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: VideoOverlayShield
Documents
- Schematic and layout files in gEDA format (zip file): vos_v1002.zip
- Schematic v10.02 in PNG format: vos_schematic_v1002.png
- Layout in PNG format: vos_layout_v1002.png
- Bill of materials: VideoOverlayShield_BOM_v1002.html
- MAX7456 datasheet from Maxim: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX7456.pdf
Getting started
The connections between the Arduino and the MAX7456 are as follows.
| Arduino Pin | Software Pin | MAX7456 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:
#define DATAOUT 11 // MOSI #define DATAIN 12 // MISO #define SPICLOCK 13 // serial clock #define MAX7456SELECT 10 // serial select #define VIDEOLOS 8 // video loss detection
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