This course was an introduction to the basic logic gates, AND, OR and NOT using actual gate ICs. The use of the logic tutor,
shown below, and the prototyping board was introduced here. The operation of the basic gates was investigated practically,
and the way that devices are described in data sheets was also introduced here. This skill is necessary when converting a
logic diagram to a list of connections needed to produce a working circuit using logic gate ICs.
The next stage was to create logic functions combining these basic gates such as NOT AND (NAND) and NOT OR (NOR) and check
operation against a Truth Table. Finally, a task to allow these skills to be used in a practical example was developed using
a 7 segment LED display. The four combinations of logic levels from the two switches were expressed in logical terms. These
were then simplified using boolean algebra and implemented in a circuit built from basic gates. The outputs of this circuit
were connected to segments "a" to "g" on the display. Testing for correct operation was achieved by comparing the binary value
of the two switches to the number on the display for all possible combinations. The image below is of the circuit driving
the 7 segment LED display. [The circuit in the bottom right hand corner is a driver needed to convert the logic ciruit output
to drive a Common Anode display]
The idea of having three types of pages for the material was tested here. The first was theory to support the work, the
second was design and build information and the third testing. The work was split into stages with links at the end of
each stage to move to a separate type of page. This gave the student some control over the work allowing for different
styles of working. Some students may prefer to go through all the theory first, then go back and do the practical work
whereas others may prefer the method of completing each stage before moving on.
