Conference hydra::amiga_v1

    Hi Greg,
    
    I've just bought the Rombo RGB splitter for use with DIGIVIEW v4.0
    and the results are a terrific improvement over the plastic colour
    filters. The gizmo is about 4 inches square with a small flying lead
    with a phono plug attached for video input. There is a push button
    switch on top that allows you to select red/green/blue/BW. Also there
    is a joystick cable attached (possibly for automatic switching?) and
    a 25-way D-type plug which has a sticker over it that says "Feature
    connector".
    
    The unit is of flimsy construction with two trimmer-style knobs
    sticking out of one end to vary the colour saturation and the
    brightness. You'll also need a seperate 9V power supply.
    
    Despite un-appealing looks it has performed very well with the
    camcorder and Digiview but results were not as good using the
    still frame from the VCR, producing a dull picture with noticable
    lines across the screen. If you're using a frame grabber, though,
    you may find it gives a better picture. (How many colours does
    Vidi-Amiga give you?)
    
    As for building your own; it could be a lot cheaper if you really know
    what you're doing or on the other hand it could be a total disaster!
    Maplin electronics (I have phone no somewhere) supply an interseting
    little chip for a fiver that seems to be one of the building blocks
    of these gadgets. Its supposed to be able to break down a video signal
    into sync and colour signals. They do a data sheet on all their chips
    at 50p each so there may be the circuit you want in there.
    
    On a side-track:
    
    Does anyone know how digiview produces the signals to control
    digi-droid? I want to be able to use the Rombo thing automatically.
    
    Thanks,
    Barry.

    The Sunrize Color Splitter allows DigiView's AUTO mode to control the
    switching from RED to GREEN to BLUE. I believe I have a note somewhere
    about the smart cable that can be purchased to do it. Dunno about your
    particular brand though.

    I've just had a look inside my Rombo RGB splitter, which comes apart
    with minimum of pull on the two case halves without unscrewing anything
    or breaking any stickers (I did say it was flimsy!) and the magic
    component seems to be a chip called SONY 8H01 V7020. There also about
    4 other common 74LS series chips.
    
    The other chip I was talking about from Maplin is called LM1881.
    The catalogue says this about it :-
    
    The IC can extract the timing information from PAL, SECAM or NTSC
    encoded video signals having standard negative going sync and
    amplitudes from 0.5V to 2V. The IC outputs the composite sync,vertical
    sync ,burst/back porch timing and an odd/even field identifier. By
    changing the value of R2, non-standard faster horizontal rate video
    signals can also be stripped. The vertical sync output is produced on
    the rising edge of the first serration in the vertical sync period, but
    if the rising edge does not occur within the internally set period, a
    default vertical output is produced, permitting use with video games
    and home computers. The IC can be used as a master gen-lock; to provide
    timing references for the extraction of data on specific scan lines; to
    restore the original video waveform for remodulation or retrieve the
    colour burst and decode into R.G.B. components; or to identify
    individual scan lines in the video signal.
    
    Chip pin layout :-
                            ----------
           composite sync --|        |-- Vcc
                            |        |
    composite video input --|        |-- odd/EVEN field output
                            |        |
     vertical sync output --|        |-- reset
                            |        |
                   ground --|        |-- burst/back porch output
                            ----------
    
    Hope this helps,
    Barry.

    If you have access to a set of Motorola data books (many DEC libraries
    have them), the "Consumer Electronics" section of "Linear and Interface
    ICs" contains several video building block chips.  Check out TDA3301
    and TDA3303 "TV color processors", complete PAL/NTSC to RGB decoders.
    Also MC1377 and MC1378 RGB to PAL/NTSC encoders for those who wish to
    feed Amiga video out to VCRs, etc.

    Perhaps someone will design a circuit for those of us that aren't
    harware types :-)
    
    

    The smart cable that allows DigiView to control either the MicroSearch
    or SunRize color splitters is called the MicroSearch DV cable. 
    MicroSearch is at 713-988-2818
    

    The Memory Location in Wellesley, MA regularly stocks the MicroSearch
    DV cable.  I bought mine from there.
    
    dennis

    Where does it plug into the Amiga? And do you know what pins do what?
    
    The RGB splitter I have is by Rombo (I don't know if this is available
    in the U.S.) so the cable will probably be useless with it, therefore
    I need to know which port digiview controls and what signals on which
    pins, etc.
    
    Thanks for any info, (I know this is a tall order!)
    
    Barry.

    See topic 1746(.10), plans for a homebrew "Digi-Droid".  This is what
    DigiView expects to be controlling...