ECE 301 Digital Electronics
Introduction & Laboratory Guide
Revised Spring 2016
K. Hintz
The construction of digital circuits has three basic steps. The first is the design stage in which
the underlying logic equations that control the operation of the circuit are determined. These
equations are constrained by the problem statement and much of the activity in class and in the
laboratory will be directed at learning techniques to assist in the determination of the minimum
set of equations needed to satisfy the problem statement.
The next stage is the implementation of the equations using electronic components. At this stage
in the design process you must relate the logical operations to the available functions in your
laboratory kit and draw a schematic of the physical connection of the pins on the selected
integrated circuits (IC). You will use the transistor-transistor logic (TTL) family of IC's in this
course. The TTL family (chip-level design) implements both discrete gates (AND, NAND,
NOR, etc.) and higher level functions (decoders, counters, etc.) into single packages. In general,
the mapping of the logical equations to the available logic gate functions supplied by the IC's in
the laboratory kit are one-to-one, but at times factoring or other manipulations of the equations
may be necessary to arrive at a design that can be implemented with the available components.
The third and most important step, of which the other two are precursors, is the testing and
validation of your design, or in other words, "Does it work"? In this course testing will generally
be accomplished by applying all possible input combinations (test vectors) to the circuit under
test and checking that the output of the circuit agrees with the original design specification.
For a particular design task the amount of effort required for each step may vary from daunting
to obvious. Your laboratory reports will reflect this in that the sections for design,
implementation, and test maybe short, long, or possibly non-existent for a particular laboratory.
You should ask your TA1 if you are not sure whether a section should be included for a particular
laboratory. You should approach the laboratory report as a record, in a format suitable for your
future reference, of the results and discoveries you made in the performance of the experiment
1 The
leaching assistant in the laboratory grades your laboratory performance and reports as well
as your homework. The following procedures and formats apply:
•
You must come to laboratory prepared to perform the experiment. The level of
preparation will depend on the particular laboratory. Some of the early laboratories
require little or no preparation. Later labs require significant preparation if you are to
finish the laboratory in the time allotted.
•
Your laboratory results must be recorded in a bound notebook. You will sign the lab
notebook on the last page of the day's experiment. The TA will briefly review your
notebook entries before you are released from the lab and initial on the last page of your
work. Before the date specified in BB for each individual lab, you will submit an
electronic copy of your lab report for grading via BB (just as you do with homeworks for
the course). This procedure has three goals:
1. To allow you to have access to your lab notebook while preparing for the next
laboratory.
2. To assist you in forming good notebook-keeping habits which maybe required by a
future employer.
3. To make the labs procedures and results readily available for your future reference
and study.
•
Always enter data into the notebook immediately. Neatness is important, but not at the
expense of immediacy.
•
During the laboratory session you will verify that circuits you have designed and built
perform as intended and that your design procedure is correct. Your lab notebook should
include both the design steps used, your implementation of the circuit, and the steps taken
to verify its correct operation. lf you have come prepared you will only need to correct
any mistakes revealed by the testing and enter the test results and any concluding remarks
to complete the laboratory notebook entry for that week.