This is your second design assignment. This assignment requires you to design a complex state machine.

You are designing a digital alarm clock. There are various designs you can attempt. More complex designs are worth more marks than simpler designs.

The basic clock displays the time in 12 hour mode. From 01:00:00 to 12:59:59. A more advanced clock allows the user to select whether the time is displayed in 12 or 24 hour mode. This is selected by use of a switch, which is high for 12 hour mode, and low for 24 hour mode. Changing between 12 and 24 hour mode does not require the time subsequently displayed to be valid, however, on the next hour change the time must become a valid time. If the hour is adjusted whilst invalid it must become valid on the next change. Valid 24 hour times are 00:00:00 to 23:59:59.

The full clock takes the advanced clock and allows you to set the time, and easily adjust for daylight savings.

The alarm clock extends the full clock with an alarm. The alarm can be set for any valid time. When the alarm is triggered the alarm signals for one minute and then resets. There is a silence button for the alarm which will silence the alarm, and an on-off button for the alarm which will prohibit the alarm from triggering.

The supreme clock includes a calendar unit. It will allow the date to be set, and will count the days through the year. At 02:00 on the 1st of October the hour will also increment, leading to 01:59:59->02:00:00->03:00:01, and at 03:00 on the 1st of April the hour will be decremented, leading to the sequence on the display of 02:59:59->03:00:00->02:00:01. The supreme clock may, or may not include leap years of some variant. Finally, the supreme clock does not need to handle changes between calendars, but can assume the Gregorian calendar in perpetuity.

Requirements:

You are to design a complex state machine. This state machine will encompass multiple simpler state machines. At a minimum you will need six simple state machines, one each for: seconds units, seconds tens, minutes units, minutes tens, hours units, hours tens. You are provided with a one second clock pulse that will be triggering a state transition for your system.

For each simple state machine you need to provide the state transition table, as well as the equations for that state machine. Provide the interconnections between the simple state machines that cause this to be a complex state machine.

The minimum inputs your system is provided with are:

The general outputs your system should provide are:

For each output provide its definition in a state transition table as well as its equation.