Glenn Saunders wrote:
>There are all sorts of wacky modes you can enable on the Atari by setting
>the mode to decimal points or really large values that seem to mix
>attributes from two or more modes into one.
>
>There is one mode that works like GTIA mode (16 shades of one hue) but you
>can type characters into it. But the characters come out two pixels by 8
>pixels in various shades of grey depending on the underlying pixel encoding
>of the characters. Very strange.
Well, I suppose the "indirection thing" that leads to character values will
work for all modes, including the one you mentioned, only that it won't be
of much use there... but the mode you mentioned could of course be of some
use for game designers.
I think every system contains bugs and easter eggs like these. I think the
manufacturers only documented the functions of their machines that made
sense to them and left the rest alone, but they have been used by some
people anyway. The 2600 alone is full of such things on which some games
rely (the HMOVE blanks, the duplication of players, the Cosmic Ark stars,
etc. etc.). On the C-64, for instance, you can combine the different
waveforms by writing other things into that area... and some of the
resulting sounds can be useful sometimes. On the TMS9918 video chip, you can
also do this... combine video modes, and I know at least of one game that
uses an undocumented mode (Boulder Dash on the TI-99), while I never managed
to come across documentation how exactly these modes work. I even found
undocumented things with my Yamaha and Technics keyboard having to do with
MIDI... you can switch the Yamaha into a mode where it accepts MIDI data for
multiple instruments on different MIDI channels. This mode is present on
most newer keyboards including my Technics, but not documented in the
Yamaha's manual. On the Technics, you can access more instrument sounds than
are documented, similar to those in higher models. Even if not all of them
sound the same as in higher models, at least many of them sound different
than those you would normally get out of the machine.
Aside from the graphics chip, there are undocumented features in the CPU's,
such as undocumented opcodes. It's somehow like turning the old Rubik's Cube
around and finding new, shorter moves. It was always one of the most
interesting things for me to find out ways you could use documented, or
undocumented, features to impress people with something that would be
undoable with that hardware normally. Did you, for instance, ever sing
Karaoke using the "Mic Mixing" input of a VCR (which is supposed for audio
dubbing)?
With love from Austria (and many undocumented features to find)
Kurt Woloch
--
Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/
