Color NTSC video directly from an AVR chip

color-ntsc-from-avr-chip

We’ve seen composite video out from AVR chips many times before. But we can’t remember coming across one that managed to produce a color signal. This project does just that, producing a color video signal from an ATmega168 without using external integrated circuits.

[CNLohr] is seen here showing off his accomplishment. You’ll remember him from the glass-slide PCB server project he’s been working on recently. This time around it’s a small piece of gaming hardware which he’s working on. But using four pins from the microcontroller, connected via resistors in parallel, he is able to generate a color NTSC signal without using a chip like the AD723.

After the break you can see the two minute demo in which he shows the game running for just an moment, then gives a general overview of how the signals are being built. There isn’t a ton of explanation, but he did post his code as well as a resource for you to teach yourself more about the NTSC standard. Maybe you can make a color version of that AVR tetris game?

[via Reddit]

Comments

  1. Color me impressed!

  2. Awesome idea, loved it.

  3. Well, this has already be done 3 years ago ;)

    http://www.linusakesson.net/scene/phasor/index.php

  4. Trav says:

    sweet, I like it. Just about my hardware level. Now if I could get my coding skills up there.

  5. Douglas Bouttell says:

    You obviously have a very short memory. Linus Akesson did PAL on a ATMega88 http://www.linusakesson.net/scene/phasor/ in 2010

  6. zibri says:

    I wonder when will someone come out with HDMI and DVI :)

  7. Sam says:
  8. stevetronics says:
  9. rj says:

    Heh, he’s using the same analog stage as the Atari 2600.

  10. Protolamer says:

    I like his voice.

  11. biomed says:

    The old APPLE][ did a nice job of color NTSC. A few peeks at those schematics OUT OF THE 80's from a few geeks IN A GARAGE would help anyone taking a shot at this. For some truly serious good hacking though, take a look at the beautiful state machine they used to create the controller card for the DISK ][. The elegance was phenomenal.

    We need more such garages. Hackerspaces aren’t anything like that garage.

  12. Mateusz says:

    Uhm, OT, but what’s this whiteboard he has in his hand, and why it looks like USB-connected? :) Or is it just a sheet of paper glued to a laptop or something? :)

  13. alxy says:

    Atmega168 Max Operating Frequency: 20 MHz

    “This requires a 28.636 MHz Crystal!”

    Hmm.

    He also goes on to say:
    “This can be done even easier by using a PWM output signal. ”
    Does PWM even work on an overclocked avr? For sure ADC and eeprom is not going to work.

    • Charles says:

      I actually use eeprom and the ADC on another project overclocked the same without any issue. But, my sample size is small. It may be flaky and I don’t know it. The PWM CERTAINLY works, though.

  14. jonam says:

    Here is a PAL version done a long time ago:

    http://www.rickard.gunee.com/projects/video/pic/howto.php

  15. Marcus says:

    Here is a very powerful full color NTSC video generator running completely in a single AVR chip. Even 4 channel stereo sound!

    http://avrcade.com

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