Author Topic: Let's overclock Nspire to x2 or x4  (Read 17353 times)

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Offline critor

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Let's overclock Nspire to x2 or x4
« on: December 28, 2010, 07:48:22 pm »
Nover is an overclocking Ndless program for the TI-Nspire.


The overclock persists after turning the calculator on/off.
It is cancelled by a reset.

If you know what you are doing, there shouldn't be any problem.
TI has overclocked the Nspire with the 2.1 OS: calculations are around 2 times faster.


Nover lets you play with 3 parameters:
* Base frequency: 27MHz or 114MHz-300MHz (by steps of 6) - default is 180MHz in all OSes
* Base/CPU ratio: x2-x254 (by steps of 2) - default is x2 in all OSes (x0 can be set but seems to be the ame as x2)
* CPU/AHB ratio: x1-x8 - default was x6 in OSes 1.x & 2.0, and is now x1 in OS 2.1

Base/CPU ratio cannot be improved (but you can make your calculator 127 times slower if you want :p ).

Setting CPU/AHB ratio to x1 made my calculator around 2 times faster with time-consuming mathematical sequences calculations.


Base frequency is a problem.
I could increase it to 300MHz (with the original Base/CPU=2 and CPU/AHB=6, which means 150MHz for the CPU) without crashing the calculator.

But there is a problem with the screen which is quickly oscillating horizontally, and less often vertically.
(seems to be similar with some Ndless 2.0 bugs)

The screen is readable, so I could make the test: calculator is around 4 times faster!!!!!
Would be great if we could stabilize the display.

Strangely, the screens stops oscillating when you launch an Ndless program, and resumes oscillating when you quit it.

So the good news, is that it doesn't seem to be hardware problem.
It seems to be a problem either with Ndless, either with the OS.

In fact, any base frequency different than 180MHz  is causing the problem (even 186MHz and even frequencies lower than 180MHz).

Maybe that 180MHz frequency is used somewhere hard-coded by the OS...
Maybe there is a screen refresh rate that should be changed somewhere...


Going to release the program with the sources.
You'll have full control of the 3 parameters, and also shortcuts to set the 2.1 OS overclock, or to set the original overclock. (which should work even if the screen is unreadable)

If it doesn't work: just remove the batteries to force a reset.


The program is  in a releasable state.
I'm working on the ReadMe. (saying that it's not my fault if anything happen... just use the official 2.1 overclock, and nothing bad should happen)

Nover is only 10Kb large. OS 2.1 reduces your available space by more than 1Mb.
The choice seems simple to me! :P
« Last Edit: December 29, 2010, 10:49:07 am by critor »
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Offline calc84maniac

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Re: Let's overclock Nspire to x2 or x4
« Reply #1 on: December 28, 2010, 07:59:25 pm »
I believe that the screen oscillation is caused by the OS's idle loop, which sets the clock speed lower (I think it outputs 0x00145006 as opposed to 0x00145002 on the older OSes). So it can change the base frequency quite regularly if it is not already at 180MHz, which probably messes with the LCD driver's internal timing.
"Most people ask, 'What does a thing do?' Hackers ask, 'What can I make it do?'" - Pablos Holman

Offline DJ Omnimaga

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Re: Let's overclock Nspire to x2 or x4
« Reply #2 on: December 28, 2010, 08:12:00 pm »
Woah I was so convinced the Nspire could not go above 150 MHz. Awesome critor! This kinda reminds me that Casio FX-9860G program that let you speed up the calc processor, except that on the 9860G, it did not overclock it, it just allowed you to setup the CPU at its max speed instead of the downclocked 29 MHz.

It would be cool if it works in 84 mode too.

Offline calc84maniac

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Re: Let's overclock Nspire to x2 or x4
« Reply #3 on: December 28, 2010, 08:14:08 pm »
Woah I was so convinced the Nspire could not go above 150 MHz. Awesome critor! This kinda reminds me that Casio FX-9860G program that let you speed up the calc processor, except that on the 9860G, it did not overclock it, it just allowed you to setup the CPU at its max speed instead of the downclocked 29 MHz.

It would be cool if it works in 84 mode too.
CPU only goes up to 150MHz, it is base clock that goes up to 300MHz.
"Most people ask, 'What does a thing do?' Hackers ask, 'What can I make it do?'" - Pablos Holman

Offline DJ Omnimaga

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Re: Let's overclock Nspire to x2 or x4
« Reply #4 on: December 28, 2010, 08:20:53 pm »
Oh ok, what's the difference between both, though? ??? I'm not familiar with that stuff...

Offline critor

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Re: Let's overclock Nspire to x2 or x4
« Reply #5 on: December 28, 2010, 08:22:56 pm »
Default Base/CPU ratio is set to 2 and it seems it cannot be decreased.

So the CPU working frequency is half of the base frequency.

For exemple, your Nspire cpu is currently running at 90MHz, because your base frequency is 180MHz.
« Last Edit: December 28, 2010, 08:24:35 pm by critor »
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Offline calc84maniac

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Re: Let's overclock Nspire to x2 or x4
« Reply #6 on: December 28, 2010, 08:25:35 pm »
The base clock frequency divided by the Base/CPU ratio (which, as critor said, is from 2 to 254 in steps of 2) is the CPU speed. The base clock is likely used for timing by other parts of the device, too (such as the LCD driver, which seems to stutter if the base frequency is changed a lot)
"Most people ask, 'What does a thing do?' Hackers ask, 'What can I make it do?'" - Pablos Holman

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Re: Let's overclock Nspire to x2 or x4
« Reply #7 on: December 28, 2010, 08:27:24 pm »
Ah I see now, thanks for clarifying.

Offline critor

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Re: Let's overclock Nspire to x2 or x4
« Reply #8 on: December 28, 2010, 09:48:34 pm »
English readme is completed.

I'm translating into french now.

Should release on TI-Bank before you go to bed :p


Code: [Select]
+-----------+
| Nover 1.0 |
+-----------+
by X. Andréani
http://www.ti-bank.fr/912


1) Introduction:
   ------------

Nover is a program to downclock / overclock your TI-Nspire.
In theory, it can make it 4 times faster.
But you'll only be able to make it 2 times faster without any problems.

TI has overclocked the Nspire and made it 2 times faster with the 2.1 OS.
But unlike OS 2.1:
* Nover doesn't reduce dramatically your available free space (only 10Kb for Nover,
13-15Mb for the 2.1 OS -> free space is decreased by 1.5Mb when upgrading 2.0 -> 2.1).
* Nover doesn't install a downgrade protection
* Nover lets you use the overclock from OS 2.1 on previous OSes.

If you allready have OS 2.1, you can try to overclock more,
but you should only try if you are familiar with ocerclocking.


2) Hardware required:
   -----------------

Any TI-Nspire calculator.


3) OS required:
   -----------

Any OS supported by a Ndless 1.7 compatible kernel.

As of this date:
- 1.3.2438 (non-CAS) [Ndless 1.3]
- 1.3.2437 (CAS) [Ndless 1.3]
- 1.4.11653 (non-CAS) [Ndless 1.4]
- 1.4.11643 (CAS) [Ndless 1.4]
- 1.7.2741 (CAS & non-CAS) [Ndless 1.7 & Ndless 2.0]
- 2.0.1.60 (CAS & non-CAS) [Ndless 2.0]


4) Software required:
   -----------------

Nover has been built for the Ndless 1.7 kernel.
You need Ndless 1.7, or a Ndless 1.7 compatible kernel.

As of this date, you'll need:
- Ndless 1.3 for OSes 1.3.2438  & 1.3.2437
- Ndless 1.4 for OSes 1.4.11653 & 1.4.11643
- Ndless 1.7 for OS   1.7.2741
- Ndless 2.0 for OSes 1.7.2741  & 2.0.1.60 (still in development)


5) Usage & keys:
   ------------


   a) If you're not familiar with overclocking:
      ----------------------------------------

Press the [*] [Enter] to set the config from OS 2.1 (2 times faster).
Press the [/] [Enter] to go back to the original config from OSes 1.1-2.0.


   b) If you are familiar with overclocking:
      -------------------------------------

Nover lets you play with 3 parameters:

* Base frequency: 27MHz or 114MHz-300MHz (by steps of 6)
  default is 180MHz in all OSes

* Base/CPU ratio: x2-x254 (by steps of 2)
  default is x2 in all OSes (x0 can be set but seems to be the ame as x2)

* CPU/AHB ratio: x1-x8
  default was x6 in OSes 1.x & 2.0, and is now x1 in OS 2.1

Press [1], [2] or [3] to choose the parameter to modify.
Press [+] or [-] to increase or decrease it.
Press [Enter] to set your changes.


Base/CPU ratio can be set to x0, but it seems to be exactly the same as x2.
So this parameter cannot be improved.

Base frequency seems to be causing problems with the LCD refreshing,
when set to any value different than 180MHz.
The screen is quickly oscillating horizontally, and less often vertically.
It only happens after exiting Nover.
Running any "long" calculation or any Ndless program is temporarilly
stopping the oscillations.
So the problem seems to come from the OS idle loop, and might be hard to fix...

What a pity! 300MHz makes your calculator 4 times faster... :(


6) In case of difficulty:
   ---------------------

Your screen is oscillating or filled with garbage?

Restart Nover (if possible & necessary).
Then set one of the 2 official configurations:
- Press [*] [Enter] (x2 config used in OS 2.1)
- Press[/] [Enter] (x1 original config used in OSes 1.1-2.0)

If you cannot make this work, remove a battery for some seconds.
The Nspire should restart normally.


7) Problems/bugs:
   -------------

* Screen oscillations when base frequency is different than 180MHz (see 5.b)
Problem seems to be related to the OS.


8) Overclocking or not overclocking:
   --------------------------------

Although I've made by best, overclocking can be a dangerous thing as it makes
the hardware work in a non official way.
There is a possibility than some parameters values (or repetitive uses of those):
* do erase some of your data permanently
* do make your calculator unstable permanently
* do shorten your calculator life
* do damage the screen permanently
* do damage your calculator permanently
* and many other frightening permanent things

The fact that TI is using overclocking in the 2.1 OS should prove the (2x)
overclocking option is safe, but we can never be sure.

Overclocking your calculator with other parameters values than the one of the 2.1 OS
may cancel your warranty (if TI has a way to check this).

I am not responsible for what you are doing and if your calculator is damaged permanently.
Be sure to know what you are doing, or to ask for help/advices on TI calculator forums.


9) Licence:
    -------

GPLv2. Source code is included.
You may modify the source code according to the included licence.


10) Release history:
    ---------------

28.12.2010: 1.0 - initial public release


11) Thanks to:
    ---------
The TI-Bank community for their encouragements. ( http://www.ti-bank.fr )
The Omnimaga community for their encouragements.  ( http://www.omnimaga.org )
ExtendeD for Ndless 1.7/2.0.
Bsl for Ndless 1.3/1.4.
Calc84maniac for his analysis of the oscillating screen problem.


12) Contact:
    -------

Xavier Andréani
[email protected]
« Last Edit: December 28, 2010, 09:50:10 pm by critor »
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Offline apcalc

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Re: Let's overclock Nspire to x2 or x4
« Reply #9 on: December 28, 2010, 09:56:16 pm »
Very impressive, critor!

You are doing a great and fast job bringing new programs to the Nspire! :D


Offline critor

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Re: Let's overclock Nspire to x2 or x4
« Reply #10 on: December 28, 2010, 10:33:35 pm »
Thank you apcalc! :)

Just found a very strange thing with the screen oscillations problem.


It's becoming much worse when:
- the calculator is connected to a computer through USB
- a mini USB A plug is plugged into the calculator, even if the cable is not connected to anything else.

The screen is still oscillating (doesn't seem to be faster or slower), but is totally unreadable.
You cannot see the text oscillating...
It's not blank either... it's as if it was oscillating garbage...


Anyway, I hope all users are going to be happy with the "x2" official overclocking, and that advanced users will find a way beyond, without oscillations...
I have not tried all base frequencies values yet.
You might find a magic value...
« Last Edit: December 28, 2010, 10:34:28 pm by critor »
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Offline calc84maniac

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Re: Let's overclock Nspire to x2 or x4
« Reply #11 on: December 28, 2010, 10:40:22 pm »
Well, the OS idle loop waits for an interrupt before returning to the previous clock speed setting. I've tested before that decreasing the rate of the timer that normally causes interrupts also decreases the rate of the oscillations. Connecting USB will cause more frequent interrupts, which causes the screen oscillation to become worse.
"Most people ask, 'What does a thing do?' Hackers ask, 'What can I make it do?'" - Pablos Holman

Offline critor

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Re: Let's overclock Nspire to x2 or x4
« Reply #12 on: December 28, 2010, 10:54:08 pm »
Thank you calc84maniac for all your comprehensive & interesting advices.
You've been mentionned in the readme.

Release!
Nover: the 1st TI-Nspire overclocking program!
Make your 1.1-2.0 OS as fast as the 2.1 OS, and even faster if you dare! :P
http://ti.bank.free.fr/index.php?mod=archives&ac=voir&id=2098


Have fun.
Please report any problem/error.
« Last Edit: December 28, 2010, 10:55:45 pm by critor »
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Offline Silver Shadow

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Re: Let's overclock Nspire to x2 or x4
« Reply #13 on: December 29, 2010, 05:46:11 am »
AWESOME!!! :thumbsup:

Now all we have to do is find out how to change the LCD's timer.
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Offline apcalc

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Re: Let's overclock Nspire to x2 or x4
« Reply #14 on: December 29, 2010, 10:47:09 am »
One small issue:  this has to be built with the latest Ndless to be compatible with the touchpad keys.  Other than that, it works great! :)