6.2 DIGITAL SYSTEM COMPONENTS 297A 0 A 1A 0
A 1
A 210
10
11
11A 20
1
0
100
00
01
010
1
0
1Q 7Q 0
Q 1
Q 2
Q 3
Q 4
Q 5
Q 6
Q 7Q 600
00
01
10Q 50
1
0
000
00
00
000
0
0
0Q 4 Q 310
00
00
00Q 20
0
0
000
00
00
010
0
1
0Q 1 Q 000
00
00
0001
10
00
00A 2 A 1 A 0
Q 0Q 1Q 2Q 3Q 4Q 5Q 6Q 7(b)(c)(a)Figure 6.2.13-to-8 decoder.(a)Block diagram.(b)Truth table.(c)Logic diagram.
next one on the right. The waveforms also reveal that the data are read into the registerserially
and appear at the output in serial form. The shift register is then known as aserial-in serial-out
(SISO) register.
PISO (parallel-in serial-out), SIPO (serial-in parallel-out), and PIPO (parallel-in parallel-
out) registers are also often used to read in the input data and read out the output data in a