INEL 4215

Lecture 4

1.5 The Computer System Logic Designer’s View

The Computer System Logic Designer – Responsible for designing the machine at the logic gate level. (Most of the time is the same person as the computer architect).

1.5.1 Implementation Domain

Implementation Domain- The collection of hardware devices with which the logic designer works.

Example:

v Transistor Transistor Logic (TTL)

v Emitter Coupled Logic (ECL)

v Programmable Logic Arrays (PLA)

v Etc.

Two levels of abstraction

Logic level – logic functions

Physical level – fan-in, fan-out, propagation delay, etc.

See figure 1.7 (textbook)

1.5.2 Importance of Implementation Domain

When translating from abstract level to concrete domain

Issues:

Space

No. units available

Organization within chip

Modularity

1.5.3 Distinction between classical logic design and computer logic design

Cannot design as a finite state machine!!

# of states

Abstraction – independence of subsystems

CPU ←→Memory

Natural separation between

Data path

Control path

Logic designer sees NAND gates, NOR gates, D Flip Flops

Computer designer sees – Muxes, decoders, registers, black boxes.