ii) Open the plastic switch cover
on
the base
of
the PX-8.
Fig.
2.4
iii) Press the push
button
reset switch near the
DIP
switch. The switch
is
co-
vered to present accidental resetting
of
the sub
CPU.
It
has a hole in the
top through which it
is
possible to push the switch. Do not use a conduc-
tive implement to push the switch,
or
one whose end can break
off
(e.g.
a pencil).
SW4
.~
0 0
1=
€])
0
0
ROM 2
ROM 1
Fig.
2.5
2-6
iv) Replace the cover.
Turn
the PX-8 over and switch the power back on. The
following message will then be displayed
on
the LCD screen:
SYSTEM
INITIALIZE
ENTER
DATE
TIME (MMDDYYhhmmss)
000000000000
Fig.
2.6
This display image
is
the same as,
that
displayed after system initialization
described in Section 2.2.5b.
The display shows the first
of
a series
of
questions. These set the date and time,
and
the organization
of
the memory.
The first question the display shows allows the date and time
to
be entered.
The expression:
MMDDYYhhmmss
shows the order in which the items have to be entered. The number
of
items
corresponds
to
the row
of
zeroes to the right
of
the message. The first zero
is
covered by a flashing block. This
is
the cursor, which
is
used throughout the
operation
of
the computer to show the position
of
the next character to be print-
ed.
It
can sometimes be moved by using the cursor keys which are the keys
marked with
an
arrow
on
the right
of
the keyboard. This movement
is
under
the control
of
either
an
applications program
or
the overall controlling pro-
gram
or
operating system which
on
the PX-8
is
called
CP
1M.
The use
of
CP
1M
is
discussed in Chapter 3.
In
this particular case only two
of
the cursor keys
are active. They are the right and left pointing arrows which allow movement
of
the cursor within the bounds
of
the row
of
zeros. By using these keys the
flashing cursor can be placed over
anyone
of
the zeros and when you have
chosen a particular position the value can be altered by pressing the appropri-
ate numerical key. The cursor then moves
to
the next position
to
the right.
The various letters correspond to the date and time as follows:
MM: month (e.g.
01
for January and
11
for November)
DD: day
of
the
month
YY: year (e.g.
84
for 1984)
2·7
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