TI-H: Re: Color backlighting
[Prev][Next][Index][Thread]
TI-H: Re: Color backlighting
i was just reading about lcds and a problem is the... shoot what was the
probem... ...oh boy i forgot let me check... ok so i can't find that
article i guess i'll have to rely on my basic common sense on this one. one
of the problems would be memory no matter what you do color and displays
take up a lot of memory no matter what you do. also color will be a major
problem on the power.
color LCDs use four screens one for light saying that the LCDs themselves
don't generate any light, then they do have screens for the primary colors,
it'd be worth a shot saying that that's how some screens for laptops and
flat screens work it's worth a shot.
hey that just game me a though would it be possible to just take out the
whole display and just plug in one of those screens from a portable TV?
those are either LCDs or digital right?, arn't too bad on the power although
you'd still have to have another power source (is you still want it to be
able to run for any amount of time) and you could keep the receiver so you
could also watch tv on your calc. umm... never mind just get a pda.
;-)
Bernard
----- Original Message -----
???: "David Knaack" <dknaack@genesis.genetech.net>
???: "TI Hardware" <ti-hardware@lists.ticalc.org>
????: Thursday, April 13, 2000 23:50
??: TI-H: Color backlighting
>
>
> A reqest for comments concerning the possability of
> creating a color backlighting system for the calculators.
>
> First, yes, I know its a silly idea, I persue it because
> hacking the calcs is amusing, not because I think it has
> any inherent value. Its interesting to see just how far
> beyond its original design you an push a system. So don't
> worry about it if you think its stupid, I'm only interested
> in your opinion if you have input on the technical aspects
> of implimenting it (suggestions, possable difficulties,
> etc), or you wish to participate in software or hardware
> development.
>
> I don't know much about the grayscale routines in the
> calculator. This all makes the assumption that it would
> be possable to have 3 or 4 seperate screens, or color
> planes, which can each be shown for an interval. (??)
>
> First, a fiber optic backlight panel is installed behind
> the LCD, and three LED's are used to illuminate it, red,
> green and blue. The LED's are driven by a microcontroller.
> The microcontroller can multiplex the LEDs such that a wide
> range of colors is produced (I'm aiming for a palette of
> around 256).
>
> Since timing between the color change and screen-flips
> is critical, the microcontroller must either have its
> clock syncronized to the calculator, or have a low-
> latency communication channel to the calculator.
>
> The clocks could be sycronized in two ways, either the
> microcontroller can be clocked off of the calculators
> clock, or the micro can use a regular ~10Mhz clock and
> replace the calculators RC clock circuitry.
>
> Option 1 is probably less intrusive, but does not provid
> a clock that is anywhere near as stable, and forces the
> micro to run at a fairly slow rate, which may degrade
> its ability to provide color mixing.
>
> Option 2 is probably more difficult to get working, and
> is more intrusive (requiring the removeal of the calc
> clock), but allows for a very stable and adjustable
> clock. This option also allows for the use of an
> accurate real-time clock on the calculator.
>
> Using a sycronized clock removes the need for a low
> latency communications channel, the color palette
> and timing info can be preloaded into the micro,
> and the calc program can then easily know when each
> color will be active.
>
> One possable problem would be with startup sycronization,
> where the calc would know when the micro was switching
> colors, but not which color was active. This could
> probably be worked around by careful counting of clock
> cycles.
>
> If the clocks are not syncronized, some form of low
> latency communication will be necessary so that the
> micro can notify the processer when the color will
> change (or the calc can notify the micro when to
> change the color). This could possably use a direct
> interface to the address bus, or possably an interrupt
> signal. I'm not clear on the options here.
>
> Without knowing more about how the display works,
> I'm not sure how color screens would be displayed,
> perhaps someone could give a few examples?
>
> If someone can explain how it would work, I can
> write a windows app to demonstrate the technique.
> This would be a preliminary step towards actually
> implimenting the scheme.
>
> later
> DK
>
>
>
References: