JTAG pinouts and guides ! ! !

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Murrkf
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PostPosted: Wed Oct 22, 2008 0:46    Post subject: Reply with quote
If you have pinout picts or information, be sure to add them to the wiki, here.

http://www.dd-wrt.com/wiki/index.php/JTAG_pinouts

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diagpope
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Joined: 22 Oct 2008
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PostPosted: Wed Oct 22, 2008 2:41    Post subject: JTAG pin locations for Netgear WNR834B V1 ? Reply with quote
I am new to this forum and have studied a lot about using JTAG but have never done a de-brick procedure before. I would like to do this on a bricked Netgear WNR834B V1 but have not found the JTAG header. Can somebody please point me to where these pins are? I can supply pictures of the board if that helps.

Many thanks.or
Murrkf
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Joined: 22 Sep 2008
Posts: 11223

PostPosted: Wed Oct 22, 2008 3:39    Post subject: Reply with quote
Post pictures of the board.

Be sure your router needs this prior to doing a jtag. If you are not sure, post a post in the forums explaining what you did and what you are seeing on the lights and if you try to ping the router.

_________________
SIG:
I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor. So See this:
http://i31.tinypic.com/24mz3ms.png

LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."
diagpope
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Joined: 22 Oct 2008
Posts: 15

PostPosted: Wed Oct 22, 2008 20:17    Post subject: JTAG pin locations for Netgear WNR834B V1 ? Reply with quote
Murrkf,

many thanks for getting back so quickly. I took a few pics of the inside of the refurbished Netgear WNR834 B V1 but must admit that either the Camera or my skills taking pics suck. The best over all pic of the circuit board's top is attached. I can provide more detailed pics if that helps.

Here is what I did to the unit:
1) Flashed from the original Netgear firmware to Sveasoft Talisman (result: worked)
2) Flashed the mini wrt v0.24 for the WNR834B V1 (result: worked)
3) Tried to enable cifs mount (result: failed and got stuck, reboot, reset did not help)
4) Any attempt to reflash failed after that

Since then the unit behaves as follows:
When applying power the power led stays solid amber. The switch is still functional but no WLAN Led comes up.
When applying power while pushing the reset and then releasing reset the amber led keeps blinking in approx. 1 sec intervals. arp -a commands find the router as MAC 00:00:.. etc. and at no time there is any ping response at all. As said I have never jtag'ed myself but hope that you can give me a hand on reviving the router.
Thanks a lot in advance.



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redhawk0
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Joined: 04 Jan 2007
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Location: Wherever the wind blows- North America

PostPosted: Sat Oct 25, 2008 23:00    Post subject: Reply with quote
Serial and JTAG on a WRT54G2 V1 unit. (new JTAG style connectors)

The pins can be cleaned of the green epoxy coating...with the 12 pin connector sandwiched on either side of the motherboard...and soldered on. The connector will still fit inside the radio's enclosure.

Also attached (in this picture) is the Serial Connector. 5 pin connector bent at a 30 degree angle so it will still fit inside the case...yet provide access to the +3.3V(pin1), Tx(Pin2), Rx(Pin3) and GND(Pin5) pins....pin4 is not connected to anything.

The JTAG connector is of normal pinout as any other Linksys unit...So is the Serial.

(we are working on JTAG recognition next...This device is currently not supported) - (Now Supported 11/2008)

Hopefully, this will help someone else to connect with the same type of JTAG connection.

redhawk



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_________________
I currently test dd-wrt on Asus, Buffalo, Linksys, and Netgear. Too many to list.

Looking for more test units (newer models) for the project...got a brick?...PM me to make a donation. (USA) A donation is not a debricking service....it is a way to "Give back" to the dd-wrt project.

I do NOT provide personal assistance through chat or phone....so please don't ask.


Last edited by redhawk0 on Sun Jan 25, 2009 19:13; edited 2 times in total
Murrkf
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Joined: 22 Sep 2008
Posts: 11223

PostPosted: Sun Oct 26, 2008 5:06    Post subject: Re: JTAG pin locations for Netgear WNR834B V1 ? Reply with quote
diagpope wrote:
As said I have never jtag'ed myself but hope that you can give me a hand on reviving the router.
Thanks a lot in advance.


Wish I could help, but I don't see a place for a jtag on that unit. However, the back of the router is cut off. Try to post another picture that shows the whole board.

Redhawk or someone else might be able to assist. They are experts at this.

Better to post this in the main forum though, as this is supposed to be just for jtag pinouts.

_________________
SIG:
I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor. So See this:
http://i31.tinypic.com/24mz3ms.png

LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."
Shawn360
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Joined: 26 Jul 2008
Posts: 1237

PostPosted: Sun Oct 26, 2008 5:26    Post subject: Re: JTAG pin locations for Netgear WNR834B V1 ? Reply with quote
diagpope wrote:
I am new to this forum and have studied a lot about using JTAG but have never done a de-brick procedure before. I would like to do this on a bricked Netgear WNR834B V1 but have not found the JTAG header. Can somebody please point me to where these pins are? I can supply pictures of the board if that helps.

Many thanks.or

Looks like it does not have one.
According to this it has a jtag port.
But the picture you took does not show one.
http://www.dd-wrt.com/wiki/index.php/Supported_Devices#Netgear


Last edited by Shawn360 on Sun Nov 16, 2008 17:01; edited 1 time in total
Doramius
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Joined: 29 Aug 2008
Posts: 311

PostPosted: Tue Oct 28, 2008 21:11    Post subject: Reply with quote
redhawk0 wrote:
Serial and JTAG on a WRT54G2 V1 unit. (new JTAG style connectors)

The pins can be cleaned of the green epoxy coating...with the 12 pin connector sandwiched on either side of the motherboard...and soldered on. The connector will still fit inside the radio's enclosure.

Also attached (in this picture) is the Serial Connector. 5 pin connector bent at a 30 degree angle so it will still fit inside the case...yet provide access to the +3.3V(pin1), Tx(Pin2), Rx(Pin3) and GND(Pin5) pins....pin4 is not connected to anything.

The JTAG connector is of normal pinout as any other Linksys unit...So is the Serial.

(we are working on JTAG recognition next...This device is currently not supported)

Hopefully, this will help someone else to connect with the same type of JTAG connection.

redhawk
Yeah, I'm trying to work on that. I soldered wires to the pads, and have a connector for it. Still haven't decided how I want to mount it on the chassis, but I'm trying to squeeze time in to work on it.
diagpope
DD-WRT Novice


Joined: 22 Oct 2008
Posts: 15

PostPosted: Sun Nov 09, 2008 13:49    Post subject: Jtag connector of Netgear WNR834B V1 Reply with quote
Posting two more pictures of the top of a Netgear WNR834B V1 board. Sorry that these are not crisp pics. I am hoping somebody can point me to the JTAG connector. Many thanks.


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Doramius
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Joined: 29 Aug 2008
Posts: 311

PostPosted: Sun Nov 09, 2008 17:48    Post subject: Reply with quote
I don't see a JTAG, but It looks like you have a Serial>TTL point in the bottom right corner of the second pic.
diagpope
DD-WRT Novice


Joined: 22 Oct 2008
Posts: 15

PostPosted: Mon Nov 10, 2008 15:11    Post subject: Serial connector on Netgear WNR834B V1 Reply with quote
Doramius,

is the serial connector the JP1 right above the reset button next to the 4 ethernet ports ?
Any ideas on the pinout, are they standard (left to right) ? If so I just need to find a web site showing where to find software and a manual how to debrick this unit.

Thanks again.
Doramius
DD-WRT User


Joined: 29 Aug 2008
Posts: 311

PostPosted: Mon Nov 10, 2008 16:55    Post subject: Reply with quote
It "looks" like a serial/TTL connection. Can you get a better picture straight on from the top and bottom of that corner?


There are generally 2 types of pinouts. VCC/GND/TX/RX -OR- VCC/TX/RX/GND, but they can do it however they feel. Also, to go from serial to TTL, you'll need an adapter. A serial connection is NOT a JTAG. You'd need an adapter with a MAX232 chip. You can probably find a kit online for <$15. You just need to solder the parts in.
redhawk0
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Joined: 04 Jan 2007
Posts: 10915
Location: Wherever the wind blows- North America

PostPosted: Sat Nov 29, 2008 14:58    Post subject: JTAG for Netgear WGR614Lv8 Reply with quote
Here is the JTAG for the NetGear WGR614Lv8 unit.

A 100ohm resistor needs to be connected from pin marked 1 to a +3.3V supply (I use the +3.3V from the Serial connector right next door.

redhawk



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_________________
I currently test dd-wrt on Asus, Buffalo, Linksys, and Netgear. Too many to list.

Looking for more test units (newer models) for the project...got a brick?...PM me to make a donation. (USA) A donation is not a debricking service....it is a way to "Give back" to the dd-wrt project.

I do NOT provide personal assistance through chat or phone....so please don't ask.


Last edited by redhawk0 on Tue May 12, 2009 20:19; edited 1 time in total
KeithB
DD-WRT User


Joined: 22 Jun 2008
Posts: 461

PostPosted: Mon Dec 01, 2008 2:02    Post subject: Re: Serial connector on Netgear WNR834B V1 Reply with quote
diagpope wrote:
is the serial connector the JP1 right above the reset button next to the 4 ethernet ports ?
Yup, that's it up there near one corner of the board Smile
diagpope wrote:
Any ideas on the pinout, are they standard (left to right) ? If so I just need to find a web site showing where to find software and a manual how to debrick this unit.

I don't remember at the moment, but I can pull my v1 out and trace it for you in a few minutes. :D

EDIT: Here you go... From the top to the bottom, the console port pins are:

1 GND
2 TXD
3 RXD
4 Vcc (3.3V DC)

Unfortunately, there are no obvious JTAG points on the v1 motherboard. Sad I suspect they are scattered over the many small test points cryptically labeled TPnn all over the board, but I've never seen any description of them. Good luck!

_________________
3x Netgear WNDR3300 - Eko V24 sp2 SVN 11793 std-nokaid-nohotspot-nostor
1x Asus RT-N16 - re-capped after two years
diagpope
DD-WRT Novice


Joined: 22 Oct 2008
Posts: 15

PostPosted: Mon Dec 01, 2008 2:46    Post subject: Awaiting my rescue cable for serial connector Reply with quote
Hey KeithB,

many thanks for your heads up with the Netgear Router WNR834B V1. I (still) have the bricked V1, another bricked V2 I had returned to the store because I got tired of it. After I debricked a Linksys WRT350N V1 successfully now I am eager to try the procedure via the serial port and a console on the Netgear. I have measured via Ohm-meter the GND connector of the Netgear and found 3.3V on all other three pins (maybe pull-up resistors on the TX and RX ?). Thanks for giving me the pinout for the four pins !
At the moment I am waiting for a USB to Serial/TTL adapter purchased at eBay to try the magic.

I would appreciate if you could give me a hint where to find the correct images and commands to erase and re-flash the WNR834B.
Cheers.
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