(a) Expand the circuit of Figure 9-24 to display the contents of two three-stage BCD counters.

(b) Count the number of connections in this circuit, and compare it with the number required if a separate decoder/driver and display were used for each stage of each counter.

Figure 9-24

Transcribed Image Text:

COUNTER SELECT Tens BCD CLK TC counter EN QDQCQBQA ml co S 4 Counter 1 TC TENS 74ALS157 lo MUX (tens) Zo Zo Zo Z₂ Units BCD CLK LED display counter QD QC QB QA BCD-to-7-segment decoder/driver (7447) EN-1 Clock #1 M S E TC UNITS Tens BCD CLK counter QDQCQB QA 1₁ 74ALS157 lo MUX (units) Za Zo Zo Za Counter 2 EN BCD-to-7-segment decoder/driver (7447) LED display TC Units BCD CLK counter EN OD QCQB QA 1 Clock #12 M