TI-84 Plus SE, HW version M (IDK what ASIC that is), and a lot of soldering experience.
pimathbrainiac wrote:
TI-84 Plus SE, HW version M (IDK what ASIC that is), and a lot of soldering experience.
You should pop it open and take a picture of the ASIC, if you can. The resistors (as you can read from the color codes) are 2.4KΩ and 2.6KΩ.
*bump* My TI-84+ and TI-84+SEs all have TA3 ASICs, which are the ones that are practically impossible to do anything with. I tried anyway on the TI-84+SE that was "dead", and I have good and bad news. The good news is that it lives again; the bad news is that I snapped an ASIC pin, and now it runs at 6.5MHz in every speed setting. So we know they can be underclocked by disconnecting the rightmost pin. Smile
I can't bear Wink to look at the screen! The horror! Even my beloved mutt, Boo, covered his eyes with his paws when I showed him the pictures and read the warnings.

Here is one CEMETECH community member who won't be trying this at home. Surprised

Mea culpa!
Understandable, and thanks for that colorful description of your reaction (bare/bear notwithstanding Wink). I would recommend that most Cemetechians, even experienced solderers like myself, leave their calculators alone.
KermMartian wrote:
Although I can't cite my source on this, one person mentioned that many teachers actually like the slower graphing, as it makes students think about how the y value of a rectangular function (for example) changes as the x value increases. That's purely anecdotal, of course.


Speaking as a teacher, one of the things I try to get across to my students is that a calculator is not a magic "black box" that just somehow "knows" what a graph looks like. It has to plot it pixel by pixel, much like they did in middle school with little X,Y tables. I suppose seeing each pixel being slowly plotted might add to that understanding. (I've heard other teachers complain about the Nspire's fast multi-pass graphing algorithm that does not allow the user to see the pixel by pixel plotting.)

That said, I would prefer a faster calculator any day. I loved the improvements in OS 2.55MP, but found the sluggishness rather annoying.

I use Wabbitemu with a projector in class. When graphing, I frequently hit F8 (400% speed toggle) to hurry things along. The first time I do this, the students invariably respond with "Hey, how do we make our calculators go faster like that?" Why not simply put a speed toggle in the MODE settings?

I believe that students and teachers would gladly pay a few extra dollars for a faster calculator. The occasional student who still has an 83+ would certainly tell you that they wish theirs was faster.

Perhaps they'll eventually come out with a Gold Edition that has the eZ80 processor.

-wes
Wes, thanks for that insight clarifying and confirming what I heard at T^3. I think many of us around here would take it for granted that students would understand that the calculator draws a graph the same way they would by hand, just much faster. It makes perfect sense, though, that many students wouldn't make that intuitive leap or might not even bother thinking about how the calculator generated its graph, and that having the graph appear slower could help push them to that conclusion. Of course, if they had a faster processor, they could always just add a setting that makes it graph faster or slower, or make it graph slower by default and pick a button you could press to make it quickly finish the current graph. I'm glad you're using a community emulator, although I of course am always curious what I can add to jsTIfied to make it more attractive to teachers. Unfortunately, extra speed isn't an option at this point. Sad
KermMartian wrote:
It makes perfect sense, though, that many students wouldn't make that intuitive leap or might not even bother thinking about how the calculator generated its graph

I think you hit the nail on the head---most students have simply never thought about it.

KermMartian wrote:
I'm glad you're using a community emulator, although I of course am always curious what I can add to jsTIfied to make it more attractive to teachers.

I played around with jsTIfied a little just to see what it could do. I was curious how it would handle the whole ROM issue. Nicely done with that.

I teach in Nairobi, Kenya where our internet is reasonably okay, but not 100% reliable. I encourage the students to use web based technology outside of class, but for actual teaching in the classroom I tend to avoid anything web based, or at least have a backup plan if the internet is down at that moment. So for me, using jsTIfied in class is not a reliable option at this time. (Similarly, I use GeoGebra ALOT, but I use the offline installed version rather than the WebStart version.)

-wes
That makes perfect sense, Wes, and it's one of the main reasons I long avoid making (and using) webapps. However, making jsTIfied made the most sense for the particular project, for the sake of showing that something like that was in fact possible, and to provide a tool that wouldn't need to be installed.
when i run the speed test, it gives me output in the form of
1M
M
Done

what is that supposed to mean?
That means that you have MathPrint on. Try turning it off.
fortytwo wrote:
That means that you have MathPrint on. Try turning it off.
IF you're not familiar with that process, just go to [MODE] and choose the CLASSIC option. You can always switch it back to MATHPRINT after you run the speed test.
So a little bump to this. I ordered some parts from digikey and overclocked 2 83+se's for omnimaga's contest. they can be found here
http://imgur.com/a/IJgAw

Whats next. Make an OS patch that stops the Ti-OS from interfering with the setting. Make sure all external functions work, and finally set up a set of hot keys to arbitrarily change hot keys as long as the Ti-OS interrupt is running.

After I get that done I might offer overclocking services for a fee because its not a hard soldering job but if your not practiced its very easy to mess up. 0603 parts are small :/
Nice job taking this to the next level. Smile Now that's we're pretty confident with those values, it looks neater to have SMT resistors soldered in rather than the interchangeable through-hole resistors I used. Keep up the good work. Smile
I plan to I bought 1% resistors and there is still a noticeable variance in Clock speed, as shownby the fact that the calcs have the same value resistors on each and they are at 2 different speeds. A version of ALCDFIX that works for the higher clock speed if possible should be included in the OS patch but if it has to be a standalone program. And I intend to I love this kind of soldering puts my hand eye coordination to the test something video games seem to no longer do Razz
Bit of a bump, but wondering what the progress is? Is there any hope for the 84C?
tr1p1ea wrote:
Bit of a bump, but wondering what the progress is? Is there any hope for the 84C?
There's no particular electrical engineering obstacle to this getting done; the limitation is that I don't have the proper tools at my apartment, namely a good microscope for the soldering work. Until I get my hands on one or find myself with a half-hour at a lab that has one, I won't be able to demonstrate TI-84+CSE overclocking in action.
Managed to overclock my CSE!

Instead of trying to solder directly to the ASIC pins, I took the lazy route and replaced the 15mhz speed mode resistor with a potentiometer (to easily adjust resistor value and therefor clock speed) It looks absolutely ridiculous having a huge pot sticking out from the top of my calculator, but its totally worth it considering everything is much faster.

Basically, I removed the resistor labeled "R07D", tacked two wires to the pads, and soldered the other ends to a 5k pot. Here's a picture:


(click for bigger)

~23.5mhz is about how far I can go before the screen just shuts off, not sure whats happening there. Anything past about 22mhz has memory-related issues, though. The OS is noticeably faster and much more comfortable to use too Very Happy

I also did it to my ti84+se (TA2 asic), and supposedly got it to 30mhz (its what the cpu speed test said, I don't know for sure.) I tried on my regular t84+ (TA1 asic) but I bricked it, it boots and everything but freezes the moment the ram is cleared.. its a 48kb ram model if that helps. Don't have any pictures for either atm.

Also, this page has some good info on the specific pins, etc:
http://wikiti.brandonw.net/index.php?title=83Plus:Overclocking (it says t83+ overclocking, but it covers info related to the CSE too)
I think you might be the first success on this front! Nice work! =)
elfprince13 wrote:
I think you might be the first success on this front! Nice work! =)
Congratulations are definitely in order, as you are indeed (to my knowledge) the first to overclock the TI-84 Plus C Silver Edition. The potentiometer solution is an inspired one, and I like that you retain the ability to turn the calculator back to stock speeds. I'd be very interested in hearing more about this purported 30MHz overclock; I suspect you might have gotten lucky with your ASIC (which you said was a TA2). I'll have to check my TI-83+SE to see if that was a TA1 or TA2, as I'm intrigued by this possibility.
  
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