Sequential Logic

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A Sequential Logic is a digital circuit where one or more outputs are boolean functions of multiple inputs and the history of the outputs. In contrast to combinatorial logic, a sequential logic requires memory to somehow feed the history of the outputs back to the inputs. Usually, for deterministic and reliable behavior considering internal latencies and propagation delays, a sequential logic is synchronous, that is the memory only change their content on the edge of a clock signal.

=Applications= Sequential logic, that is combinatorial logic combined with memory, is the base of Finite-state machines, Turing machines as well as digital computers.

=Sequential Rook Attack= As an further example, a sequential logic may perform the same task as mentioned in Combinatorial Attack and Defend Map, but with less gates in up to seven cycles - similar to the bitboard techniques like Dumb7Fill:

+---+                               +--+     |       | o--/64/-- empty(square) -/64/--| 64:1 |>|       |-o result reliable / otherwise processing after reset +--+    | Comb. |-o A8 is attacked by white rook from south ^        | Logic | +--+    |       | o--/64/-- wrook(square) -/64/--| 64:1 |>|       |-->--+ +-.+    |       |     |                                   ^      o->|       |     | /6|     |  +---+     |                                   |      |                v                                +--+           | |             |           |                                |    Latch     |<--+ reset o|             | +---^--+                                   |                                   clk

=See also=
 * Belle | Hardware Move Generation
 * Combinatorial Logic
 * FPGA
 * Memory
 * Pseudorandom Number Generator

=Publications=
 * Alan H. Bond (1987). Broadcasting Arrays - A Highly Parallel Computer Architecture Suitable For Easy Fabrication. pdf
 * Alan Clements (2005). Sequential Logic. pdf

=External Links=
 * Sequential logic from Wikipedia
 * Counter from Wikipedia
 * Shift register from Wikipedia
 * Linear-feedback shift register from Wikipedia
 * Cyclic redundancy check from Wikipedia


 * Finite-state machine from Wikipedia
 * Harry Porter's Relay Computer
 * Passport - Infinity Machine, YouTube Video
 * 1976 lineup: Klaus Doldinger, Curt Cress, Wolfgang Schmid, Kristian Schultze

=References=

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