CaspaPX

The MT9V032 sensor at the heart off the CaspaPX is not yet supported in the kernel, so a little work is necessary to get the camera up and running.

Quickstart

The first steps are important to verify your hardware setup and so you know how to test your customizations later.

Pre-built Image

The easiest way to get started is to save these somewhere on your build machine and copy them to a COM running an existing image using scp.

Get the kernel and modules.

$ mkdir ~/caspakernel
$ cd ~/caspakernel
$ wget cumulus.gumstix.org/images/caspapx/uImage
$ wget cumulus.gumstix.org/images/caspapx/lib.tar.gz

Extract the modules.

$ tar -xf lib.tar.gz

Copy them to an Overo already running the image that you want.

$ scp lib/* root@overo:/lib/
$ scp uImage root@overo:/boot/uImage;
$ scp uImage root@overo:/media/mmcblk0p1/uImage

Reset the overo.

$ ssh root@overo 'shutdown -r now'

The easiest way to get the camera working is to download a pre-built image from here. Once your image has booted do one of the following from the serial console:

# export -DISPLAY :0.0
# gst-launch v4l2src ! xvimagesink

or

# mplayer tv:// -tv driver=v4l2:device=/dev/video0

Or you can open cheese:

<left-click on desktop> Applications > Multimedia > Cheese

Bitbake

If you want a more control over the packages included in your image, you can modify the bitbake recipe used to generate the pre-built image.

$ nano ~/overo-oe/org.openembedded.dev/recipes/images/caspapx-image.bb
  <make your modifications>
$ bitbake caspapx-image.bb

Customization

Hardware Overview

The OMAP35X processors have dedicated hardware for capturing and processing data from image sensors. The CaspaPX camera sensor outputs raw 10-bit Bayer images which is transfered to the Image Signal Processor (ISP) via a parallel interface. The ISP contains a previewer module that converts the Bayer data to YUYV. This data is accessible as a V4L2 device in /dev/video0.

Image Signal Processor

To get the best performance from the camera under other lighting conditions we need to get our hands dirty in the kernel source.

MT9V032 Driver

These steps will allow you to customize the camera driver and kernel for your own application.

2.6.34

Get the kernel source that is used in the Gumstix kernel recipe (~/overo-oe/org.openmebedded.dev/recipes/linux/linux-omap3_2.6.34.bb) and create a new branch from the recipe SRCREV.

$ cd ~
$ git clone git://www.sakoman.com/git/linux-omap-2.6.git
$ cd linux-omap-2.6
$ git checkout cb89736af28f583598e49a05249334a194d00f1d
$ git checkout -b 2.6.34

Make a copy of the default kernel configuration to use as a starting point for your customizations.

$ cp ~/overo-oe/org.openembedded.dev/recipes/linux/linux-omap3-2.6.34/defconfig ./
$ cp defconfig .config