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I'v killed my 520GC
Posted: Mon Jan 18, 2010 10:57 am
by 538
Now Asus just light LANs and WAN on (all time when power is on).
Power and Air lights off.
No pings. Nothing.
I think it was happened after erase cfe and erase nvram.
Hyperterminal shows nothing (I use TTL-232R-3v3)
Is it possible to reanimate it?
Re: I'v killed my 520GC
Posted: Mon Jan 18, 2010 10:39 pm
by mightyohm
Unless you manage to find the JTAG port it is probably dead.
How did you blow away CFE and nvram?
Re: I'v killed my 520GC
Posted: Tue Jan 19, 2010 12:12 am
by 538
Oh, I think I was crazy
It was some kind of research...
According to the preview datasheet of BCM5354 it has JTAG and UART.
But how to find JTAG?
Re: I'v killed my 520GC
Posted: Tue Jan 19, 2010 12:19 am
by mightyohm
I haven't looked for it. It's possible that the pins are brought out to headers or pads somewhere on the board, but unfortunately I have no idea where. Have you checked to see if anyone has posted about JTAG on the WL-520gu over on the openwrt forums?
Re: I'v killed my 520GC
Posted: Tue Jan 19, 2010 2:42 am
by 538
Yes, of course, I'v checked it but unfortunately. It seems nobody has even schema of this router.
I'v tried to find datasheet of processor - same result.
Re: I'v killed my 520GC
Posted: Tue Jan 19, 2010 8:40 pm
by mightyohm
I guess it's time for a new router then. Good thing they are cheap these days, I saw them for $30 on Newegg recently.
Re: I'v killed my 520GC
Posted: Wed Jan 20, 2010 3:26 am
by 538
Yes, you are right.
But I have an interest to repair it.
Price doesn't matter.
Re: I'v killed my 520GC
Posted: Wed Jan 20, 2010 8:24 am
by mightyohm
The brute force way to find the JTAG connections (if they exist) might be to sacrifice a bricked WL-520gU. Desolder the CPU and then probe the JTAG pads to see if they come out anywhere else on the PCB.
Re: I'v killed my 520GC
Posted: Thu Jan 21, 2010 6:44 am
by 538
Hmmm... As I understand 520GC and 520GU have the same PCB. If so it's useless because they have just UART pads.
It should be some other router based on BCM5354 which has JTAG pads.
Am I right?
Re: I'v killed my 520GC
Posted: Thu Jan 21, 2010 9:56 am
by mightyohm
I guess my theory is that the JTAG pads are somewhere on the board, maybe not as obvious as the UART pads. I was hoping that somewhere in the layout, the are traces or vias you could tap into. There are some very small solder points around the board, it's possible that some of those are for the JTAG interface.