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Author Topic: TI Nspire CAS+ ---- Is it worth it?  (Read 38216 times)

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Offline Goplat

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #15 on: March 23, 2011, 04:30:27 pm »
Quote from: mikehill2003 on March 23, 2011, 01:33:27 pm
Unfortunately, as someone who enjoys taking things apart to learn how they work, I am still somewhat interested in the CAS+. Does anyone know if the OS is encrypted (on the NAND Flash)? Has anyone tried to directly dump the OS from it?
If the CAS+ is anything like the released TI-Nspire/TI-Nspire CAS, then the OS is encrypted but the encryption key is present in the second-stage boot loader, which is merely compressed (and we can easily decompress it).

However, I don't think anybody has tried to dump the NAND flash by means of hardware hacking; I didn't know that was even feasible.
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Offline mikehill2003

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #16 on: March 23, 2011, 04:47:41 pm »
Quote from: Goplat on March 23, 2011, 04:30:27 pm
Quote from: mikehill2003 on March 23, 2011, 01:33:27 pm
Unfortunately, as someone who enjoys taking things apart to learn how they work, I am still somewhat interested in the CAS+. Does anyone know if the OS is encrypted (on the NAND Flash)? Has anyone tried to directly dump the OS from it?
If the CAS+ is anything like the released TI-Nspire/TI-Nspire CAS, then the OS is encrypted but the encryption key is present in the second-stage boot loader, which is merely compressed (and we can easily decompress it).

However, I don't think anybody has tried to dump the NAND flash by means of hardware hacking; I didn't know that was even feasible.

Well, I don't own an Nspire CAS(+ or not) yet, so I can't say for sure if it is feasible on an Nspire, but it has worked just fine for me on many other NAND Flash chips. ;D

Give me a few minutes and I'll find a simple tutorial.

This guy used an xD card reader. Simple ('cause xD cards are raw NAND in an expensive package) but it works pretty well. xD cards are pretty useful because you can use them to make a second, removable NAND. (Warning: Because the card reader contains the NAND controller chip, not all card readers work.)
http://busydizzys.com/index.php/2010/12/24/reading-embedded-flash-chips-nand-tsop-without-removal

Soldering this stuff is somewhat difficult. A microscope, steady hand, and hot glue really help.
« Last Edit: March 23, 2011, 05:02:29 pm by mikehill2003 »
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Offline critor

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #17 on: March 23, 2011, 04:52:25 pm »
Quote from: mikehill2003 on March 23, 2011, 04:47:41 pm
Quote from: Goplat on March 23, 2011, 04:30:27 pm
Quote from: mikehill2003 on March 23, 2011, 01:33:27 pm
Unfortunately, as someone who enjoys taking things apart to learn how they work, I am still somewhat interested in the CAS+. Does anyone know if the OS is encrypted (on the NAND Flash)? Has anyone tried to directly dump the OS from it?
If the CAS+ is anything like the released TI-Nspire/TI-Nspire CAS, then the OS is encrypted but the encryption key is present in the second-stage boot loader, which is merely compressed (and we can easily decompress it).

However, I don't think anybody has tried to dump the NAND flash by means of hardware hacking; I didn't know that was even feasible.

Well, I don't own an Nspire CAS(+ or not) yet, so I can't say for sure if it is feasible on an Nspire, but it has worked just fine for me on many other NAND Flash chips. ;D

Give me a few minutes and I'll find a simple tutorial.


Interesting. I've got several CAS+ so I can take the risk.

But I've only got an EPROM programmer :(

The NAND chip is a ST NAND256W3A.
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Offline mikehill2003

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #18 on: March 23, 2011, 05:04:59 pm »
Quote from: critor on March 23, 2011, 04:52:25 pm
Interesting. I've got several CAS+ so I can take the risk.

But I've only got an EPROM programmer :(

The NAND chip is a ST NAND256W3A.

Thanks, I'll try to find a datasheet.

Okay, here is the xD card pinout
http://pinouts.ru/Memory/xd_card_pinout.shtml

« Last Edit: March 23, 2011, 05:29:05 pm by mikehill2003 »
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Offline bsl

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #19 on: March 23, 2011, 05:18:49 pm »
There is a photo of the inside of a CAS+ plus that I have been
wondering about for a year and a half:
http://www.datamath.org/Graphing/JPEG_NSpire_CASP.htm#memory
Is that white 30 pin J02 connector possibly the JTAG connector ?
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Offline mikehill2003

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #20 on: March 23, 2011, 05:22:00 pm »
« Last Edit: March 23, 2011, 05:28:54 pm by mikehill2003 »
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Offline critor

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #21 on: March 23, 2011, 05:31:01 pm »
Quote from: bsl on March 23, 2011, 05:18:49 pm
There is a photo of the inside of a CAS+ plus that I have been
wondering about for a year and a half:
http://www.datamath.org/Graphing/JPEG_NSpire_CASP.htm#memory
Is that white 30 pin J02 connector possibly the JTAG connector ?

Did you notice that there strangely 2 such white connectors on the older CAS+ I have?

http://www.datamath.org/Graphing/JPEG_NSpire_CASE.htm#TI-OMAP
http://www.datamath.org/Graphing/JPEG_NSpire_CASPG.htm#TI-OMAP
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Offline mikehill2003

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #22 on: March 23, 2011, 05:32:46 pm »
Those aren't for the keyboard?
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Offline critor

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #23 on: March 23, 2011, 05:35:06 pm »
Quote from: mikehill2003 on March 23, 2011, 05:32:46 pm
Those aren't for the keyboard?

J02, probably...

But what's the purpose of the J04 present on older CAS+?
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Offline bsl

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #24 on: March 23, 2011, 05:36:07 pm »
Yes , I did  - I just pick one photo.
Its interesting thats the one obvious connection inside the Nspire, that
to my knowledge no one has attempted ?
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Offline mikehill2003

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #25 on: March 23, 2011, 05:43:36 pm »
Wow! Thanks for pointing that out bsl! Looking at the CAS+ and CAS boards side by side, there are some large differences between them. Now I really doubt that the CAS+ can run a production OS.


Quote from: critor on March 23, 2011, 05:35:06 pm
Quote from: mikehill2003 on March 23, 2011, 05:32:46 pm
Those aren't for the keyboard?

J02, probably...

But what's the purpose of the J04 present on older CAS+?

I can't really tell from that photo where the traces lead.
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Offline critor

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #26 on: March 23, 2011, 05:44:00 pm »
Hm... I'm not good at soldering... Allready had problems with the dock connector.
And I'll probably be much worse at micro-soldering...

Bsl? You think you could try that?


Once we get at least one image of a CAS+ boot2 + OS, we may find software-ways for dumping all other CAS+ versions.
« Last Edit: March 23, 2011, 05:44:46 pm by critor »
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Offline bsl

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #27 on: March 23, 2011, 05:58:16 pm »
Its between a card reader or a JTAG connection.
I haven't done hardware stuff for a while.
The card reader is the direct approach, a JTAG connection would be the best way(If it can be done at all ?)
There is JTAG software out there already, I would have to read more about JTAG and trace runs on the board.
I think ExtendeD did a little work on this.
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Offline critor

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #28 on: March 23, 2011, 09:14:06 pm »
Quote from: mikehill2003 on March 23, 2011, 05:43:36 pm
Wow! Thanks for pointing that out bsl! Looking at the CAS+ and CAS boards side by side, there are some large differences between them. Now I really doubt that the CAS+ can run a production OS.


Quote from: critor on March 23, 2011, 05:35:06 pm
Quote from: mikehill2003 on March 23, 2011, 05:32:46 pm
Those aren't for the keyboard?

J02, probably...

But what's the purpose of the J04 present on older CAS+?

I can't really tell from that photo where the traces lead.

You might see better on this one:
http://www.datamath.org/Graphing/JPEG_NSpire_P.htm#PCB

A TI-XXXXXXXXXXX (basic TI-Nspire prototype), which seems to have a similar connector.
The connector is not soldered on final basic TI-Nspire.
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Offline willrandship

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Re: TI Nspire CAS+ ---- Is it worth it?
« Reply #29 on: March 23, 2011, 11:58:03 pm »
It looks like some of the dock connector traces hook to it, but I can't be sure. It might be an SD card host though! That would be so nice.....

I actually sent a TI-Cares email suggesting an SD card connector because of the decreased space from 3.0, and got a reply back saying they would forward my suggestion to the RnD department... :thumbsup:
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