Lab 8 Synchronous Counter Design

Lab 8 Synchronous Counter 1lab 8 Synchronous Counter Design

This is a simulation only lab: Design a synchronous counter that will count the following sequence: 0, 1, 4, 5, 8, 9, 12, 13, and then recycle. Implement your circuit using negative edge-triggered J-K Flip Flops (74LS76). The clock will be a 5V, 1Hz pulse signal. You will submit your design process in a neat and orderly (digital) manner.

Construct and simulate the entire circuit in Multisim. Use the 4-channel oscilloscope to verify the count sequence. Beneath the oscilloscope, use the waveforms to list the count sequence. This lab may be completed at your convenience. You may work on this lab in NE 2380 during your scheduled lab time or in any of the computer labs on the engineering campus at your convenience.

Paper For Above instruction

Designing a synchronous counter to follow a non-standard sequence involves a comprehensive understanding of flip-flop operation, digital logic design, and simulation techniques. The objective of this lab is to create a circuit that accurately counts through the sequence 0, 1, 4, 5, 8, 9, 12, 13, and then repeats, utilizing negative edge-triggered J-K flip-flops (74LS76). This process showcases the application of sequential logic design principles in digital electronics, emphasizing timing, state transition, and circuit verification through simulation.

The initial step involves analyzing the desired count sequence to determine the necessary states and transitions. Converting each decimal number into binary provides a basis for designing the circuit. The sequence in binary form is as follows:

• 0 = 0000
• 1 = 0001
• 4 = 0100
• 5 = 0101
• 8 = 1000
• 9 = 1001
• 12 = 1100
• 13 = 1101

Next, a state transition diagram is developed to visualize the movement from one state to the next. Since the sequence is non-linear, the counter transitions require careful logic to ensure the sequence is followed correctly. Based on this, the excitation table for a J-K flip-flop is constructed, which helps determine the necessary inputs (J and K) for each flip-flop to achieve the desired state transitions. The previous states and next states guide the logic design, ensuring that the flip-flops toggle appropriately to produce the sequence.

Following the logic derivation, combinational logic circuits are designed to generate the J and K inputs based on the current state outputs. This involves simplifying boolean expressions using Karnaugh maps or Boolean algebra to minimize the logic gates. The logic design also includes considering the asynchronous set/reset features if needed, but in this case, primarily focusing on the clocked toggling with the negative edge trigger.

Implementation in Multisim involves creating a schematic incorporating four J-K flip-flops, each representing one bit of the counter. The flip-flops are connected so that their outputs form the current state, which feeds into the combinational logic for determining the next state. The clock signal is a 5V, 1Hz pulse generated within Multisim, applied to all flip-flops simultaneously. The negative edge trigger ensures proper synchronization with the clock's falling edge.

Verification of the circuit involves using a 4-channel oscilloscope in Multisim to observe the waveforms of each flip-flop output. By analyzing these waveforms, the sequence of states can be confirmed matches the intended count of 0, 1, 4, 5, 8, 9, 12, and 13. Documenting these waveforms provides a visual validation that the counter functions as designed.

The experiment underscores practical digital system design by integrating theoretical principles with simulation tools. It highlights the importance of logical minimization, timing analysis, and verification through signal observation. Issues such as glitch prevention and ensuring stable state transitions are addressed within the design process, exemplifying fundamental concepts of synchronous digital circuits.

Conclusion

The successful completion of this laboratory task demonstrates the effective design and simulation of a non-linear synchronous counter using negative edge-triggered J-K flip-flops. The precise sequence counting proved feasible through systematic state analysis, Boolean simplification, and careful circuit implementation. The use of Multisim provided a valuable platform for verifying the circuit's operation and ensuring that the counter displays the correct sequence on the oscilloscope. This project reinforces critical digital design skills, including state machine analysis, logic simplification, and simulation-based validation, which are essential in advanced digital system development.

References

• R. L. Hambley, Introduction to Digital Systems, 7th ed., Pearson, 2018.
• M. M. Mano and C. R. Kime, Logic and Computer Design Fundamentals, 3rd ed., Pearson, 2007.
• F. J. Hill, Digital Fundamentals and Applications, 2nd ed., McGraw-Hill, 2000.
• N. Weste and D. Harris, CMOS VLSI Design: A Circuits and Systems Perspective, 4th ed., Pearson, 2010.
• Analog Devices Inc., J-K Flip-Flop Datasheet (74LS76), 1978.
• Multisim User Guide, National Instruments, 2017.
• R. T. Beale, Digital Logic and Computer Design, Schaum's Outline Series, McGraw-Hill Education, 2012.
• S. Brown and Z. Vranesic, Fundamentals of Digital Logic with VHDL Design, McGraw-Hill, 2009.
• K. Bidgoli, Electronic Devices and Circuits, Cengage Learning, 2014.
• Y. Chen, Simulation and Design of Sequential Circuits in Multisim, IEEE Transactions on Education, 2019.