[Arm-netbook] 2.7.4 preproduction sample, 1.7 MD, Questions

Luke Kenneth Casson Leighton lkcl at lkcl.net
Thu Jul 9 11:43:58 BST 2020

On Thu, Jul 9, 2020 at 11:28 AM Pablo Rath <pablo at parobalth.org> wrote:

> Images can be found here (I could not upload them to the rhombus-tech
> wiki becaus a virus checker is not defined):

ah sorry :)

> https://www.parobalth.org/eoma68-a20/eoma68-A20_2-7-4_1.JPG

ok can you re-take this one *exactly* from above?  as it is slightly
to the side it is not visually possible to confirm that the gap on the
left is exactly the same as the gap on the right, because perspective
(and shadows).

> https://www.parobalth.org/eoma68-a20/eoma68-A20_2-7-4_2.JPG

it's slightly out of focus, the camera selected the ASICs not the
connector, didn't it?

> https://www.parobalth.org/eoma68-a20/eoma68-A20_2-7-4_3.JPG

ah that's better.

> https://www.parobalth.org/eoma68-a20/eoma68-A20_2-7-4_4.JPG

ah ha!  cancel that on the 1st one, that looks even on both sides, doesn't it?

ok there's one more: a picture from the *underside* - actually
*between* the PCBs (try to get some light in there).  don't for
goodness sake pry the cards apart, obviously you'll need to take the
anti-static bag out.

whilst the no 4. photo showed that the pins from the *top* row are not
showing, i.e. the Card was not inserted too low, this does *NOT*
guarantee that the card was inserted TOO HIGH.

and you will find that out by VERY CAREFULLY inspecting *between* the
PCBs.  if the Card was inserted 1.5 mm too high, you will be able to
see the bottom PCMCIA row of pins clearly.


> > from visual inspection from the front, it should also be obvious if
> > the card has been inserted where the top row of pins has gone into the
> > bottom part of the connector or vice-versa.
> Visual inspection from the front looks good to me but is difficult to
> photograph with good light and correct focus.
> > If You Can See Pins You Got It Wrong.
> I can't see pins anymore.

you need to check top and bottom.  top looks good, bottom also needs checking.

> >
> > also, once inserted, place the anti-static bag *in between* the Card
> > and the MicroDesktop PCB.
> >
> Is this for anti-static purpose or to add a bit of stability?

although it has that effect, it's there to protect against possible
short-circuit.  the top of the MD is lacquered, and there are no
components, however why take the risk?

anti-static means that when handling - inserting the bag - you don't
zap anything.

> Do you fold your bag to fit the entire length of computer-card?

nonono, that would put pressure on the PCB and bend the connector.
just slide it in gently in a U-shape.

> > you're better off checking with a multimeter.  it's pretty standard
> > (pin positive) however there is no substitute for actually checking.
> > i.e.: don't guess - check.  hardware is unforgiving.
> >
> Bought a multimeter and checked. DC PSU is good to go.

staaaar :)

> > > Should we document this somewhere on rhombus-tech.net?
> >
> > yes, good idea.
> Will do it in next couple of days.
> > > 4. SD-card ready / U-Boot
> > > Tried to compile u-boot-sunxi [4] and make exits with "System not configured".
> > > So Luke, what did you use as config
> >
> > it's on the wiki somewhere.  it has been 5 years so i will be
> > searching just as much as you would be.
> Ok.

there should be some a20_defconfigs... sitemap...  arse.  no, let's
try the git repo instead...


there you go.

> After a quick check it seems one can not create subpages from the online
> editor (only edit pages).

yes, this is standard practice.  you create the link on the parent,
first, then it creates a question-mark, then you get an edit link.  if
you know what you're doing you can manually create edit links :)

> Can I still send you an ssh-key to get a better access to the wiki?

sure.  that would help you as well as you can use "find" etc.

in case it wasn't obvious, thank you for this. pablo.  i really
appreciate you taking the time to get this sorted.


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