[Arm-netbook] EOMA68 card based on NXP i.MX7 (work in progress)

[Vincent]

Hi Luke,

Okay, it is good to see you on the same page when it comes to KiCad vs.
Altium. Also, I wanted to give the community the chance to respond to
this prior to making any design.

I highly appreciate your effort in creating the template version of the
i.MX7 design. I hope I can carry it on in your best interest without
touching anything of the critical stuff.

Do you by accident know how critical the layer stack-up is in terms of
material selection, e.g., in terms of using FR4 and having controlled
impedances by the manufacturer? For testing purposes etc., it would
certainly be much easier to use a manufacturer that happens to be nearby.

Also, I wanted to point out that the i.MX7 security manual is only
available under an NDA (one needs to sign up and request the file
download). I'm actually wondering why this is the case because the stuff
in there is not that special after all.

Thanks for summarizing all the other aspects (power profile, etc.).

Best regards,
Vincent

On 05/10/2017 09:25 AM, Luke Kenneth Casson Leighton wrote:
> On Tue, May 9, 2017 at 9:53 PM, Vincent <ml.eoma68 at eml.cc> wrote:
>> Hi everybody,
>>
>> Since this is my first post on this list, please allow me to get off my
>> chest a few things:
>>
>> - huge thanks to Luke for getting this project started
>> - me = funding a PFY laptop, eagerly awaiting for it to arrive ;-)
>> - me = working at a research institute, focused on hardware security
> 
>  hi vincent, nice to see you here on the list.
> 
>> What would be of interest to me is the following:
>> - How well the idea of having an i.MX7 card is received
> 
>  i like it - the more the merrier, especially if there are others making them.
> 
>> - How important the use of an open source CAD program is.
> 
>  debatable.  if they were up to scratch it would be more important.
> they're not up to scratch... so... *sigh*.
> 
>> I have access
>> to Altium and have used it beforehand. However, KiCad has made
>> significant progress since CERN is involved. Using KiCad would make it
>> easier for the community to modify the board but since soldering these
>> components by hand is impossible anyway, would there be any benefit in
>> having freely accessible design files?
> 
>  you pretty much summed it up.  do the best you can.  gerbers, export
> the PCB so it *can* be imported into libre design software (i believe
> someone has actually written a plugin for kicad so it can import
> altium in some way), and so on.
> 
>  but honestly, KiCAD simply is not up to the task.  you *will* end up
> in a world of pain.  firstly: you should not be considering
> re-laying-out the DDR3 tracks (unless absolutely necessary... and -
> see later - it's not necessary).  secondly, if there's a pre-existing
> Reference Board you should be using it and adapting your working
> strategy to that.
> 
>  basically it's all about making the absolute minimum number of
> changes.  this is *not* software.  each "test" you do costs $1700 to
> $2000 and takes around 2-4 weeks to make then another 2-4 weeks to
> debug.
> 
> 
>> - General interest in a tamper-resistant enclosure
>>
>> To make the development easier, it would be nice if Luke could provide
>> us (the community) with:
>> - proper drawings for the outline of his PCB
>> - PCMCIA connector type/enclosure and height requirements of PCB
>> - mechanical verification package (as order option on crowdsupply) to
>> provide a "getting-you-started" package for EOMA68 card developers;
>> possibly including: PCMCIA receptable, connector, enclosure, etc.
> 
>  as you're the first let's do this in an informal way that's
> convenient for me to do.  i've had a go at converting the sabre iMX7
> Reference Design over to EOMA68, and what i'll do is email you that
> once i've put all the (latest versions of) components into it.
> 
>  then, if you use mike's factory, he has all the parts, and is set up
> to ship internationally.
> 
>> Please let me know what you think. Also, please keep in mind that this
>> is a kind of fun project for me at work and therefore the time I can
>> spend on this is limited. Progress will be slow but I will be sending
>> updates to the mailing list.
> 
>  cool - understood.
> 
>  well, i'll try to make it easy for you by cleaning up the converted
> Reference Design.
> 
>  this is awesome! :)
> 
> l.
> 
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