Introduction / Context:
Shift registers are versatile building blocks for data movement and temporary storage in digital systems. Two common types are PISO (parallel-in/serial-out) and SIPO (serial-in/parallel-out). This question probes whether a SIPO by itself “moves data from one parallel bus to another” via a single wire, which is a subtle but important point for system designers.
Given Data / Assumptions:
- SIPO has one serial input, a shift clock, and multiple parallel outputs.
- Transferring data between parallel buses typically implies parallel capture at the source and parallel presentation at the destination.
- No additional stages (like a PISO at the source) are explicitly included in the statement.
Concept / Approach:
A SIPO converts a serial stream into a parallel word. To move a word from a parallel source bus onto a single serial line first, you need a PISO at the source to serialize it. Then a SIPO at the destination deserializes it back to parallel. A SIPO alone does not perform parallel-to-parallel transfer; it only performs serial-to-parallel conversion.
Step-by-Step Solution:
Identify SIPO function: serial input → parallel outputs.Identify requirement for bus-to-bus: parallel source → serialize → send → deserialize → parallel destination.Notice missing PISO stage in the claim.Conclude the stated claim about SIPO alone is incorrect.
Verification / Alternative check:
Textbook signal-flow examples always pair PISO (source) with SIPO (destination) when bridging two parallel buses over a single line.
Why Other Options Are Wrong:
Correct: Overstates what a SIPO can do unaided.Applies only with an added PISO stage: This is a condition, not the requested true/false evaluation of the original claim.Valid for tri-state buses only: Bus electrical style does not change the logical requirement.
Common Pitfalls:
Conflating the paired PISO+SIPO link with SIPO alone.Assuming “parallel bus” implies any register with multiple outputs.
Final Answer:
Incorrect
Discussion & Comments