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CONSTRUCTION
OF OPERATIONAL
WORDS
General
Figures and
Letters as OWs
Delete Characters
as OWs
Operational Word
Memory Address
Assignments
CCM Initialization
•
Operational words are referenced by the CCM program primarily for
the determination of the presence of a specific character or character
sequence whic.h requires special handling.
OWs are accessed only upon
the recognition of a certain character that has been placed in the character
transfer store (LSW B).
An OW defines a specifiC operation or series of operations which the
CCM is required to perform under a certain setof circumstances.
Both
the operation and the condition under which they are to be performed are
established by the programmer duringCCM initialization.
It
is imperative,
therefore, that the programmer fully understand the functions and oper-
ation of the remote device or system to be controlled.
Parity is checked after a character has been placed in LSW B and before
the character is presented to the decoding matrix. Therefore, a bad parity
character would not be recognized by this decoding logic and would not be
detected as a character requiring an OW on those systems using parity.
The bad parity character, in this case, would appear to be just another data
character to the decoding logic.
•
The appearance of Figures and Letters characters in the processor
memory is controlled by the CCM in accordance with the reqUirements of
any particular system.
10
If
it is desired to discard these characters so that they do not appear
in processor memory, they must be designated for decoding and the
resulting OW-1 must indicate Ignore (bit 15 of OW-1 set to 1).
20 If
it is desired to allow these characters to enter processor memory,
no decoding and OW access is specified.
3.
If
it is desired that the program be advised upon the recognition of
a consecutive number or sequence of a particular character, desig-
nated for decoding then these incoming characters must be accessed.
A maximum of four consecutive identical characters can be utilized
in this case for the accessing of an OW for such control purposes.
•
It
is common for remote terminals which use USASCII to utilize the
Delete Character as a fill character similar to the use of Letters by re-
mote terminals operating with a 5-level Baudot code. USASCII Delete
recognition can be used to access an OW and be discarded when received
from the communication line.
If
CCM program recognition is arranged in
this manner, it will prevent these Delete characters from reaching pro-
cessor memory.
•
In advance of system delivery, a list must be developed of the control
character bit configurations to be recognized and the corresponding input/
output, in data block (NDB) , and Sequence Counter (LSW F15, F16) set-
tings which will result in th,e accessing of respective OW sO This inform-
mation is used to provide the instructions for the necessary factory
hardware wiring and advice as to the correct CCM memory address
locations for OW initialization. (Refer to standard RCA EDP Procedures.)
2-3
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