Barone OSD

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BaroneOSD is a PAL video overlay impression WITHOUT additional hardware required (NO LM1881 Sync generator).

Use only 3 pin:

D1 (USART TX) used to pump pixel in the video connected with a 330 ohm resistor to D6
D6 (AIN0) Video in/out, connect here you camera or radio TX.
D7 (AIN1) 0.3V Voltage reference (you can use a partitor resistor)

This is the source code: Download


Some usefull links:

  • Baloon Overlay (Vienna Society)
  • AVR2004 COG by William Cooke

    It is possibile to use SPI ports to generate pixels, it is better but need some code work:

    void initPorts()
    // D2 is output D6 is AIN0, D7 AIN1
    PORTB=0x0c; // SS+MOSI, SS(slave select) MUST be kept high
    // all B port input
    DDRB|=0x04; // SS is active low, but with 1

    PORTD=0xff; // all on
    DDRD=0; // all D port input

    void initSPI()
    //enable the SPI port
    // in master mode
    // with phase on
    SPCR = (1<<SPE) | (1<<MSTR) | (1<<CPHA);
    SPSR = 1; // fosc/2 = 8mhz pixel clock


    DDRB|=0x08; //sink thru PB3/D11 exit from High impedance

    for (int x=0;x<NCHARLINE;x++)
    SPDR = tileset[screen[x]+y*NCHARTABLE];
    _delay_loop_1(2); // 2 *(1+2) = 6 cycle at 16 mhz
    //while(!(SPSR & (1<<SPIF)));