Coma Mode
Ubu King
be activated by pressing ON-SPC.
Maybe some of you programmers can tell me what it is, and
for which purpose can it be used. Can I, for example, turn
off the screen of the HP while running a long program (a
sort of screen saver)?
If yes, please tell me how to write it in RPL or SYSEVAL.
Thanx a lot.
Dave Arnett
I'm not a programmer, by any stretch of the synapses. But
I hope my hardware-oriented explanation will do.
There are four basic hardware modes for the HP48: Run,
Light Sleep, Deep Sleep, and Coma.
You are in RUN mode when the machine is actively executing a
program, making a calculation, or interpreting and handling
keyboard input. The machine is fully active (except, perhaps,
some hardware associated with communications and cards).
You are probably in LIGHT SLEEP when your display shows a
stack and no active command line, and you aren't executing
a user program. For most foks, the majority of time with the
calculator ON is spent in Light Sleep. The display is active,
as are some power supplies, keyboard scanning, and the clock.
But the CPU and anything else we thought was not immediately
needed sit idle. This is to decrease power consumption.
DEEP SLEEP is what most people call OFF. The clock is still
running, and the display driver is lucid enough to show an
active alarm annunciator. Most everything else is idle.
COMA is a mode few people think of in any usable context.
The Coma mode is the result of a group of Engineers with
a serious fixation on doing useful stuff with minimal
power drain. In Coma mode, all clocked activity is halted.
If you are familiar with CMOS logic power issues, you will
understand that the only power drained from the battery
is the leakage current across the bulk capacitors and the
transistor gate capacitors, which is darn near zero. Yet,
the contents of all registers in the CPU, the RAM, etc. are
retained. This is the beauty of CMOS: as long as there is no
clock, and no new data, holding everything static requires
almost no power.
You get to Coma mode in one of two ways: (1) [ON]+[Spc] or
(2) removing the batteries. I recommend you use method (1).
Method (2) is a failsafe so you can retain data through a
battery change. Method (1) will also clear the Warm Start Log
(accessed by the command WSLOG). There is no normal way to
access COMA mode from a program. Even if you did, using
system calls, it isn't very usable. You cannot awaken from
Coma by any method other than pressing the [ON] key, which
initiates a warmstart. Of course, alarms will not work,
because the clock is stopped.
Once upon a time, all HP48 calculators were shipped from the
factory in Coma mode. Batteries were installed before packing
the calculator. Coma mode assured that, if the calculator sat
on a stockroom shelf for a year before you bought it, you would
still find fresh cells when you opened the package.
By the time production moved to Singapore, the product was
already selling so well, this was not a concern. Now, they
are usually shipped in Deep Sleep. The advantage is that
your clock comes to you accurately set to Singapore time!
I believe there is a program out there which will shut down
the display and its interrupt requirements while running
user programs. You'll have to ask someone else about the
specifics. Sorry!
Dave.
--------
I don't speak for HP when I post here.
Barak Amit
: I heard of a sort of "Coma Mode" in the HP48G/GX which can
: be activated by pressing ON-SPC.
: Maybe some of you programmers can tell me what it is, and
: for which purpose can it be used. Can I, for example, turn
: off the screen of the HP while running a long program (a
: sort of screen saver)?
: If yes, please tell me how to write it in RPL or SYSEVAL.
: Thanx a lot.
In coma mode ALL calculator activities are halt (including
real time clock) therefore it is impossible to use this mode
for display disable during program execution.
Some people claim it's main use is for saving battery life (never tried
it myself)
Cyrille de Brebisson
>I heard of a sort of "Coma Mode" in the HP48G/GX which can
>be activated by pressing ON-SPC.
>Maybe some of you programmers can tell me what it is, and
>for which purpose can it be used. Can I, for example, turn
>off the screen of the HP while running a long program (a
>sort of screen saver)?
>If yes, please tell me how to write it in RPL or SYSEVAL.
no. The coma mode is a special OFF used by the interuption who is the off use in verry low bat.
the differance betin it and the normal off is that it cut all cutable periferics (clock ..) and you've got an ON-C after.
it can't be use in programm.