Question

1.IC 74161 is a synchronous 4-bit counter designed by Texas Instruments (TI). Find the data sheet for this IC on Google and

answer the following questions:

a)Use two 74161 ICs to design an 8-bit counter. Hint: work with the IC input and output pins.

Consider the count sequence: 0-> 1-> 2-> 3-> 4-> 5-> 0 ....

b) Use a 74161 IC and the “Clear” input pin to implement this count sequence.

c) Use a 74161 IC and the “Load” input pin to implement this

count sequence.

d) How would the results in (b) and (c) be different if we use synchronous Clear/Load signals? How about if we use asynchronous Clear/Lead signals?

Answer 1

1(a)

(b)

(c)

(d) In (b) CLEAR is asynchronous and hence we use 0110 (6) comparison with output to clear the counter.

In (c), LOAD is synchronous and hence we use 0101 (5) for comparison with output and load 0000 in next clock of 0101.

In case of synchronous CLEAR we will use 0101 for comparison instead of 0110 and similarly if LOAD is asynchronous then we will use 0110 instead of 0101.