CS 120 midterm

Hierarchy

A system divided into modules/submodules

!B0 * !B1 * !B2 =

!B0 + !B1 + !B2

(B*C) + (!B*D) + (C*D) =

(B*C) + (!B*D)

code to run

./*name*

B * !B =

0

B * 0 =

0

B + !B =

1

B + 1

1

Discipline

Intentionally restricting design choices

2^30

about 1 billion

2^20

about 1 million (act 1,048,576)

2^10

about 1000 (actually 1024)

Register

bank of D Flip Flops, Used in finite state machines

code to compile

gcc *name*.c -o *name*

program used to remote access terminal

ssh

AND Gate

x y 0 0 0 0 1 0 1 0 0 1 1 1

XOR Gate

x y 0 0 0 0 1 1 1 0 1 1 1 0

OR Gate

x y 0 0 0 0 1 1 1 0 1 1 1 1

NOR Gate

x y 0 0 1 0 1 0 1 0 0 1 1 0

XNOR Gate

x y 0 0 1 0 1 0 1 0 0 1 1 1

NAND Gate

x y 0 0 1 0 1 1 1 0 1 1 1 0

(B*C) + (B*!C) =

B

B * (B+C) =

B

B * 1 =

B

B * B =

B

B + 0 =

B

B + B =

B

(B * C) * D =

B * (C * D)

(B*C) + (B*D) =

B * (C+D)

(B + C) + D =

B + (C + D)

Bistable circuit

Building block for other state elements (no inputs)

Regularity

Encouraging uniformity, so modules can be reused

Modularity

Having well defined functions and interfaces

Abstraction

Hiding details that aren't important

D Flip-Flop

Holds next value on edge, when clock goes from 0-1, the circuit lets out internal and takes in next, closing right away and now holding new value with next new value outside

Decoder

N inputs, 2^N outputs but only one output on at a time

Multiplexer (Mux)

Selects one of N inputs to connect to output

SR (set/reset) Latch

Stores one bit of state (Q), S & R control what's being stored

D Latch

Stores one value on the inside (D), when clock goes from 0 to 1, D goes through Q (transparent), otherwise holds value of D (opaque)