ECS 154A Lecture Notes - Lecture 7: Clock, Clock Signal, Leading Edge
7 Jul 2016
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Document Summary
Combinational circuits can be described by boolean expressions where the output is strictly dependent on only the. Lecture 7: latches inputs: sequential circuits depend not only on the current inputs, but also on the history of inputs, i. e. they have a memory. The history of inputs determines the state of the circuit. Examples: house alarm system that must be reset once it senses an intrusion, or a combination lock: latch = a circuit that has two stable states and can be used to store state information. Unlike the combinational circuits, the outputs of the latch are not uniquely determined by the current inputs. Present inputs present state next state type of circuit. For nor latch inputs (1,1) the later states become unpredictable. For and latch inputs (0,0) later states become unpredictable. State transition diagram for q and combinations of (s,r) (0, 0) (0, 1)
