Timer program for TI-Nspire
Kinewey
TI-84+ Timer App? You will make many math & science teachers VERY
happy if you can share!!
Nelson Sousa
extremely unreliable. Even if after getting timing right with some
process (a program, a geometric animation, etc), the rate would
decrease with time, making it useless.
Nelson
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Olivier A.
http://hackspire.unsads.com/wiki/index.php/Memory-mapped_I/O_ports#90090000_-_Real-Time_Clock_.28RTC.29
Of course the reliability won't be perfect, but I wouldn't describe it
as an "extremely unreliable".
The native clock of the TI-89 Titanium for example works quite well.
Kinewey, what is this TI-84+ Timer App? What would you want such a
time program to do exactly? We could probably write one.
-- Olivier Armand
Sean Bird
http://www.ticalc.org/archives/files/fileinfo/202/20211.html
There was a way to calibrate it. That was an interesting activity to do at the beginning of the year. The 83 would be really slow until calibrated.
Eric Findlay
There is nothing like this on the Nspire, and will not be since there is no user access to the CPU clock and, so far, TI has said they won't allow 3rd party ARM programs.
Anyway, it wouldn't work the same way, as the Nspire doesn't allow (to my knowledge) drawing to the screen. Even if you had access to the clock, due to the way programs and functions are run, you could probably only use it to measure how long a function/program takes to run.
--Eric
Lionel Debroux
> there is no user access to the CPU clock and, so far, TI has said
> they won't allow 3rd party ARM programs.
As a matter of fact, TI has allowed third-party assembly programs,
because parts of the OS (outside of the Nucleus code, that is) are still
written with little attention paid to security.
In the beginning of the '90s, the TI-81 and TI-80 OS were released with
an overflow on the TABLE, which enables, by entering data, executing
arbitrary code.
In the '00s, the number of holes in TI-68k OS wrt. writing to Flash
memory outside the archive area has been increasing over time.
In the end of the '00s and the beginning of the '10s, the Nspire
contains multiple vulnerabilities that make it at worst possible to
corrupt memory by doing basic operations, such as checking the
calculator's state over the link port (see the video I made at
http://www.youtube.com/watch?v=ADRih4IqtbM ), or at best to reliably
execute arbitrary code.
> Anyway, it wouldn't work the same way, as the Nspire doesn't
> allow (to my knowledge) drawing to the screen.
I/O capabilities are, indeed, the most salient reason why the BASIC of
the Nspire series keeps being inferior to that of the TI-68k series.
Lionel.
Eric Findlay
--Eric
Xavier Andréani
>as it violates the end user agreement set forth by TI
An end user agreement can be illegal too.
>Basically, you purchase and own the hardware, but the OS is lent to you by TI, and altering and/or disassembling it in any way breeches their copyright.
But even if it was the case, I can't see how it would breech a "copyright"...
It might be illegal, but it's much more complex than what's you're stating.
Xavier
> Subject: Re: [tinspire] Re: Timer program for TI-Nspire
> From: eagl...@duetsoftware.net
> Date: Tue, 14 Dec 2010 00:10:14 -0800
> To: tins...@googlegroups.com
Lionel Debroux
> > > there is no user access to the CPU clock and, so far, TI has said
> > > they won't allow 3rd party ARM programs.
> > What TI says they want is irrelevant ;-)
> > As a matter of fact, TI has allowed third-party assembly programs,
> > because parts of the OS (outside of the Nucleus code, that is) are
> > still written with little attention paid to security.
> >
> > In the beginning of the '90s, the TI-81 and TI-80 OS were released
> > with an overflow on the TABLE, which enables, by entering data,
> > executing arbitrary code.
> >
> > In the '00s, the number of holes in TI-68k OS wrt. writing to Flash
> > memory outside the archive area has been increasing over time.
> >
> > In the end of the '00s and the beginning of the '10s, the Nspire
> > contains multiple vulnerabilities that make it at worst possible to
> > corrupt memory by doing basic operations, such as checking the
> > calculator's state over the link port (see the video I made at
> > http://www.youtube.com/watch?v=ADRih4IqtbM ), or at best to reliably
> > execute arbitrary code.
> >
> >
> > > Anyway, it wouldn't work the same way, as the Nspire doesn't
> > > allow (to my knowledge) drawing to the screen.
> > I/O capabilities are, indeed, the most salient reason why the BASIC
> > of the Nspire series keeps being inferior to that of the TI-68k
> > series.
> illegal as it violates the end user agreement set forth by TI.
> Basically, you purchase and own the hardware, but the OS is lent to
> you by TI, and altering and/or disassembling it in any way breeches
> their copyright.
AFAICT, TI hasn't ever sued the dozens of persons disassembling TI-Z80,
TI-68k or Nspire OS, over the past 15 years. Not even USA citizens.
One of the reasons can be that the freedom to tinker is not illegal in
the first place. But another reason is that by unleashing more potential
than TI do themselves, people who disassemble TI's OS end up helping TI
selling calculators to fellow users and programmers, and thereby end up
helping TI making more money. Sane corporations don't sue their
customers, especially purchase-driver ones.
(I'm aware that there's less of a word-of-mouth aspect in countries
where schools buy calculators for whole classrooms. But word-of-mouth
did definitely exist for me in Europe, in 2000, and it still exists to
date.)
As you're aware, disassembling allows, among other things:
* creating hardware and software documentation - for the TI-Z80 series
and the TI-68k series (and obviously for the Nspire series...),
third-party documentation has wider scope than official documentation;
* removing so-called protections that merely cost extra code to
programmers and complication to users. The protections of the TI-68k
series were nullified 10-11 years ago, because there's a way to unlock
them that can't be fixed without hardware changes (which TI has
subsequently performed neither 2-3 years later on the V200 nor 4-5 years
later on the 89T);
* fix bugs - we do that too for our fellow users, and we don't ask TI to
pay us for doing their job.
For the TI-Z80 series, I know of at least seven unofficial patches,
among which a bug with series on older versions, and major bugs with
MathPrint on 2.53MP.
For the TI-68k series, among dozens of known bugs, we fixed crashers
that TI didn't bother fixing for many years, such as the trap #3 bug, or
a nasty problem that can occur when changing batteries, or contrast
routines destroying registers outside of the normal calling convention.
For the Nspire series, the community is not fixing their bugs... yet.
As a result of the work of people disassembling OS/firmware, platforms
are used in ways that the manufacturer did not envision when designing
them, or even condone in any way. And that is A Good Thing (TM): a
fraction of users act as producers and hone their skills.
Lionel.