New camera sensor SIV121C

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New camera sensor SIV121C

James Cameron-2
We have begun qualification of a new camera sensor SIV121C for
production of the XO-1.75 and XO-4 laptops.

Deployments using olpc-os-builder can pick up the new kernel via the
usual RPM dropbox mechanism.

Laptops fitted with the new sensor as a spare can upgrade just the
kernel.

The new sensor does a little bit better at low light levels, as a
result of a different analog to digital conversion method.

http://wiki.laptop.org/go/12785
http://dev.laptop.org/ticket/12785

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Re: New camera sensor SIV121C

Martin Langhoff
On Wed, Jun 4, 2014 at 9:38 PM, James Cameron <[hidden email]> wrote:
> We have begun qualification of a new camera sensor SIV121C for
> production of the XO-1.75 and XO-4 laptops.
...

> The new sensor does a little bit better at low light levels, as a
> result of a different analog to digital conversion method.

Nice!



m
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Re: New camera sensor SIV121C

Paul Fox-2
 > On Wed, Jun 4, 2014 at 9:38 PM, James Cameron <[hidden email]> wrote:
 > > We have begun qualification of a new camera sensor SIV121C for
 > > production of the XO-1.75 and XO-4 laptops.
 > ...
 >
 > > The new sensor does a little bit better at low light levels, as a
 > > result of a different analog to digital conversion method.

i noticed on trac that you're supporting the new sensor on 1.5.  for
replacement purposes?

paul
=---------------------
 paul fox, [hidden email]
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Re: New camera sensor SIV121C

James Cameron-2
On Fri, Jun 06, 2014 at 09:26:31AM -0400, Paul Fox wrote:

>  > On Wed, Jun 4, 2014 at 9:38 PM, James Cameron <[hidden email]> wrote:
>  > > We have begun qualification of a new camera sensor SIV121C for
>  > > production of the XO-1.75 and XO-4 laptops.
>  > ...
>  >
>  > > The new sensor does a little bit better at low light levels, as a
>  > > result of a different analog to digital conversion method.
>
> i noticed on trac that you're supporting the new sensor on 1.5.  for
> replacement purposes?

yes, that's my hope.  i'm assessing that now.

i've an XO-1.5 motherboard, display, and sensor stacked, and have been
fiddling with new bits in the sensor registers; output drive
capability select [1].

the XO-1.75 and XO-4 work best with 3mA for the pixel clock and "other
outputs", which are the data lines.  at 8.2mA there are occasional
corruptions from bright parts of a scan line to the rest of the line,
with the condition clearing for the next scan line.

the XO-1.5 works best with 8.2mA for both.  at 3mA the data is certainly
corrupt, at 5.6mA it is occasionally corrupt, and at 8.2mA it is
rarely corrupt.


references:

1.  siv121c-config CHIP_CNTR in
    http://code.coreboot.org/p/openfirmware/source/commit/3727/

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Re: New camera sensor SIV121C

James Cameron-2
On Sat, Jun 07, 2014 at 08:22:23AM +1000, James Cameron wrote:

> On Fri, Jun 06, 2014 at 09:26:31AM -0400, Paul Fox wrote:
> >  > On Wed, Jun 4, 2014 at 9:38 PM, James Cameron <[hidden email]> wrote:
> >  > > We have begun qualification of a new camera sensor SIV121C for
> >  > > production of the XO-1.75 and XO-4 laptops.
> >  > ...
> >  >
> >  > > The new sensor does a little bit better at low light levels, as a
> >  > > result of a different analog to digital conversion method.
> >
> > i noticed on trac that you're supporting the new sensor on 1.5.  for
> > replacement purposes?
>
> yes, that's my hope.  i'm assessing that now.
>
> i've an XO-1.5 motherboard, display, and sensor stacked, and have been
> fiddling with new bits in the sensor registers; output drive
> capability select [1].
>
> the XO-1.75 and XO-4 work best with 3mA for the pixel clock and "other
> outputs", which are the data lines.  at 8.2mA there are occasional
> corruptions from bright parts of a scan line to the rest of the line,
> with the condition clearing for the next scan line.
>
> the XO-1.5 works best with 8.2mA for both.  at 3mA the data is certainly
> corrupt, at 5.6mA it is occasionally corrupt, and at 8.2mA it is
> rarely corrupt.

turns out the XO-1.5 shares the USB clock with the sensor, at 48 MHz,
and this is way above the sensor maximum clock of 27 MHz.

so this siv121c camera sensor won't work on XO-1.5.

the siv120d on the other hand has a maximum clock of 48 MHz, so it
works.

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