JTAG in Zyxel 660HW

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AlWise
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JTAG in Zyxel 660HW

Post by AlWise » Tue Jan 30, 2007 2:13 pm

Hello,
My router Zyxel 660HW has a bad bootloader so neither the web nor the FTP nor the serial port respond. The only way to upload the bootloader would be throug the AR7 JTAG but I culn't find any JTAG conection in the board. Any ideas? Anybody had this problem before?
Thanks,
Al
Last edited by AlWise on Tue Jan 30, 2007 4:33 pm, edited 3 times in total.
mstombs
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Post by mstombs » Tue Jan 30, 2007 2:23 pm

I think you mean JTAG, see discussion in other threads for more info and further links

viewtopic.php?t=858
viewtopic.php?t=827
Last edited by mstombs on Tue Jan 30, 2007 3:54 pm, edited 1 time in total.
AlWise
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Post by AlWise » Tue Jan 30, 2007 3:11 pm

Thanks, I had a bad night.
Leo
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Post by Leo » Sun Feb 25, 2007 7:37 pm

On my Zyxel there is space to solder a 14-pin header on the underside of the board, labeled JP3. (See attatched photo, slap bang in the middle!)
Could this be the JTAG header?

Leo
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Photo of the bottom (solder) side of a Zyxel 660 router.
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mstombs
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Post by mstombs » Sun Feb 25, 2007 8:06 pm

Leo wrote:On my Zyxel there is space to solder a 14-pin header on the underside of the board, labeled JP3. (See attatched photo, slap bang in the middle!)
Could this be the JTAG header?

Leo
Sure looks like it, should be able to check with a sharp pointed multimeter that pins 2,4,6,8,10,12 are all connected to 0V, pin 14 to +3.3V.

Are these surface mount pads only? On the ADSL2MUE the header has 'through hole' connections and everything easily accessible on edge of board.

Soldering in the middle of the board like that would really be a last resort!

NB if you are only doing as a one off I'd recommend soldering very thin bits of insulated wire straight onto the pads and not bother with permanent header - just cut them off when problem solved.
Leo
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Post by Leo » Sun Feb 25, 2007 10:47 pm

Thanks.

2,4,6,8 and 10 are all grounded, but 12 seems to be something else. 14 is 3.3V though, so I guess it's close enough.... (I wonder what 12 is for?)

They are surface mount pads, but it's only a one-off, and anyway it wouldn't fit back in the box with a header attatched!

Leo
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