Epson PX-8 User Manual page 20

2.2.2 Switching the PX-8 on and off
The PX-S has a power switch on the right hand side (see fig 2.3) which is the
normal way the computer is switched on and off at the beginning and end of
a session of using the PX-S. However, the PX-S is not switched off completely
as a mains operated computer would be if the power was turned off. The pow-
er switch can be thought of as a means of temporarily halting the operation
of the computer, so that the batteries are conserved. As soon as the power is
turned on again it is possible to begin exactly where you left off, even if you
were in the middle of typing a word or running a program.
The power switch is not the only means by which the power can be switched
on and off. The power switch of the PX-S is controlled by the computer, and
can and is switched off under software control. Thus, if it is not used for a
length of time (which can be set by the user using the CONFIG program
described in Chapter 3), it will switch itself off to conserve power. The user
can also program the computer to switch itself off at specific times. Further-
more the PX-S can switch itself on, run a particular program and then switch
itself on again to run the same or another program. This ability to switch itself
on and off is a powerful feature of the computer.
To switch the power on when the switch is already in the on position, switch
it off and on again. This means, holding the computer with the keyboard nearest
to you, moving the switch towards you and then away from you again.
To switch the computer off when it is already in the off position, switch the
power switch to the on postion and then off again.
Because the computer can switch itself on and off, the power switch position
may not reflect the true state of the power. For example if the PX-S switches
itself off, the power switch will still be in the on position, even
th~ugh t~e po~­
er is off. Similarly, if the PX-S switches itself on, the power sWItch wIll be m
the off position even though the power is on. Holding the PX-S normally with
the keyboard towards you, the power switch is on the right hand side of the
computer. The ON position is towards the back of the computer. The OFF po-
sition is towards the front of the computer.
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There are also two ways to switch the power off: the restart and continue modes.
The selected mode is determined by the conditions prevailing at the time the
power is turned off. When the power is switched off in the restart mode, the
Menu or CP
1M
command line display will be activated when the power is turned
on again. When the power is switched off in the continue mode, the operation
which is being executed when the power is turned off will be continued when
the power is turned on again.
i) Conditions under which the restart mode is selected:
- When the power switch is turned off.
- When system initialization is performed.
- When the sub-CPU is reset.
- When the BIOS POWEROFF r:outine is called. (See Chapter 5)
ii)
Conditions under which the continue mode is selected:
- When the power switch is turned off while pressing the
I
CTRl
I
key.
- When the auto power off time is reached, because no key has been
pressed. (See Chapter 3.)
- When the main battery voltage drops below a certain level
(power failure).
- When the BIOS POWEROFF routine is called.(See Chapter 5)
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