In a
previous TI-Planet news, we figured out that there was a hardware difference between non-CAS TI-Nspire CX and TI-Nspire CX CAS.
Although both calculators are sharing the same screen board
(which is the mainboard as it does include the ASIC and NAND chips but programmed differently), a
FireBird_Color_MB_6422 we noticed that the keypad boards had different references:
- FireBird_Color_KB_EVT_4421 for the TI-Nspire CX CAS
- FireBird_Noncas_Color_KB_EVT_4421 for the non-CAS TI-Nspire CX
We were wondering what the interest of maintaining a separate production line for non-CAS TI-Nspire CX could be, since unlike previous models both keyboards are now the same on TI-Nspire CX.
To better understand what TI had in mind, let's just plug a TI-Nspire CX CAS screen board in a non-CAS TI-Nspire CX:
The TI-Nspire CX CAS OS doesn't want to start and shows you an
"unrecognized keypad" error message, confirming that there is some hardware difference between the non-CAS CX and CX CAS keypad boards.
Let's also plug a non-CAS TI-Nspire CX screen board in a TI-Nspire CX CAS:
This time no error message, but the OS does not boot and the calculator enters a reboot loop.
All this is weird...
We could think to a protection against
'case switching' but it's not much harder to swith keypad boards after switching screen boards.
It might be intended to counter temporary or permanent non-CAS to CAs modifications through OSlauncher or hwMod, although they've never been runned successfully on TI-Nspire CX.
Or perhaps simply that this has been kept for strange compatibility reasons with non-CX Nspire models which had different keyboards.
Source:http://tiplanet.org/forum/viewtopic.php?t=10390
