What is the advantage of designing the 74193 and 74194 MSI circuits to operate synchronously?

Question

this question is under MSI Sequential Circuits Laboratory.

Please state advantages as much as you can

and thank you soooo much in advance!

Answer 1

Advantages:

1. Output transients ("glitches") will be eliminated if all 4 flip-flops are clocked simultaneously (synchronously), versus being rippled.

2. For small (4-bit) counters like the 74193 synchronous operation is usually faster than ripple operation.  In synchrounous operation the output of the LSB is loaded to the next state to all 4 bits simultaneously, so the delay is one gate (plus setup time).  In a ripple counter, the LSB change must be rippled through 3 setup times to affect the MSB.

3. Timing calculations are easier.  Assuming all flip-flops are identical (which they are), you have 1 setup and 1 hold time to contend with.  So long as the clock speed is less than the total setup time (flip-flop plus logic delays on the inputs), the system will run.

Disadvantage

The input logic to a synchronous counter becomes more complex than a ripple counter.  For larger counters (i.e. 20-bits and more) the logic may become so complex that the counter may not run fast enough.  For larger counters a ripple counter is much simpler than a synchronous counter and may run faster.