Agilent Technologies 2712A Digital Symbology Reference Information, Schematic Diagram Notes 6

Model 8904A Service

Table 8-1. Schematic Diagram Notes (6 of 11)

DIGITAL SYMBOLOGY REFERENCE INFORMATION

Sequential Logic Functions

In Monostable-Single shot multivibrator. Output becomes active when the input be- comes active. Output remains active (even if the input becomes inactive) for a period of time that is characteristic of the device and/or circuit.

GOscillator-The output is a uniform repetitive signal which alternates between the

n J - - L n high and low state values. If an input is shown, then the output will be active if an only if the input is in the active state.

FFFlip-Flop-Binary element with two stable states, set and reset. When the flip-flop is set, its outputs will be in their active states. When the flip-flop is reset, its outputs will be in their inactive states.

TToggle Input-When active, causes the flip-flop to change states.

SSet Input-When active, causes the flip-flop to set.

RReset Input-When active, causes the flip-flop to reset.

JJ Input-Analogous to set input.

KK Input-Analogous to reset input.

DData Input-Always enabled by another input (generallya C input-see Dependency Notation). When the D input is dependency-enabled, a high level at D will set the flip-flop; a low level will reset the flip-flop. Note: strictly speaking, D inputs have no active or inactive states-they are just enabled or disabled.

+m	Count-Up Input-When active, increments the contents (count) of a counter by “m”
	counts (m is replaced with a number).
-m	Count-Down Input-When	active, decrements the contents (count) of a counter by
	“m” counts (m is replaced with a number).
-m	Shift Right (Down) Input-When active, causes the contents of a shift register to
	shift to the right or down “m” places (m is replaced with a number).
-m	Shift Left (Up) Input-When	active, causes the contents of a shift register to shift
	to the left or up “m” places (m is replaced with a number).
		NOTE
	For the four functions shown above, if m is one, it is omitted.
(Functional Labels)	The following functional labels are to be used as necessary in symbol build-ups to
	ensure rapid identification of device function.
mCNTR	Counter-Array of flip-flops connected to form a counter with modules m (m is re-
	placed with a number that indicates the number of states: 5 CNTR, 10 CNTR, etc.).

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