1) Draw the state diagram for the state machine described by Table 7.5 in the text. Note, the table shows the transition to the next state S* from the current state S for the next set which is one of the five possible states: INIT, A0, A1, OK0 and OK1 for the two inputs A and B.
Table 7-5 State and output table
present
state
S 00 01
INIT A0 A0
A0 OK0 OK0
A1 A0 A0
OK0 OK0 OK0
OK1 A0 OK0
AB
11 10 Z
A1 A1 0 A1 A1 0 OK1 OK1 0 OK1 A1 1 OK1 OK1 1 next state S*
2) Draw the state diagram for a binary counter that counts from 0 to 7 and then returns to 0. The counter will increment each time the input is a 1. It will stay in the current state while the input is 0. When the counter is at a count of 7, the output will be a 1 as the counter transitions back to state 0. For all other state transitions, the output will be a zero. Hint, you will want to design this using a state diagram for a Mealy machine where the output is specified on the arch showing the transition to the next state for a given input since the output is a 1 only during the transition from state 7 to state 0. Remember, the arch has the notation input/output showing the input that causes the transition described by the arch from state i to state j and the output value corresponding to that arch.
3) Design a clocked sequential circuit to detect the serial input pattern 1110. The input sequence is from left to right, i.e. the 1 on the left is the first input in the sequence and the 0 is the last input in the sequence. The circuit will have two outputs. The first output will be a 1 after the string 11 is seen. The second output will be 1 only after the entire string has been seen. So, in your design you will have two output variables and need a kmap for each output as well as the two state variables. Use D-Flip flops. Show all of your work, the state diagram, the state table, the transition table, the excitation table, the k-maps, the equations and the circuit diagram. Hint, again we will want to draw a Mealy state diagram. See the sequence detector designed in lecture 7 as a similar example.