OV7670 image sensor data capture with Atxmega32E5 without using external FIFO

• With current configuration, this system sends 20FPS 80x60 grayscale image data over 3Mbaud serial stream. There is 3 byte preamble {0xAA,0x55,0xAA} to indicate the start of a new image frame. Computer software / other MCU can use those bytes to sync with the data stream.

• Utilises two EDMA channels, two event channels, two timers and one UART peripheral of the XmegaE5 microcontroller.

• Computer software is written in C++ using OpenCV image drawing / matrix functions.

• This project is heavily inspired by "Interfacing a cheap phone camera module to a PIC32 microcontroller" project by @mikeselectricstuff. Video link of that project is: http://www.youtube.com/watch?v=rQYByorpoFk Watch that video to get a better understanding of this project. I basically ported his ideas to lower cost / lower feature set 8bit microcontroller.

Video:

• Watch it from Vimeo: https://vimeo.com/113537523

Sample capture:

Board:

Hardware connections:

/------------------------------------------------------------------------------
/ PORTD.7    => UART TX (UART is configured as 3Mbaud)
/ PORTD.5    => CAMERA RESET 
/ PORTD.4    => CAMERA XLCK (Master clock)
/ PORTD.3    => CAMERA SIOD (I2C data)
/ PORTD.2    => CAMERA SIOC (I2C clock)
/ PORTD.1    => CAMERA HSYNC (Horizontal SYNC)
/ PORTD.0    => CAMERA VSYNC (Vertical SYNC)
/ PORTA.7    => CAMERA PCLK (Pixel clock)
/ PORTC[7:0] => CAMERA DATA[7:0] (Parallel data bus)
/------------------------------------------------------------------------------

Reference projects:

• Interfacing a cheap phone camera module to a PIC32 microcontroller" project by @mikeselectricstuff. http://www.youtube.com/watch?v=rQYByorpoFk

• Some of the I2C settings are coming from: http://www.rpg.fi/desaster/blog/2012/05/07/ov7670-camera-sensor-success/

License:

/------------------------------------------------------------------------------
/ “THE COFFEEWARE LICENSE” (Revision 1):
/ <ihsan@kehribar.me> wrote this file. As long as you retain this notice you
/ can do whatever you want with this stuff. If we meet some day, and you think
/ this stuff is worth it, you can buy me a coffee in return.
/----------------------------------------------------------------------------*/