AVR PAL generation
Short description of hobbyist project
    by Jakub Trznadel


"...Imagination is more important than knowledge.
Knowledge is limited. Imagination encircles the world..."
Albert Einstein

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Before we start...

The main goal of this project was to check possibilities of use the Atmel AVR microcontroler in tasks rather not usual for 8-bit microcontroler.

Ideas

There are many ideas I wanted to test with this project. Some of them are:

  • Video signal generation (tested, working)
  • Capacitor measurement (tested, working)
  • Audio noise cancellation (working on it)
  • Infra-red RC5 decoding (not tested by now)

    Although I've used to use Microchip PIC16 family of chip, this time I decided to use Atmel AVR microcontroler. There are few reasons of this decision:

  • AVR is faster than PIC16. Most of the instructions take only one cycle. That gives up to 16 MIPS on 16 MHz AVR. PIC16 used with this frequency got only 4 MIPS.
  • AVR's got multiplication unit. Well, at least some of them ;)
  • I can use my favourite GCC compiler on AVR. In fact, this is the only 8-bit platform that allows me to use it;

    I've used the Atmel ATMega8 chip overclocked to 17.734475 MHz, which is four times the frequency of PAL colour signal 4.4297125 MHz. For digital-analog conversion the R2R ladder was used;
    The PCB was made at home, using photochemical method


     

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  •  
    Topics:

    1.Ideas
    2.PAL
    3.Problems




      Dev-board


      Devboard - ATMEL zoomed




    Links:

    AVR PAL color bar
    SX/PIC Tetris

    AVR GCC
    AVR Studio
    ATmega8



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