Can't connect via JTAG

[DK]

I hope you can help,  I bought the SheevaPlug from you in January 2010.

After a very unwise moment, I decided to upgrade my Ubuntu 9.04 distribution, without checking first.  As you would expect, this wasn't very successful and have managed to lock myself out of SSH.

My problem is that I cannot seem to connect via JTAG (booting to NAND and SD), I have tried 4 computers, including the one I orginaly set up the unit with , with both windows (XP, Vista & 7) and Ubuntu, but nothing seems to be able to connect.  I have used the orginal mini-usb cable and another one.  The interesting thing is that the plug is booting as the installed services still work.


I've followed the instructions on your forum many times, and orginally connected fine within minutes of opening the box.


One strange thing I've noticed is in Windows XP Device manager, USB Serial Converter A and B either one or both will report 'This device cannot start. (Code 10)', simetimes it will not recognise the plug at all and show as a USB Composite device, or Unknown device.
 

have you any suggestions?  I'm starting to feel I'm missing something obvious

In Ubuntu I did

sudo modprobe ftdi_sio vendor=0x9e88 product=0x9e8f

then the dmesg shows

[ 9679.380019] usb 4-2: new full speed USB device using uhci_hcd and address 96
[ 9679.590210] usb 4-2: configuration #1 chosen from 1 choice
[ 9679.603194] usb 4-2: Ignoring serial port reserved for JTAG
[ 9679.608560] ftdi_sio 4-2:1.1: FTDI USB Serial Device converter detected
[ 9679.608597] usb 4-2: Detected FT2232C
[ 9679.608600] usb 4-2: Number of endpoints 2
[ 9679.608603] usb 4-2: Endpoint 1 MaxPacketSize 64
[ 9679.608606] usb 4-2: Endpoint 2 MaxPacketSize 64
[ 9679.608608] usb 4-2: Setting MaxPacketSize 64
[ 9679.609271] usb 4-2: FTDI USB Serial Device converter now attached to ttyUSB0
[ 9680.600053] hub 4-0:1.0: port 2 disabled by hub (EMI?), re-enabling...
[ 9680.600062] usb 4-2: USB disconnect, address 96
[ 9680.600295] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
[ 9680.600314] ftdi_sio 4-2:1.1: device disconnected
[ 9680.840119] usb 4-2: new full speed USB device using uhci_hcd and address 97

[NewIT_Marcus]

First of all, please clarify what you mean by "upgrade ... distribution"?

Secondly, what works and what doesn't? You say that you have "lock[ed] myself out of SSH", then you say "the installed services still work".

Thirdly, are you saying that you can't establish a console connection? Were you previously able to establish a console connection, but now you can't?

The console is not quite the same as JTAG; under Ubuntu (I think this behaviour changed with Karmic), this is just fine:

Ignoring serial port reserved for JTAG

So - what is the problem that you are trying to fix?

[DK]

sorry, please excuse the random mutterings, I was trying to put all information down and lost the plot a bit.

I mistakenly thought that the SheevaPlug will run the latest ubuntu 10.04, so I did a sudo apt-get dist-upgrade.  This downloaded, and started to install, but promptly run into errors.

This created errors with SSH, stopping me logging on, so I wanted to connect via JTAG to change ssh config.

Frustratingly, I had 3 mini-USB leads that didn't seem to work.  I went out and bought another and connection is fine.

Apologies, can I delete this thread?
 

[NewIT_Marcus]

sorry, please excuse the random mutterings, I was trying to put all information down and lost the plot a bit.

I mistakenly thought that the SheevaPlug will run the latest ubuntu 10.04, so I did a sudo apt-get dist-upgrade.  This downloaded, and started to install, but promptly run into errors.

This created errors with SSH, stopping me logging on, so I wanted to connect via JTAG to change ssh config.

Frustratingly, I had 3 mini-USB leads that didn't seem to work.  I went out and bought another and connection is fine.

Apologies, can I delete this thread?
 

The reason why apt-get dist-upgrade is a bad thing is that 9.04 was the last version of Ubuntu that supported the ARM processor in the Sheevaplug.

The serial connection is NOT the same as JTAG (although it uses the same cable). You still didn't explain what you mean by "stopping me logging on"; if it was a password problem (for instance) establishing a serial connection won't help. If you broke the SSH server (but not other services), then presumably you have been able to use the serial connection to at least partly fix your system. Frankly, the results of the (failed) apt-get dist-upgrade are unpredicatable and if I were in your shoes I'd be inclined to rewrite my file system (ironically, using the installer ie JTAG).

We have read about some problems with USB cables on the plugcomputer forum, but we have only had one (other) customer report the problem to us at this time. If the cable we supplied was one of the 3 that didn't work, please e-mail Jason with your original order details and he can supply a tested replacement.

You can delete any post with the "remove" link; I would prefer that this useful information about what not to do remain here, but if you prefer to delete your posts and would like me to delete my replies, please say so.

[DK]

Hi Marcus,

Okay, I understand I thought the serial connection and the JTAG was one of the same thing.  I'm still at bottom of the learning curve for things relating to the boot, serial and JTAG part of the plug.

I'm still having a few problems maintaining a serial connection (I'm jumping from home to work computer, home works fine - but stops the mouse working, work keeps disconnecting) this must be something to do with how I'm setting up, but can't seem to find out what.

I discovered that as you suspected, the problem isn't SSH, I simply can't gain access.  With the serial it logs in and then immediately logs out, so rewiting the file system looks the only option.  I'm aiming to upgrade uboot, and move to Debian for future proofing (and a bit of fun learning).

Many thanks for your quick and informative responses

[NewIT_Marcus]

Under linux, the serial console and JTAG appear as (for example) /dev/ttyUSB0 and /dev/ttyUSB1. Logically those devices are different. Physically, they use the same USB cable.

I haven't used Windows to connect to a Sheevaplug, but my understanding is that Windows behaves significantly differently, and that (in particular) only one of these 2 devices can be used at any time.

If you're still learning, the installer can be intimidating. Id' recommend running it under linux as opposed to Windows, but the current version of Ubuntu will require a slight change to the runme.php script. However, once you get the installer working OK, you'll discover that you can easily put debian or another O/S onto the plug if desired.

http://plugcomputer.org/plugforum/index.php?topic=717.0