Joined: 26 Jan 2008 Posts: 13049 Location: Behind The Reset Button
Posted: Sat Jul 28, 2012 20:01 Post subject: RT-N66U Jtag
In preparation for flashing the rt-ac66u cfe to the rt-n66, I thought I would play with jtag on the rt-n66u..
J2 sure looks like a jtag header. Using an ohm meter, it tests out.
I thought it would be a standard pin out.
1 = nTrst
3 = tdi
5 = tdo
7 = tms
9 = tck
2 ~ 10 = ground
Using the latest release of tjtag (donation version), a probeonly yields all fffff's.. (cable not connected, etc.)
I spent some time hunting & switching pins.. Never got it to see the processor.. even though tjtag may not "recognize" the processor, it will see it.
What I will call the "standard" pinout as posted above.. this config did show that it may be working.
This was the only config that would change the status of the led's doing a probeonly. The power light would go out, and the internet light, the 2.4, and the 5ghz lights would glow dim..
Any other wire configs, had no effect. So I believe the standard pinout is correct.
I (we) need a little help from the rest of the "gearheads" on the forum to get this sorted out.
Anyone else played with jtag on this router? _________________ [Moderator Deleted]
Did you solder your header on top or bottom of the PCB? I noticed that if it is on top it will interfere with the cover on the router. Thinking of putting mine on the bottom, at least if i have to cut a hole it will be through the bottom of the case. _________________ Peacock Thread-FAQ -- dd-wrt Wiki
Joined: 26 Jan 2008 Posts: 13049 Location: Behind The Reset Button
Posted: Tue Jul 31, 2012 23:43 Post subject:
Dark_Shadow wrote:
Did you solder your header on top or bottom of the PCB? I noticed that if it is on top it will interfere with the cover on the router. Thinking of putting mine on the bottom, at least if i have to cut a hole it will be through the bottom of the case.
The top.. I pushed the pins through the pcb just a bit before soldering so they do not interfere.. There is a plate on the bottom of the pcb that had to be removed to solder, then put back. _________________ [Moderator Deleted]
pin 2 ~ 10 are indeed ground but that doesn't mean that tck, tms, ~, etc. are not correct in your link.
I may not have tried your link on purpose.. but when I was messing with it.. I made a "map" of pins & wires and tested what I believe was every possible combination (kind of like a game of sudoku ). It didn't take too long for confusion to set in and I may have missed one or two combinations.
As stated earlier.. My 1st config was the only config that would change the status of the leds upon a probeonly but as also said, I may have missed / messed up a connection combination.
I'll keep at it as time permits.
Even though tjtag may not recognize the processor, it should still see it if connected properly. Instead of all ff's for the processor id, it should have some other type of hex id code which it never did.
Maybe possible that J2 may not be jtag at all?? dunno.
Maybe a couple of the guys that have a fast track to asus (Rmerlin, andyMS) could ask asus for the jtag pin out.
Once I am certain of the pinout, I can try to get a hold of T~ and ask for assistance with the software. _________________ [Moderator Deleted]
The IR length of 1 is wrong, it should be either 5 or 32 depending on which mode the jtag TAP controller is in.
Can you override that on the cmd line? _________________ Kernel panic: Aiee, killing interrupt handler!