Figure 9-84 shows two more devices that are to be added to the data bus of Figure 9-47. One is a set of buffered switches that can be used to enter data manually into any of the bus registers. The other device is an output register that is used to latch any data that are on the bus during a data transfer operation and display them on a set of LEDs.

(a) Assume that all registers contain 0000. Outline the sequence of operations needed to load the registers with the following data from the switches: [A] = 1011, [B] = 0001, [C] = 1110.

(b) What will the state of the LEDs be at the end of this sequence?

Figure 9-84

Figure 9-47

Transcribed Image Text:

+5 V 1 ΚΩ SW3 SW2 SW1 SWO 74HC125 Esw CLOCK- (from Figure 9-47) Data bus from Figure 9-47 DB 3 DB2 DB, DBo 74HC174 D3 D₂ D₁ Do CLK Q3 Q₂ Q₁ Qo 220 Ω 7406 2 e 2 1 +5 V ww