HD74HC194 Datasheet, PDF (2/8 Pages) Hitachi Semiconductor – 4-bit Bidirectional Universal Shift Register

HD74HC194
Function Table
Inputs
Operating
Mode
Serial
Parallel
Outputs
Mode
Clear
Clear S₁ S₀ Clock Shift Left Shift Right A B C D Q_A Q_B Q_C Q_D
L XXX
X
X
XX XXL L L L
Parallel load H H H
X
X
ab cda b c d
Shift right H L H
X
H
XX XXH
Q_An Q_Bn Q_Cn
H LH
X
L
XX XXL
Q_An Q_Bn Q_Cn
Shift left
H HL
H
X
X X X X Q_Bn Q_Cn Q_Dn H
H HL
L
X
X X X X Q_Bn Q_Cn Q_Dn L
Hold
H LLX
X
X
X X X X Q_A0 Q_B0 Q_C0 Q_D0
H XXL
X
X
X X X X Q_A0 Q_B0 Q_C0 Q_D0
H
XX H
X
X
H : high level (Steady state)
L : low level (Steady state)
X : don’t care
X X X X Q_A0 Q_B0 Q_C0 Q_D0
:
transition from low to high level.
a, b, c, d : the level of steady-state input at inputs A, B, C or D respectively.
Q_A0, Q_B0, Q_C0, Q_D0 : the level of Q_A, Q_B, Q_C or Q_D respectively, before the indicated steady-state input
conditions were established.
Q_An, Q_Bn, Q_Cn, Q_Dn :
the clock.
the level of Q_A, Q_B, Q_C or Q_D respectively before the most recent transition of
2