So, I was messing around with my calculator (attempting to manipulate appvars) when it crashed. This time, however, was different from all the rest: instead of having the screen clear, then turn off the calc, a single horizontal blue line appeared. It wasn't just a line of darkened pixels, no, this was a vivid blue color.
My question is, Is it possible to recall this shade and manipulate it to create bluescale?
This is a well-known phenomenon, caused by the LCD controller entering a state known as "test-mode", in which the LCD controller drives the LCD with abnormally high voltages. This happens when a particular command is sent to the LCD controller. The datasheet on the controller says, "Do not use this command." (It could, in theory, damage the LCD.) The answer is no, this cannot be used to create special effects, other than a blue screen. A trivial assembly program can invoke this effect on-demand, and end it on-demand. Calcsys can also do it.
Ah, okay. That makes sense.
It is possible to drive a monochrome LCD in such a way as to produce limited color.
Randy Compton managed to get color on his TI-86 as seen here:
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On the archived version of his website, he says this:
Site History and News wrote:
4/30/2005: Hmm...I tried to get the TI-86 COLOR program to display things other than bars.
This [dead link] was the result (the colors are barely discernable & cannot stack vertically), which leads me to believe that my goal is impossible (at least, by the method I tried). Oh, well. It seems that with proper coding one could get n-level grayscale & yellow at the same time (with black optionally replaced with blue), but not green & red. At least I can still bother people with the color bars demo. Someone mentioned that it might have something to do with the flicker of lights, but that is improbable, since the calculators refresh at 50Hz, while here in the USA power lines use 60Hz. Also, it works in sunlight, & I doubt the sun flickers at either frequency.
It's quite bad for the LCD as it puts it under a lot of stress, and it isn't very useful.
I recall a couple of programs which used this effect. One looked like a waterfall. Another was a color pong with I think a blue background with yellow paddle. So it's possible to do some crazy things with this, but you could damage the calc.
Certain programs just quickly flashed between lowest contrast to highest during about half a second to achieve lightning bolt effects. On the SE and 84+ calcs a rapid change from dark to light contrast resulted into the screen turning blue for like 0.001 seconds, so when doing it fast enough it produced a bluescale effect that is less intense and damaging than the well-known BSOD. It can still be pretty dangerous if abused, though.
CVSoft wrote:
It is possible to drive a monochrome LCD in such a way as to produce limited color.
Randy Compton managed to get color on his TI-86 as seen here: [snip]
I am with Kerm on this one. Another note is that bluescale could indeed turn into deadscale if you play with it too much.
One historical note is that somewhere in the UnitedTI archives on here, there is a record of someone respectable (I think DarkerLine?) experimenting with the potential for damage. They claimed they were able to run bluescreen programs continuously for 24+ hours without noticeable damage to the LCD. That said....the datasheet for the LCD says not to do it, so it's probably a good idea not to.
On my older 83+, I ended up with some darker spots in the screen (contrast-wise) after abusing bluescale, but on the 83+ it only displayed lines rather than filling the entire screen. I usually let it run into test mode for over a minute multiple times and other times for 10-20 seconds.
Well, we don't want to damage the LCD (and I especially don't, seeing as I have one calculator). Thanks everyone for answering!
