Letux Kernel

Camera

Table of Content

How to control the camera

Camera

The (optional) camera is a OmniVision OV9655 1.3 Mpix camera module. It is connected to I2C2 and powered by VAUX3 (set to 2.5V). Two GPIOs can control the camera: Reset (GPIO98, active 1) and Powerdown (GPIO165, active 0).

3.7 kernel

It uses the omap3isp framework and the mediactl tool as demonstrated by the camera-demo script.

Description needs to be provided.

getting a vga resolution output using the omap isp

Configure a path from the ov9655 through the OAMP CCDC and resizer to the resizer output

media-ctl -r -l '"ov9655 2-0030":0->"OMAP3 ISP CCDC":0[1], "OMAP3 ISP CCDC":1->"OMAP3 ISP resizer":0[1], "OMAP3 ISP resizer":1->"OMAP3 ISP resizer output":0[1]'

Set the formats accordingly:

media-ctl -V '"ov9655 2-0030":0 [UYVY2X8 1280x1024]' media-ctl -V '"OMAP3 ISP CCDC":1 [UYVY2X8 1280x1024]' media-ctl -V '"OMAP3 ISP resizer":1 [UYVY 640x480]'

Now play the video from the resizer output:

mplayer tv:// -vf rotate=2 -tv driver=v4l2:device=$(media-ctl -e "OMAP3 ISP resizer output"):outfmt=uyvy:width=640:height=480:fps=30 -vo x11

old 2.6.32 stuff

This all has been integrated into the ov9655 and gta04_cam drivers so that you just have to open and use

/dev/video0

grabbing a still picture (at 16 colors)

streamer -c /dev/video0 -b 16 -o outfile.jpeg

grabbing video (at 3 fps and 10 minutes duration)

streamer -q -c /dev/video0 -f rgb24 -r 3 -t 00:10:00 -o /home/jhs/outfile.avi

showing through mplayer on X11

mplayer tv:// -tv driver=v4l2:width=640:height=480:device=/dev/video0:fps=12 -vo x11
mplayer tv:// -tv driver=v4l2:width=1280:height=720:device=/dev/video0:fps=4 -vo x11

previewing video on the OMAP DSS

there are drivers, but we don't know how they work

Torch/Flash (optional)

  • chip is on board
  • not tested
  • no recommended LED available
  • no driver ported

Installation

You need to install a white LED and drill a hole into the case.

Note: either the CPU or the Camera can trigger a strobe.

Ambient light sensor (optional)

There is an optional ambient light sensor. This is sort of a low power, 1 pixel B/W camera.

Installation

A recommended photo transistor is the Vishay TEPT4400. The long end should be soldered to the pin nearer to ???? You also need to drill a hole into the case.

Driver

The TSC2007 driver also reads the ambient light level (range 0 ... 4095) and presents it as the second last field of

cat /sys/bus/i2c/drivers/tsc2007/2-0048/values