boards already with this issue.
 
Gerald

Dirk Behme

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Aug 24, 2008, 4:48:55 AM8/24/08
to Gerald Coley, beagl...@googlegroups.com
Gerald Coley wrote:
> It does sound like the serial port is bad in one direction I suggest you
> enter an RMA and return the board for repair. We have had a few boards
> already with this issue.

Any hint what's the root cause of this issue?

For an experienced developer it could be easier and cheaper if this
could be fixed, e.g. with a soldering iron, instead of sending the
board back, e.g. from Europe.

Thanks

Dirk

> On Sat, Aug 23, 2008 at 11:33 AM, Joe <joe.p...@gmail.com
> <mailto:joe.p...@gmail.com>> wrote:
>
>
> OK, from reading some of the posts it sounds like I may have a bad
> serial on my beagleboard, but I thought I'd run it past you to verify
> that I am not missing something.
>
> I am running my beagleboard from a 5v power supply. I have the serial
> connected to my computer and I get a good display of the booting
> process. My issue is that I am unable to issue any commands to the
> beagleboard. Anything that I type using HyperTerm or TeraTerm doesn't
> show up (it sits at the OMAP3 beagleboard.org

> <http://beagleboard.org/> # prompt).

Gerald Coley

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Aug 25, 2008, 4:59:50 PM8/25/08
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Cross, also known as null modem.Think of it this way. The BeagleBaord and PC are wired the same and have the same exact pinouts for TX and RX..
 
Gerald

Olivier Singla

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Sep 3, 2008, 4:03:06 PM9/3/08
to Beagle Board
Gerald,

Just got my beagle board from Digikey.
I have the very same issue as described here:
rs232 working only in one direction (beagle->pc).
I had it working once (pc->beagle). Also a few times I had garbage
characters
while typing. Now I have nothing, even after many power cycles.
Is there a way to avoid a RMA?

Thanks,
~Olivier

On Aug 23, 7:08 pm, "Gerald Coley" <ger...@beagleboard.org> wrote:
> It does sound like the serial port is bad in one direction I suggest you
> enter an RMA and return the board for repair. We have had a few boards
> already with this issue.
>
> Gerald
>

Gerald Coley

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Sep 3, 2008, 8:16:50 PM9/3/08
to beagl...@googlegroups.com
Well, if you can replace U9, then you can avoid an RMA. It is very tough to do. Then you will need to burn it in and then it could fial agian. Otherwise, you will need to send it back.
 
The issue is with U9 going bad. Although, we have received a few boards back with these issues and found they worked fine. So, make sure it is the issue. If you are sure, then request an RMA. 
 
It will take about 5 days to repair, burn in, and to retest the repair.
 
Gerald

Jason Kridner

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Sep 4, 2008, 6:14:21 AM9/4/08
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The other way to avoid an RMA is to make sure you have the right IDC10-to-DB9 adapter and a null modem cable.  As mentioned previously, the symptom Olivier is seeing is the same as when you have the wrong adapter/cable combination.

licks...@yahoo.co.uk

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Sep 3, 2008, 8:28:30 PM9/3/08
to Beagle Board
I had the issue with the receive line not working through U9 so I made
a little hardware fix for it. Basically made a small RS232 > TTL level
shifter using an NPN transistor, diode and resistor. Now works fine.

http://www.flickr.com/photos/27833844@N05/2808075163/

Has the details, schematics are everywhere for simple transistor based
level shifters so I wont repeat it here, but basically take the RX
from pin 2 of the RS232, and use a transistor to invert and hold the
OMAP RX line low, found at test point TP22. This relied on my faulty
U9 chip holding the OMAP RX line high at 1.8v using it's internal 10k
pullup and not shorting it high (I don't know what other peoples cases
would be, but it's worth checking it out properly).

I did this because my beagleboard was in UK customs for two weeks and
I didn't fancy the prospect of going a few more weeks without a
working board :o)

Dirk Behme

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Sep 4, 2008, 1:28:59 PM9/4/08
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Jason Kridner wrote:
> The other way to avoid an RMA is to make sure you have the right
> IDC10-to-DB9 adapter and a null modem cable. As mentioned previously,
> the symptom Olivier is seeing is the same as when you have the wrong
> adapter/cable combination.

Maybe

http://elinux.org/BeagleBoardFAQ#Serial_connection_.231

Steps #1 - #4 can help.

Please note the 'ATTENTION' section of step #4

http://elinux.org/BeagleBoardFAQ#Serial_connection_.234

too.

Dirk

> On Sep 3, 2008, at 7:16 PM, Gerald Coley wrote:
>
>> Well, if you can replace U9, then you can avoid an RMA. It is very
>> tough to do. Then you will need to burn it in and then it could fial
>> agian. Otherwise, you will need to send it back.
>>
>> The issue is with U9 going bad. Although, we have received a few
>> boards back with these issues and found they worked fine. So, make
>> sure it is the issue. If you are sure, then request an RMA.
>>
>> It will take about 5 days to repair, burn in, and to retest the repair.
>>
>> Gerald
>>
>> On Wed, Sep 3, 2008 at 3:03 PM, Olivier Singla
>> <olivier...@gmail.com <mailto:olivier...@gmail.com>> wrote:
>>
>>
>> Gerald,
>>
>> Just got my beagle board from Digikey.
>> I have the very same issue as described here:
>> rs232 working only in one direction (beagle->pc).
>> I had it working once (pc->beagle). Also a few times I had garbage
>> characters
>> while typing. Now I have nothing, even after many power cycles.
>> Is there a way to avoid a RMA?
>>
>> Thanks,
>> ~Olivier
>>
>> On Aug 23, 7:08 pm, "Gerald Coley" <ger...@beagleboard.org

>> <mailto:ger...@beagleboard.org>> wrote:
>> > It does sound like the serial port is bad in one direction I
>> suggest you
>> > enter an RMA and return the board for repair. We have had a few
>> boards
>> > already with this issue.
>> >
>> > Gerald
>> >
>> > On Sat, Aug 23, 2008 at 11:33 AM, Joe <joe.plu...@gmail.com
>> <mailto:joe.plu...@gmail.com>> wrote:
>> >
>> > > OK, from reading some of the posts it sounds like I may have a bad
>> > > serial on my beagleboard, but I thought I'd run it past you to
>> verify
>> > > that I am not missing something.
>> >
>> > > I am running my beagleboard from a 5v power supply. I have
>> the serial
>> > > connected to my computer and I get a good display of the booting
>> > > process. My issue is that I am unable to issue any commands
>> to the
>> > > beagleboard. Anything that I type using HyperTerm or TeraTerm
>> doesn't
>> > > show up (it sits at the OMAP3 beagleboard.org

>> <http://beagleboard.org/> # prompt).

Joe

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Sep 5, 2008, 5:26:36 AM9/5/08
to Beagle Board
Does the IDC10 - DB9 on the PC need the same pinouts?
> >>     > > Thanks.- Hide quoted text -

Robert Hibberdine

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Sep 5, 2008, 7:35:43 AM9/5/08
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Yes. Pins 1 - 5 on IDC go to pins 1 - 5 on DB9.

As I have found out the hard way there appear to be 2 types of these
IDC to DB9 connectors. One as above which is what you want and the other
where IDC:1 -> DB9:1, IDC:2 -> DB9:6, IDC:3 -> DB9:2, IDC:4 -> DB9:7
etc etc

It might be (without thinking about it too hard :-) ) with a paticular
serial cable the second (wrong) type of connector might give comms in
one direction only...

Bob.

Joe

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Sep 5, 2008, 2:06:03 PM9/5/08
to Beagle Board
So then how do I know if the serial port (hardwired) on the
motherboard
has the correct pinouts?

On Sep 5, 7:35 am, Robert Hibberdine <bob.hibberd...@ntlworld.com>
wrote:
> >> - Show quoted text -- Hide quoted text -

Gerald Coley

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Sep 5, 2008, 2:11:19 PM9/5/08
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Download the new Rev B5 System Reference Manual for the BeagleBoard. It has some pictures to help explain the configuration.
 
Gerald

Robert Hibberdine

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Sep 5, 2008, 2:22:57 PM9/5/08
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Ah. Sorry. I completely misread your first question !!!
I have just spent some hours over a period of days trying to communicate
with my Beagleboard wtih the wrong type of IDC to DB9 connector plugged
in to the Beagleboard. That is the connector I thought you were refering
to.!

The actual answer to your question is: You'll need the IDC to DB9
connector that came with your motherboard.
This answer is probably not much help to you.. Sorry for the noise.

Bob

dale...@gmail.com

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Sep 7, 2008, 11:54:47 AM9/7/08
to Beagle Board
I was/am having problems with a working serial cable with garbage
characters, but have a possible solution.
The first time I tested out the Beagleboard, it worked fine powered
over AC adapter, with serial, DVI, SD present, everything
worked fine.

Later I tried it with just A/C and serial connected. most of the
characters come out were garbage, about 20% readable.
Part of the time input was accepted. This was with both a USB serial
adapter and the built-in serial on my laptop.
After several reboots, I switched to USB powered, then about 98% of
the characters were correct.
Looking at my setup, I noticed that the serial cable I use is a 9pin
to RJ54 <-> RJ54 to 9pin.
I suspect this cable is not correctly grounding the board given that
the board only connects the 3 pins.

If the serial ground isn't connected properly, and the AC adapter
isn't keyed (grounded), it would make sense if the ground floated
a bit and causes serial noise.

Something to verify before sending the board in for RMA. *

* I found this thread and started worrying about having to RMA the
board before I figured out the problem.
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