Microsoft Word - Digital Logic Design v_4_6a

3.2. Standard Logic and Schematic Layout (Review)

This section describes Small Scale Integration circuits which are commonly used for smaller projects. It
also provides an understanding of the basics of computer design.

Basically, computers regardless of complexity, can be designed using these simple gates as building
blocks. We will start by discussing the most fundamental gates which are AND, OR and NOT.

 AND Function (F=A.B)

 Truth Table

A B F

0 0 0

0 1 0

1 0 0

1 1 1

 Symbols & Operation

• Recommendation is to use the shapes for simple gates; and box (non-shape) for more
  complex logic


• When using in a schematic mark the IC ID (D#) and Pin # on the schematics


• A couple of other representations using switches (Relays, Transistors)

U

A

B

F

A

B

F

&

U

1

F

A B

n.o. n.o.

Vcc = H = 1

n.o.

n.o.

n.c. n.c.

GND = L = 0

F 0=L=V L

1=H=V H^

IEEE: Shape Distinctive Graphics

Symbol

IEC: Non-Shape Distinctive

Graphics Symbol

Pass Logic Switching Circuit

0: Button is Not pressed

1: Button is pressed

Regenerative Logic Switching

Circuit

A

B

1

2

3

1

2

3