Author Topic: Weird Ports  (Read 5106 times)

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Offline Camdenmil

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Weird Ports
« on: June 17, 2011, 12:08:28 am »
I've noticed for a while that when I send 1C-1F to port 10 in calcsys, nothing happens. I tested this in an asm program and no blueness occurred. I also noticed that port 20 ignores bit 1. According to wikiti, port 20 has 4 settings and on a friends calc, sending 2 and 3 to port 20 acts like wikiti says it should. I have a ramless 84+SE and my lcd driver is 240 fps and it does support the mirring/flipping.
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Offline ralphdspam

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Re: Weird Ports
« Reply #1 on: June 17, 2011, 12:18:09 am »
No blueness?  No Nethams?  D:
Never heard of it before!

On the back of the calculator, between warnings and the battery cover, there should be an engraved number.  The advanced Asm programmers will be able to help/ask more questions.
« Last Edit: June 17, 2011, 12:18:29 am by ralphdspam »
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Offline calc84maniac

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Re: Weird Ports
« Reply #2 on: June 17, 2011, 12:27:58 am »
I've noticed for a while that when I send 1C-1F to port 10 in calcsys, nothing happens. I tested this in an asm program and no blueness occurred. I also noticed that port 20 ignores bit 1. According to wikiti, port 20 has 4 settings and on a friends calc, sending 2 and 3 to port 20 acts like wikiti says it should. I have a ramless 84+SE and my lcd driver is 240 fps and it does support the mirring/flipping.
I think the port 20h issue is the OS's fault. thepenguin77 encountered that too.
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Offline DrDnar

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Re: Weird Ports
« Reply #3 on: June 17, 2011, 12:48:36 am »
Obviously, TI is using slightly different LCD driver models. As long as they're not using the super-slow ones, I don't think we should really care. There's little point to screwing around with the test mode anyway. Incidentally, the blue lines of death only seem to work on the TI-83+.

By the way, I thought that the maximum theoretical bandwidth for the LCD drivers was more like 120 FPS. Do the new ones require less delay?
« Last Edit: June 17, 2011, 12:49:12 am by DrDnar »
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Offline ralphdspam

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Re: Weird Ports
« Reply #4 on: June 17, 2011, 12:56:46 am »
If there is less delay, does that mean better grayscale (if programmed properly)?
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Offline DrDnar

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Re: Weird Ports
« Reply #5 on: June 17, 2011, 12:58:11 am »
That's a good question. The Desolate guy remarked to me that experimentation showed that the LCD driver only updated the screen at 60 FPS. I've been meaning to write a program for precisely checking this.
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Offline thepenguin77

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Re: Weird Ports
« Reply #6 on: June 17, 2011, 01:00:48 am »
On my calculator, $1F is the only command that makes the blue screen of death occur. Just slightly different drivers.

The port 20h thing is caused by the OS like calc84 said. But actually it's caused by the OS executing hooks. I just looked at the code, and what the OS does, is when running the hooks, it sets the calculator in 6MHz mode. Then when the hook is done, it takes out the old port ($20) value and and's it with 1. That would be why it appears you can't set it to 3.

To prove my point. Turn your calculator off. Hold Left+Right and press on. Press clear. That just disabled all hooks. Now try it again in calcsys. You'll notice that you can now set 3.


And DrDnar. 120 FPS is the slowest the LCD drivers ever run. During my testing, I've seen K-Factor calculators hit 280 fps running >17MHz.

Edit:
    The desolate guy? http://ourl.ca/9538/182589
« Last Edit: June 17, 2011, 01:01:42 am by thepenguin77 »
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Offline ralphdspam

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Re: Weird Ports
« Reply #7 on: June 17, 2011, 01:05:54 am »
Is there a place with the specs of each factory screen?  (I guess it should belong on Wikiti or something.)
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Offline DrDnar

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Re: Weird Ports
« Reply #8 on: June 17, 2011, 01:08:26 am »
"The Desolate guy" is Patrick Prendergast, aka tr1p1ea. So, yes, the 60 FPS thing has been known since at least 2004.
« Last Edit: June 17, 2011, 01:10:23 am by DrDnar »
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Offline thepenguin77

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Re: Weird Ports
« Reply #9 on: June 17, 2011, 01:57:37 am »
Yeah, I know, who tr1p1ea is. I was just saying that I also found the same thing. The good news I guess would be that we both came up with the same conclusion :D He just did it long before I did.
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Offline Camdenmil

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Re: Weird Ports
« Reply #10 on: June 17, 2011, 02:35:28 am »
Uninstalling hooks makes port 20 work. Too bad everyone can't experience the lcd burning experience of test mode. Oh well, yet another hardware variation.
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