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

Pablo Rath pablo at parobalth.org
Fri Jul 10 07:59:07 BST 2020

On Thu, Jul 09, 2020 at 11:43:58AM +0100, Luke Kenneth Casson Leighton wrote:
> On Thu, Jul 9, 2020 at 11:28 AM Pablo Rath <pablo at parobalth.org> wrote:
> > 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?

Yes, looks even to me.

> 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.

I am extremely careful. I triple checked from all sides and especially
from the *underside* and there are no pins visible. I tried to take a
picture yesterday and today in good daylight, with and without camera
flash, with and without additional lighting but I can't get a usable
picture *between* the PCBs. I wish you could see through my eyes :)
I think we have to trust in my assessment. I am *very* confident that
the connection is correct. 

> > > 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.

Done like described above. 

> > >
> > > 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.


> >
> > > > 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...
> http://rhombus-tech.net/allwinner_a10/boot/
> AH!  GOT IT:
> http://rhombus-tech.net/allwinner/a20/boot/
> there you go.

Ah, yes. This is what I found and mentioned in my email. Thank you for
looking it up and confirming. Will give it another try.  
> > 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 :)

Thank you for the crash course. Worked... almost like... *magic*.
I have created a subpage under a20 and will put everthing there and we
can move individual sections later if necessary. 

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

It is kind of obvious but still nice when explicitly mentioned. :)

So the next and last step hardware wise is to solder the UART connection
to the micro desktop? Can I use standard pin headers?

kind regards

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