HP 8672S Operating And Service Manual page 89

Service
Models 8672S/86720A
mCNTR
REG
SREG
ROM
RAM
mAm
Gm
Cm
Vm
Fm
Table 8-1. Schematic Diagram Notes (7 of 8)
DIGITAL SYMBOLOGY REFERENCE INFORMATION
Sequential Logic Functions (Confd)
Counter—Array of flip-flops connected to form a counter with modulus m (m is
replaced with a number that indicates the number of states: 5 CNTR, 10 CNTR,
etc.).
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
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 and multiplexing of address inputs and
outputs. The m suffix indicates the number of cells that can be addressed.
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).
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).
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).
Free Dependency—Binary affecting input acting as a connect switch when active
and a disconnect when inactive. Used to control the 3-state behavior of a
3-state device.
NOTE
The identifier (m) is omitted if it is one—that is, when there is only one dependency
relationship of that kind in a particular device. When this is done, the dependency
indicator itself (G, C, F, or V) is used to prefix or suffix the affected (dependent) input
or output.