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Re: [cosmacelf] Re: VP550 on LP

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  • William Donnelly
    I couldn t find any info on PIN-8 (Play It Now), either. Perhaps it s lost to the ether. It s not a full spectrum of notes on the musical scale, and
    Message 1 of 7 , Mar 14, 2013
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      I couldn't find any info on PIN-8 (Play It Now), either.
      Perhaps it's lost to the ether.

      It's not a "full spectrum" of notes on the musical scale, and durations, and other musical possibilities,
      which is why the music played is a little (or a lot) simplistic: (?)

      "Music is encoded from sheet music with note pitch and duration being described with a single 8-bit byte.
      PIN-8 is structured so that unique measures need only to be encoded once and can be used in any sequence.
      The amplitude envelope of a note can be controlled to have one of 16 values for each of 16 time segments of a note’s duration."

      There are only 12 notes on the chromatic scale. So you could get 4 more aditional notes above or below an octave,
      perhaps Middle C. Or you might use one as a non-sound rest. Any minimally complex music spans octaves, usually,
      so there might have also been some Up/Down shift commands, which one of the four could also be used for.

      Off hand, I would maybe set them to be: 0 = rest; 1 = Shift Octave Up; 2 = Shift Octave Down; 3 = Set Octave to Middle C

      And then you could do something similar with the 4-bit duration nybble, too. Depending on how many durations you want
      to support. Minimally, it would probably be 1/16, 1/8, 1/4, 1/2, and Whole. So, unless you want to play some "fancy"
      music (1/32 and some other things like that -- it gets REALLY 'complex'), you have some extra coding available there, too.

      Here's some 1802 (? -ish?) software I didn't know about: (CHIP-8-based, which I believe works on other CPU's, too)


      MegaChip8 devkit (2007)

      I will encourage anyone willing to attempt CHIP-8/SUPERCHIP/MEGACHIP8 development.

      This devkit will provide you with everything you need to start developing games:

      This Devkit contains everything you need to start Chip-8/SuperChip/MegaChip8 development

      - The Super/Mega/Chip-48 Assembler V2.5 by Christian Egeberg (MegaChip8 extensions by: M. Wenting / Revival Studios)
      - MegaChip8 specifications/documentation, full opcode list for CHIP-8/SuperChip/MegaChip8.
      - CHIP8_BMP.EXE - Convert BMP images to CHIP8-Assembler include data.
      - CHIP8_WAV.EXE - Convert WAV files to CHIP8-Assembler include data.
      - Small MegaChip8 example sourcecode.


      The devkit is available from the download section of the website.

      And there is some more interesting stuff there, too.

      – Bill

      On 3/14/2013 5:12 PM, urrossum@... wrote:

      > A few tunes recorded from a Cosmac computer. Sounds pretty good too.

      I'm not sure about sounding all that good - the intonation isn't particularly good, but the amplitude envelope is a lot less "bleepy" than I'd expected.

      I'd like to find out more about that PIN-8 music language - that's some pretty serious compression, encoding both pitch and duration into a single byte. Does anyone have any more documentation about it (my Google Mojo wasn't good this time)?
      Mark Moulding

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