ELEC 242 — Continuous-Time Signals and Systems

Introduction:
In this design assignment the aim is to build a digital alarm clock which is able count
automatically the hour, minutes and seconds and for an advanced version it will give the user
the option to set the timer, count the year, triggering the alarm when the specified time is
reached and implement the daylight saving s mode (which is hour count decrement when the
daylight savings mode is off). In case of the supreme clock there will be an option to set the
date and with every 24 hours passed the day count will be increased. Also, for a more
advanced design the leap years can be included.
Design:
The total clock circuit is designed using Logisim software where main circuit composed of
three circuits the upper segment circuit, a decoder circuit and a lower segment circuit. For
turning ON the clock the ticks of Logisim clock is enabled. The clock design gives the user to
set the hours, minute and second individually and the time of day is displayed through AM
and PM. The designed decoders are used in the Upper segment subcircuit along with various
flip flops and basic gates with a clock. The lower segment subcircuit contains only some
splitters, outputs and basic gates. Finally, the three subcircuits are used to make the final
clock circuit as given below.
Lower segment circuit:

Decoder circuit:
Upper segment circuit: