[Openec] Few questions about KB3700/3926

[Frieder Ferlemann]

Hi,

Richard A. Smith schrieb:
> Frieder Ferlemann wrote:
> 
>>> Some day I might help with that, you say I can disassemble the firmware,
>>> and give you directions how to power up the CPU?
>> Most likely - that would be great!
> 
> Most of the info needed to determine the proper sequencing is in the AMD 
> data sheet which is available.  The parts you are missing are what IO 
> lines are connected to the enables for each of the regulators.  Very 
> little of that has changed across the XO versions.

Ok, this gives others with an up to date XO (and with a debug adapter)
a chance to build on the (for 8 months untouched) power handling code.

To give a reference, the code that stops the XO from being powered by
OpenEC is here:
http://dev.laptop.org/git?p=projects/openec;a=blob;f=power.c;hb=HEAD

(could likely also be done with OpenEC's built-in monitor)



>>> Btw, using some instruments and destroying a single OLPC you could 
>>> figure the schematics by unsoldering the parts?
> 
> I don't think you would need to destroy an XO for the purposes of 
> figuring out how the EC is wired.  It would just take a lot of care.
> 
>> While this might technically work (given sufficient resources/time)
>> it socially probably would not: you would get to know how it is
>> done (but not why, or how future version would look like, and
>> the chance to be involved early in the development phase would be lost).
> 
> Perhaps not quite so bad.  You have access to devleopers that can help 
> guide you just not tell you flat out.

might be a case of inadequate self censorship, sorry.


>>> I guess that small devices like sensors and voltage regulators should 
>>> have datasheets.
> 
> Most of those would not be needed since they are simple parts with just 
> off/on enable lines.  The main power plant IC however does have some 
> lines that the EC twiddles for various battery charging states.  I'm not 
> sure if the datasheet for that IC is public.  I'll have to check.
> 
>> Richard, Paul, are you following this thread?
> 
> I am,  with much interest. But I've just had too much other stuff to do 
> ...

Fine (the first sentence).

Greetings,
Frieder