DockStar JTAG

[bzboi]

$this->bbcode_second_pass_quote('klingon', 'O')penocd comes back with a bunch of error msgs.

[klingon]

This is when you start Openocd in the first terminal, not in the second terminal where you do the telnet and all the other commands, so will not be able to do the reset/halt trick.

$this->bbcode_second_pass_quote('klingon', '')$this->bbcode_second_pass_quote('jtagfun', '
')When n_SRST is not used, do you need to push the Reset button at all (the "work around" suggested by wiki) when starting OPENOCD?

[firestormv1]

Well, I am not sure what to do at this point. I was able to get rid of the errors and now OpenOCD reliably detects the processor however, I still can not get a read on 'nand probe 0'

Here is the output of the telnet session.
$this->bbcode_second_pass_code('', '
Open On-Chip Debugger
> init
> sheevaplug_init
target state: halted
target halted in Thumb state due to debug-request, current mode: Supervisor
cpsr: 0x400000f3 pc: 0xffff0a42
MMU: enabled, D-Cache: enabled, I-Cache: enabled
> nand probe 0
unknown NAND flash device found, manufacturer id: 0x00 device id: 0x00
probing failed for NAND flash device
')

Grasping at straws, I even followed Kragorn's idea (I think) and used a laptop to IDE adapter thinking it was my smokestack adapter and I still am unable to do "nand probe 0"

My smokestack adapter is just a 2.0mm header soldered to a standard (don't know the measurement) header and is reinforced to allow me to connect and disconnect repeatedly. I figured I'd be having to do this a bunch, so I wanted a good connector.

To add to the frustration, I was able to acquire a second one which is still un-modified. When I start up OpenOCD, I hold down the reset button while issuing the halt command, then I can follow with init, sheevaplug_init and nand probe 0 and it all just works as everyone here and the howto specifies although I am extremely leary about doing anything with the bootloader as I don't want to end up with a 2nd brick on my hands. This means that everything else (PC, TAIO JTAG, OpenOCD, dockstar.cfg, wiring) all work.

I'm really out of ideas here and beginning to think that I'm just going to have to deal with a really bricked dockstar. This thing was working correctly up until the moment where I stupidly typed nand erase into uboot and has been bricked since.

Anyone have any suggestions on what I can try next? Thank you all for helping me out on this.

ETA: If I use the load image and the resume commands from the HOWTO, does the image get loaded to RAM or to the flash? I'm guessing to the RAM and only goes to the flash if a nand write.e command is issued?

[firestormv1]

I GOT IT!!!

Ok, after bashing myself in the head with this thing long enough, I finally figured it out. On a dockstar that has NOT had it's nand erased, e.g. you didn't do something stupid like I did and type in "nand erase", you can just connect the dockstar to JTAG, fire up OpenOCD, and hit the reset switch and all is good.

IF you did nuke the NVRAM (like me), you MUST do the reset trick. Here's how it goes:

From step 3 of the HOWTO:
3: type init (DO NOT HIT ENTER!)
4: hold down the reset switch with one hand.
5: With the other hand type halt.
6: Hit enter and simultaneously release the reset switch. You should now see the following output:
$this->bbcode_second_pass_code('', '
> halt
target state: halted
target halted in ARM state due to debug-request, current mode: Supervisor
cpsr: 0x000000d3 pc: 0xffff0000
MMU: disabled, D-Cache: disabled, I-Cache: disabled
')
YOU MUST GET THE "target halted in ARM state" OR IT WON'T WORK!.

7: type in "sheevaplug_init" and hit enter. If you get a similar HALT statement like the code above, it will probably say "target halted in thumb state" you must repeat the process.
8: type in nand probe 0
You should get the much wanted message:
$this->bbcode_second_pass_code('', 'NAND flash device 'NAND 256MiB 3,3V 8-bit' found')
9: Proceed to load the image and write the RAM. (from step 13)

I apologize if this is redundant to the HOWTO article, but the timing may not be emphasized enough.

I also noticed that there was a difference between halts:

Bad halt:
$this->bbcode_second_pass_code('', '
> halt
target state: halted
target halted in Thumb state due to debug-request, current mode: Undefined instruction
cpsr: 0xa00000fb pc: 0xffff0cea
MMU: enabled, D-Cache: enabled, I-Cache: enabled
')

Good halt:
$this->bbcode_second_pass_code('', '
> halt
target state: halted
target halted in ARM state due to debug-request, current mode: Supervisor
cpsr: 0x000000d3 pc: 0xffff0000
MMU: disabled, D-Cache: disabled, I-Cache: disabled
')

If the proc is not halted properly, then sheevaplug_init and following commands won't work and you'll be scratching your head like I've been.

I want to thank everyone here for helping me out with this. Although I'm still terrified of JTAG, at least I know that if I do something stupid and brick my dockstar, I can get it back.

[jtagfun]

$this->bbcode_second_pass_quote('firestormv1', 'I') GOT IT!!!
IF you did nuke the NVRAM (like me), you MUST do the reset trick. Here's how it goes:

$this->bbcode_second_pass_quote('Admin', 'N')ice!!! Glad to hear all of this - can someone put it all into a big wiki page?

[firestormv1]

Ok, finally got the writeup fully completed and published.

@bzboi: Since in my case I had done something stupid and nuked the flash, the reset workaround was required. Just for grins, I tested an unbricked Dockstar and it worked without the reset workaround.

You can see the writeup (complete with a ton of screenshots and pictures) here: http://wp.me/pNDfp-9B

Please let me know what you think. You are welcome to incorporate this into the Wiki as needed. (I don't even know if I have access to make changes?)

Thank you all for your help!

FIRESTORM_v1

$this->bbcode_second_pass_quote('firestormv1', 'O')k, finally got the writeup fully completed and published.

@bzboi: Since in my case I had done something stupid and nuked the flash, the reset workaround was required. Just for grins, I tested an unbricked Dockstar and it worked without the reset workaround.

You can see the writeup (complete with a ton of screenshots and pictures) here: http://wp.me/pNDfp-9B

Please let me know what you think. You are welcome to incorporate this into the Wiki as needed. (I don't even know if I have access to make changes?)

Thank you all for your help!

FIRESTORM_v1

[firestormv1]

@bzboi - Good catch, I've updated the post to include that information.

The only reason why I erased the whole chip was because mine was already blank to begin with after an errant "nand erase" in uboot so in my case, the env vars are already blown away. Thankfully I have other DS's I can compare the printenv's from and recreate them in the resurrected dockstar.