Re: A86: BIG TROUBLE --- NEED SERIOUS HELP


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Re: A86: BIG TROUBLE --- NEED SERIOUS HELP




I'm sorry, but this has to be said.... Most of us experienced asm programmers 
know that all you need to undo a frozen or crashed calculator is to remove 
the batterries and either hold in or repeatedly press the ON button.  This 
will work if the calculator is not broken.  If your batteries are low then 
you need to replace them, that is sometimes the cause of a crash.  For those 
not experienced in z80 hardware please read below if interested:
	The TI-8x models (excluding the TI-89) all run off a z80 chip.  This 
chip has a builtin routine in it called an interrupt (there are actually 
several).  Most of the inportant interrupts run in the background regardless 
of the calulators state, this includes the detection of the on key.  When the 
on key is pressed the battery power is relayed to the calc and it will turn 
itself on, unless it is already on or out of batteries.  The only reason you 
should not get a normal bootup is if the calc has crashed due to a faulty 
program.  This has nothing to do with the batteries or anything else along 
those lines!!!  You remove the batteries and press the on key so that it will 
drain the processor of power.  When the processor is power drained, all of 
the registers will be zeroed out (sort of like computer RAM) and the system 
will do a special bootup from ROM (calc crashes are not permanent, because 
the ROM is permanent) and creates a new system copy in RAM, acting just as it 
it were reset.  This is no different then when you buy a new calculator and 
put batteries in it for the first time.  If indeed removing all the 
batteries, pressing the on button repeatedly, and putting good ones back in 
(the old ones if they are still good, or new ones if needed) does not help, 
then your calc has some internal problem, like broken hardware (which CANNOT 
be done by program).  Broken calculators are not what we specialize in, that 
is up to TI to do.
Thanx for listening, 
Tim Adkisson


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