OV9655

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OV9655 is an Omnivision 1,3 Mpixels sensor that can be found in the following commercial camera modules:

Connecting the OV09655-FSL module to the APF27

  • Datasheet of the OV9655 module are available here. They only detail the hardware interface.
  • Omnivision sensors are easily available but when it comes to obtain the datasheet of the sensor it becomes harder. Even if you find some datasheet, the informations inside must be read with caution: some are erronous. So here is one of those. For example RESET signal should be used the reverse way as indicated in the datasheets of the module.
  • This modules needs this Molex connector to be plugged in: http://radiospares-fr.rs-online.com/web/5426700.html.

Description

  • CSI port (8 bits data + 4 bits control signals) is used to transmit images. (10 bits mode not usable on i.MX). These signals are available on the APF27Dev J9 connector (2,5V logic).
  • I2C bus is used to configure the sensor. This bus is available on the APF27Dev J8 connector.
  • Sensor core power supply (1,8V) is derived from 2,8V of J9.

Adaptation board

  • (Preliminary) Schematics and layouts (Eagle) of an APF27 adaptation board are available here.
APF27Dev with OV9655 and LCD
OV9655_adapt montage (I2C cable: Blue on J8 pin 8 and Yellow on J8 pin 10)
  • BOM:
Components Quantity Ref.
Capacitor 100nF (package 805) CMS 4
MCP1700 1 MCP1700T-1802E/TT
pin header 1x2 male 2.54mm 3
Molex connector (for j9) 1 52437-2472
pin header 2x10 female 1 PPTC102LJBN-RC

Usage

  • Bring module out of powerdown by driving SSI3_TX (pin 30 of port C) as GPIO (through GPIOlib):
# echo 94 > /sys/class/gpio/export
# echo out > /sys/class/gpio/gpio94/direction
# echo 0 > /sys/class/gpio/gpio94/value; usleep 100000
  • Reset it by driving SSI3_CLK (pin 31 of port C) as GPIO (through GPIOlib):
# echo 95 > /sys/class/gpio/export
# echo out > /sys/class/gpio/gpio95/direction
# echo 1 > /sys/class/gpio/gpio95/value; usleep 100000
# echo 0 > /sys/class/gpio/gpio95/value; usleep 100000; echo 1 > /sys/class/gpio/gpio95/value
  • Load corresponding drivers:
# modprobe mx27_camera

Linux video capture interface: v2.00
mx27-camera mx27-camera.0: initialising
mx27-camera mx27-camera.0: Camera clock frequency: 33250006
mx27-camera mx27-camera.0: Using EMMA

# modprobe ov96xx

OmniVision ov96xx sensor driver, at your service
camera 0-0: Camera driver attached to camera 0
mx27-camera mx27-camera.0: mclk_get_divisor not implemented. Running at max speed
camera 0-0: Detected an ov9657 sensor
camera 0-0: Camera driver detached from camera 0

Test

  • You can then use Armadeus "capture" demo tool to get images from the camera.
  • First time you will have to set the camera module registers correctly (not done by the driver yet) by using a custom script ov9655_regs.sh available [ here]. Here is how to proceed:
# capture & usleep 400000 ; ./ov9655_regs.sh

Links