Service Model
8901B
REG
SREG
ROM
RAM
Cm
Gm
Vm
mAm
ENm
Xm
Mm
Zm
I
nble
8A-6.
Schematic Diagram
Notes
(7
of
11)
DJGITAL
SYMBOLOGY
REFERENCE INFORMATION
Sequential Logic Functions (Cont'd)
Register-Array
of
unconnected flip-flops that form a simple register or latch.
Shift Register-Array of flip-flops that form a register with internal connections that
permit shifting the contents from flip-flop to flip-flop.
Read Only Memory-Addressable memory with read-out capability only.
Random Access Memory-Addressable memory with read-in and read-out
capability.
Dependency Notation
Control Dependency-Binary affecting input used where more than a simple AND
relationship exists between the C input and the affected inputs and outputs (used
only with D-type flip-flops).
Gate (AND) Dependency-Binary affecting input with an AND relationship to those
inputs
or
outputs labeled with the same identifier. The m is replaced with a number
or letter (the identifier).
OR
Dependency-Binary affecting input with an
OR
relationship to those inputs or
outputs labeled with the same identifier. The m is replaced with a number
or
the
letter (the identifier).
Address Dependency-Binary affecting inputs of affected outputs. The m prefix is
replaced with a number that differentiates between several address inputs, indicates
dependency,
or
indicates demultiplexing of address inputs and outputs. The m suffix
indicates the number of cells that can be addressed.
Enable Dependency-Binary affecting input which, when active enables all outputs.
When inactive opencollector and open-emitter outputs are off, and three-state out-
puts are at an external high impedance state.
When the enable input affects only certain inputs and outputs, they will be numbered
to indicate the logic connection.
Transmission Dependency-Binary affecting input which bidirectionally connects de-
pendent inputs and outputs.
Mode Dependency-Binary affecting input used to indicate that the effects of partic-
ular inputs and outputs of an element depend on the mode in which the element
is operating. The m is replaced with a number or letter (the identifier).
Interconnection Dependency-Indicates the existence
of
internal logic connections
between inputs, outputs, internal inputs, and/or internal outputs. The
rn
is
replaced
with a number (the identifier).
Comma-AND Function.
Slant-OR Function.
NOTE
The identifier
(m)
is omitted if it is one-that is, when there is only one depen-
dency relationship
of
that kind in a particular device. When this is done, the de-
pendency indicator itself
(G, C,
EN,
or
V)
is
used
to prefix or suffix the affected
(dependent) input or output.
8A-16
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