Discussion:
GuruPlug JTAG/console adapter
Donald Gordon
2011-07-25 22:40:26 UTC
Permalink
Hi

Does anyone have one of these I could borrow (I'm in Wellington).
I've bought a GuruPlug off trademe but it doesn't come with the dev
kit which is going to make installing debian on it a little tricky...

thanks

donald

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Nick Rout
2011-07-25 22:49:35 UTC
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Post by Donald Gordon
Hi
Does anyone have one of these I could borrow (I'm in Wellington).
I've bought a GuruPlug off trademe but it doesn't come with the dev
kit which is going to make installing debian on it a little tricky...
I ended up jerry building a serial adaptor. You don't need the full
jtag kit to get a root console on bootup. I will find the howtos and
post them when I find them.

Trickiest part was finding the serial port connector IIRC

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Donald Gordon
2011-07-25 22:56:02 UTC
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That sounds useful. I can build my own serial adapter but yeah,
finding the plug will be the hard bit. I've got an old-style
SheevaPlug and I've had to use JTAG once, when I wrote a kernel over
the top of u-boot... guess I'll just have to be ultra-careful with the
GuruPlug.

donald
Post by Nick Rout
Post by Donald Gordon
Hi
Does anyone have one of these I could borrow (I'm in Wellington).
I've bought a GuruPlug off trademe but it doesn't come with the dev
kit which is going to make installing debian on it a little tricky...
I ended up jerry building a serial adaptor. You don't need the full
jtag kit to get a root console on bootup. I will find the howtos and
post them when I find them.
Trickiest part was finding the serial port connector IIRC
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Nick Rout
2011-07-25 22:58:29 UTC
Permalink
Post by Nick Rout
Post by Donald Gordon
Hi
Does anyone have one of these I could borrow (I'm in Wellington).
I've bought a GuruPlug off trademe but it doesn't come with the dev
kit which is going to make installing debian on it a little tricky...
I ended up jerry building a serial adaptor. You don't need the full
jtag kit to get a root console on bootup. I will find the howtos and
post them when I find them.
Trickiest part was finding the serial port connector IIRC
Here is what I posted on CLUG after I got it working:

Reporting back with success!

to recap, I have a globalscale guruserver plus for which I could not
remember the root password, making it rather difficult to make some
software mods and updates.

The usual way into this machine in such circumstances is via a
proprietary 'jtag' box
http://www.globalscaletechnologies.com/p-28-guruplug-jtag.aspx which
provides a usb serial interface. The jtag box plugs into the server
via two plugs, one 4 pin and the other 8. The jtag box was a little
expensive, $US39, which I would have worn, but the same again for
shipping? No thanks).

However my investigations on the net, coupled with help from this
list, revealed that the 4 pin port on the server is in fact just a
3.3v serial port, 4 pins for GND, Tx, Rx and 3.3v. see
http://www.plugcomputer.org/plugwiki/index.php/GuruPlug#Serial

Also I found a page on how to turn an el cheapo nokia usb phone cable
into a serial cable
http://buffalo.nas-central.org/index.php/Use_a_Nokia_Serial_Cable_on_an_ARM9_Linkstation
(well it is a usb to serial cable, but that page goes through a lot of
useful stuff on pinouts etc).

Also someone on the chch robotics list put me onto a NZ site that
shipped the tiny little connectors to attach to the server. (These
people are crazy, they ship overnight freight free, my order was only
$1.64, they must have spent $10 to courier it!).

So with a little help from my friends and a bit of duct tape and
swearing, I got a serial console and managed to set the init script to
/bin/bash. Thereafter I ran passwd and set the root password, rebooted
and Bob's your uncle.

I have to say my cabling is a bit hit and miss, fiddly little wires
and all, I'll find my soldering iron and some shrink wrap one day and
do a better job.

Thanks for all the pointers everyone :) </quote>

The picoblade connectors are here:

http://newzealand.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2799162

I got

279-9162 5 $0.32 $1.60 Connector,PCB,housing,1.25mm pitch,4 way
279-9516 10 $1.60 $16.00 Connector,PCB,crimp,socket to socket lead,150mm

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