Programmable OSD video output module

project description

The purpose of this project is to implement a text and graphic display solution that can be superimposed on the video. Currently, the display is normal alone. The entire project is based on the Arduino IDE, so you can get started very quickly.

The refresh rate of the screen reaches the PAL standard and the pixels are 120*96, which is sufficient for general use.

However, the overlay part requires additional debugging because it is related to vertical signal synchronization. Currently, vertical synchronization is solved through interrupts but horizontal scrolling will occur. Specifically, you can use the library in the attachment and match it with the AVR MCU. Because 5V is used, the entire system It is more convenient to use 8bit.

Instructions

Arduino's A2 input adjustment function can be used to adjust the brightness of the video

RSET adjustment, used to adjust vertical synchronization

Two switches, the upper switch is used to switch the synchronization signal source, one is the synchronization signal separated from the input video using LM1881, and the other is the synchronization signal generated using the D9 pin. The switch below is used to switch whether to use the input signal, that is, to superimpose the signal or to use the Arduino output directly.

References and documentation

Library used: https://code.google.com/archive/p/arduino-tvout/

Open source design page for the prototype: https://www.open-electronics.org/a-video-overlay-shield-for-arduino/

lib...zip This is placed under the Arduino folder

ardui....zip Tetris program made using this TV library

AVO....zip test program, with merged output code