====== VideoOverlayShield ======


The VideoOverlayShield is an Arduino compatible shield board that overlays text on analog video, using the Maxim MAX7456 on-screen display chip.

==== Overview ====

Product information: http://lowvoltagelabs.com/products/videooverlayshield/

==== Documents ==== 

  * Schematic and layout files in gEDA format (zip file): http://lowvoltagelabs.com/wp-content/uploads/2010/03/vos_v1002.zip
  * Schematic v10.02 in PNG format: http://lowvoltagelabs.com/wp-content/uploads/2010/03/vos_schematic_v1002.png
  * Layout in PNG format: http://lowvoltagelabs.com/wp-content/uploads/2010/03/vos_layout_v1002.png
  * Bill of materials: http://lowvoltagelabs.com/wp-content/uploads/2010/11/VideoOverlayShield_BOM_v1002.html
  * MAX7456 datasheet from Maxim: http://www.maxim-ic.com/quick_view2.cfm/qv_pk/5516

==== Getting started ====

The connections to the MAX7456 are as follows:
Arduino pin	 Software pin	 Maxim IC pin name
J3, pin 1	8	Video LOS signal
J3, pin 3	10	MAX7456 chip select
J3, pin 4	11	MAX7456 serial data in
J3, pin 5	12	MAX7456 serial data out
J3, pin 6	13	MAX7456 serial clock


The software pin definitions are: 
<code>
#define DATAOUT 11        // MOSI
#define DATAIN  12        // MISO
#define SPICLOCK  13      // serial clock 
#define MAX7456SELECT 10  // serial select
#define VIDEOLOS 8        // video loss detection
</code>

There is a thread on the Arduino forum that has software for using the MAX7456 with the Arduino. I've used this exact software with this board and it works great. 
The thread is here: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1220054359/all