Am 25.07.2010 um 12:45 schrieb Dr. H. Nikolaus Schaller:
> Hi Peter,
>
> Am 24.07.2010 um 20:34 schrieb Peter Van Akelyen:
>
>> If you removed all 11 screws at the bottom,
>
> yes
>
>> you should be able to remove keyboard when you click back the plastic things
>> that hold the keyboard in place.
>
> Ah, ok. I found four snap-holders at the top row.
>
> But it appears as if the keyboard is screwed in the middle...
>
> Found it: there is a 12th screw sealed by a label :)
>
>> Then you can remove keyboard and disconnect cable to touchpad.
>
> Ok!
>
>> Also make sure you have removed the plastic lcd covers on both sides.
>
> It means tilting the display in 90 degree open mode and pressing from the
> keyboard side softly against the U-shaped covers, right where they join the
> keyboard bay. They are mounted with two snap-fits.
>
>> It may take some force to open the case, even after all screws are removed.
>
> Then, I was able to remove the front part by horizontally extracting it -
> makes quite crunchy noise :) The reason is that the cover itself has one
> snap-fit for each U-shaped cover...
>
> Finally, I have removed them by closing the LCD lid and taking a knife by
> softly pressing it into the small space between the bottom part and the
> U-shaped things. Then, they can be removed and reveal the lid mechanics and
> the screws of the PCB...
>
> After removing these screws and the LCD, I could easily get the PCB out of
> the case.
>
> Fortunately, the power socket and the SD-card reader are soldered to the
> board, so it should be possible to operate the board without peripherals
> (just RS232 and JTAG connection). BTW: if someone is looking for the RS232
> connector: they appear to be "Molex Picoblade 1.25mm", P/N 53261-0471.
>
> Phew...
>
> Next step will be to find out how to connect JTAG (to an Openmoko Debug
> Board) and how it works :)
Since some of you may be interested in my findings, here some first ones:
1) the Openmoko debug board uses a FTDI JTAG controller connected through USB -
so it can be used easily from any USB capable host
2) it appears to use the same 3.3V levels as the Mipsbook - no level shifters
required
3) it has a special 45 pin FPCB (double row) for connecting the Openmoko which
does *not* fit to the 24 pin "TEST PORT" of the Mipsbook (0.5 mm pitch, single
row)
4) but it has also a 20 pin ARM JTAG header which appears to be some standard -
but only in the ARM world - so we need some adapter to the Mipsbook main board
5) OpenOCD appears to support MIPS as well:
http://www.hermann-uwe.de/blog/openocd-a-free-software-jtag-utility-with-arm-and-mips-support
Here some more links:
Openmoko Debug Board FTDI chip:
http://wiki.openmoko.org/wiki/Debug_Board_v3#JTAG_using_FT2232
Original reference design used for the OM Debug Board:
http://www.joernonline.de/contrexx2/cms/index.php?page=126
Schematic:
http://people.openmoko.org/joerg/schematics/debug_board/OpenMoKo_Debug_Board_V3_MP.pdf
(E)JTAG for MIPS: http://www.linux-mips.org/wiki/JTAG (this page says
that OpenOCD just supports ARM processors?)
A low-cost EJTAG interface and daemon software:
http://www.totalembedded.com/open_source/jtag/mips32_ejtag.php
The description in the last link explains why JTAG debugging is a little
complicated - it appears that the debugger must push machine instructions
through the basic JTAG interface to write registers, memory etc. I.e. this
requires that the host knows the machine code of the target. Therefore it is
differnt between MIPS and ARM and even within CPU models. The basic JTAG is all
the same.
So we essentially have two approaches:
a) use the OM debug board, build an adapter cable, and adapt OpenOCD to MIPS
(E)JTAG and JZ4730 (where needed)
b) build a simple JTAG interface on some parallel port (e.g. using GPIOs of a
BeagleBoard) and use the mips32_ejtag package
For option a) it appears to be possible not only to connect the JTAG of the
Mipsbook but also the serial console since the FT2232 chip on the OM debug
board also provides a RS232-USB converter.
Anyone interested in working together for such a project?
Best regards,
Nikolaus
_______________________________________________
Mipsbook-devel mailing list
Mipsbook-devel@linuxtogo.org
http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/mipsbook-devel
