Operating instructions
mistake by clearing the A register with the R.3SE'I: A
switch and then starting over.
When the computer
is
in the altomxtic m3de, the
o2erator must be very careful nt2t to aczidentally
lower the R-ZSET A switch. If he sh9uld lower it
accidentally,
branzh cammands wvl~ld n~t oporate
corre.2tly. The operator would proSably not kn3w of
the error he caused until the programmer reported
back to him that the run was confused.
Toggle. When referring to the toggle switches,
it
has become customary to use the term toggle as a
verb.
When used in this way,
it
means to move the
switch either up or down and immediately return it
to
its
original position.
Control Switches
A strip of switches along the bottom of the control
console,
and the SAVE
P
and RESET A switches just
described, give the operator manual control over the
central processor and certain functions of peripherals.
Eight of the switches are the pushbutton type that
require only to be pressed momentarily to be activated.
Three double-label switches are the rocker type with
two positions. For instance, the
AuTO/MANUAL
SWITCH
is
placed in the AUTO position by pressing
the end that
is
labeled AUTO and leaving that end
in the depressed position.
These switches, illustrated in Figure IV-4, are des-
cribed as follows:
PWR. ON,
Depressing the PWR ON pushbutton
turns on DC power to the central processor,
the control console, and the 400 card per min-
ute reader. The pushbutton
is
also an indicator,
for it lights when power
is
on.
PWR, OFF. When DC power is on, depressing
this pushbutton turns
it
off.
RESET ALARM, This switch
is
effective only
in the manual mode of operation.
Depressing
the pushbutton clears any existing alarm con-
dition. It turns off the alarm lights and resets
flip-flops so the central
processor can continue
operation. It does not clear up the cause of the
alarm.
LOAD CARD. This switch is effective only in
the manual
mode of operation. Depressing the
pushbutton initiates card reader action and
causes the reader to go through one load and
read cycle. It is used most often to load the
first card into memory during program startup
operations, If no card was on the sensing plat-
form.
it
moves one onto it. From there, the
card
is
read into mel-nory locations starting at
0000.
RESET
P.
This switch
is
effective only in the
manual mode of operation. Depressing the
pushbutton clears the
P
counter to all zeros. It
is
used most often to cause the
first
instruction
to address memory cell zero, and
is
normally
activated just before setting the
AUTO/MANUAL
switch to AUTO at the beginning of program
operation.
AUTO/MANUAL. This two-position, rocker-
type switch selects either the automatic or the
manual mode of operation for the central pro-
cessor. When the AUTO portion of the switch
is
depressed, the central processor
is
in the
automatic mode, and instructions are processed
in a continuous sequence under program con-
trol. When the MANUAL portion of the switch
is
depressed, the central processor
is
in the
manual mode, and the
progranl
is
executed only
one step at a time as the START switch
is
depressed. Setting the AUTO/MANUAL switch
to MANUAL during automatic operation causes
the computer to halt operations at the end of
the
instructiorl or word being executed. The
operator will recall that putting the central
processor in the manual mode causes the
PRIORITY alarm light to come on. The fol-
lowing operations can be performed only when
the
AUTO/MANUAL switch
is
set to MANUAL:
1.
Clear or set information into
a
reg-
ister with option switches.
2.
Clear alarm conditions with RESET
ALARM switch.
3.
Reset P counter with RESET
P
switch.
4.
Load a card manually using LOAD
Card switch.
5.
Transfer contents of
A
register to I
register
using A to I switch.
6.
Txchange contents of
A
and
Q
registers
using XAQ switch.
INST/WORD,
This
is
also
a
two-position, roc-
ker-type switch which is effective only in the
manual mode of operation. It determines the
length of the cycle of the central processor
during manual operations. When the INST por-
tion of the switch is depressed, the central
processor executes one
conlplete instruction
each time the START switch is engaged. When
the WORD portion of the switch
is
depressed,
only one word time is executed each time the
START switch is engaged. The WORD position
is used by the operator
during system startup
and shutdown.