Parallel-to-Serial, Serial-to-Parallel

Conversions

Left or Right Shifts

Parallel Synchronous Loading

Direct Overriding Clear

Temporary Data-Latching Capability

Package Options Include Plastic

Small-Outline Packages (D), Ceramic Chip

Carriers (FK), and Standard Plastic (N) and

Ceramic (J) 300-mil DIPs

description

These 4-bit bidirectional universal shift registers

feature parallel outputs, right-shift and left-shift

serial (SR SER, SL SER) inputs, operatingmode-

control (S0, S1) inputs, and a direct

overriding clear (CLR) line. The registers have

four distinct modes of operation:

• Inhibit clock (temporary data latch/do nothing)

• Shift right (in the direction QA toward QD)

• Shift left (in the direction QD toward QA)

• Parallel (broadside) load

Parallel synchronous loading is accomplished by

applying the four bits of data and taking both S0

and S1 high. The data is loaded into the

associated flip-flops and appears at the outputs

after the positive transition of the clock (CLK)

input. During loading, serial data flow is inhibited.

Shift right is accomplished synchronously with the rising edge of the clock pulse when S0 is high and S1 is low.

Serial data for this mode is entered at the shift-right data input. When S0 is low and S1 is high, data shifts left

synchronously and new data is entered at the shift-left serial inputs. Clocking of the flip-flop is inhibited when

both mode-control inputs are low.

The SN54AS194 is characterized for operation over the full military temperature range of −55°C to 125°C. The

SN74AS194 is characterized for operation from 0°C to 70°C.