[Arm-netbook] tablet, microdesktop and laptop progress

Luke Kenneth Casson Leighton lkcl at lkcl.net
Fri Jan 9 08:35:24 GMT 2015

On Fri, Jan 9, 2015 at 8:16 AM, Simon Kenyon <simon at koala.ie> wrote:
> On 01/08/15 23:38, Luke Kenneth Casson Leighton wrote:
>> well... some good news, we have sponsors for both the 7in tablet and
>> also a 15in laptop, which is amazing!
>> the laptop we have chosen a 15.6in 1366x768 LCD because anything lower
>> than that (either in size or in pixel resolution) is no longer
>> properly fashionable, it appears, whereas i am surprised to find that
>> 15.6in 1366x768 LCDs are not only extremely popular (over 50,000 for
>> sale on panelook.com), but also their power requirements are far more
>> modest than one might expect: around 3.5 watts for the backlight which
>> is pretty incredible.
> 1366x768 is rather old hat at this stage.

 and low cost and low power.  1920x1080 LCDs more than double the BOM.

> given the project lead times would it not make sense to go for 1920x1080?

 not at all.  1920x1080 over RGB/TTL requires to push those 18-bit
parallel pins at around 250mhz; the cost of the conversion ICs is
enormous; i cannot _find_ suitable conversion ICs, and that *extends*
the lead times - significantly

 the important thing is to get a product out the door, and the sponsor
agrees with both the estimated pricing and the specification.  it's
what *he* believes that he can sell easily, based on his business
experience and prior sales records over the last few years, that
counts more than anything here.

>> the only downside of using 1366x768 is that it is above the limit of
>> 1280x800 set for EOMA68 in a 5.0in form-factor.  i am not going to get
>> massively unhappy about this, but the CPU Card has to remain *inside*
>> the unit as a non-user-removable part.  the hilarious thing is that
>> the ICubeCorp IC3128 will actually work!  i tested it yesterday and it
>> can run 1280x1024 at 60hz (if you set 8bpp - 3Red, 3Green, 2Blue).  i
>> find this to be very very funny.  a $USD 2 Quad-Flat Package processor
>> running in a 15.6in laptop.
> i assume that was just a test.

 no, it's what the $2 SoC is capable of.  there is an internal bus
bandwidth issue.  theoretically it should not even be possible to
achieve 1280x1024 *at all*.

 for things like 800x600 it easily has the bandwidth to do 32bpp.

> 8bpp would be of very little use to anyone.

 well, the alternative is monochrome.  this is a *$2* processor where
i have the unusual pleasure of being able to work _with_ the designers
and engineers, rather than be told by the marketing team what's

 look at the A33: it's reported as 1280x800.  that's the end of the
matter.  ingenic jz4775? reported to bbe 1280x720 and that's the end
of the matter.  the IC3128?  supposed to only be capable of
800x600 at 32bpp but i currently have it at 1280x1024 and i intend to
test 1440x900 and beyond, to see how far it can go.

 in the meantime there is always the EOMA68-A20 which _can_ do up to


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