The ASM chart can be drawn by defining four states q1, q2, q3 and q4 as shown in Figure. Each state corresponds to a time period of one clock pulse. The output Z in any state is dependent conditionally on the inputs X1 and X2.
ASM block for first clock cycle :
In the state q1 corresponding to the first clock pulse, all the waveforms are high. Hence the output of the waveform generator (Z) should be 1 irrespective of the value of X1 and X2.The ASM block for the first clock cycle is shown in Figure.
ASM block for second clock cycle : In the second clock pulse state q2 will come in picture. In this state the output Z =1 For all the other combination of inputs except for X1 X2 = 11. The chart upto this state is shown in Figure.
ASM chart for third clock pulse : In the third clock pulse the corresponding state is q3. The generator output Z =1 if X2 = 1. The chart upto this state is shown in Figure.
State q4 is corresponds to the fourth clock pulse. Output Z of the waveform generator is â€˜0â€™ irrespective of the inputs X1 and X2. In the next clock cycle the operation starts repeating itself. The complete ASM chart is shown in Figure below.