APPENDIX A
53B/53A/63A SYSTEM COMMANDS
Command D e s c r i p t i o n
@XY
T
h
e
@XY (Address) command addresses a function card in the 53/63 Series
System.
@ is an addressing delimiter used by the 53/63 Series System.
X is a mainframe address (0-9) defined by the address-select switch on the
53A-171 Control Card in the addressed mainframe.
Y is a function-card address (0-9) defined by the address-select switch on the
function card. Once a mainframe/function-card combination is addressed,
it remains addressed until the 53/63 Series System detects a
new
@
character.
@XS
@XH
STOP
The @XS (Status) command provides the interrupt status of all function cards
within the mainframe defined by X . T h e interrupt status o f all function
cards in the addressed mainframe is latched into the 53A-171 Control Card
when the @XS command is issued. A l l function cards i n all mainframes
become unaddressed after the @XS command is issued. T h e 53A-334 Card
does not have an interrupt mode and will never generate an interrupt status.
The 53A-171 Control Card Operating Manual describes the @XS command in
detail.
The @ X H (Halt) command halts all function cards within the mainframe
defined b y X . T h i s command does not affect function cards i n other
mainframes. H o w a function card reacts to the @XH command depends on
the particular card. The 53A-334 Card returns to its power-up state when it
is issued an @XH command. I n all cases, an addressed function card (Power
LED out) becomes unaddressed (Power LED lit).
The STOP command is not a string of ASCII characters. T h i s command is
hard-wired from the system controller to the 53/63 Series communications
card in each mainframe. When the system controller issues a STOP command,
each function card (including the 53A-334 Card) reacts as i f it had received
the @XH command described above.
How the system controller executes the STOP command depends on the
communications card used. For example, when using the 53A-128 IEEE-488
Card, a STOP command is executed whenever the system controller asserts the
IEEE-488 bus line 1FC (Interface Clear) true.
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