š Key Concepts
ā¢ Truth tables for flip-flops vs. shift registers vs. simple converters
ā¢ How D-type flip-flops behave with respect to clock, data (D), and output (Q, QĢ
) including 3āstate outputs
ā¢ Difference between 2-state vs. 3-state logic outputs and inverting vs. non-inverting behavior
š Think About
ā¢ Look at how many inputs and outputs are shown in the truth table and what they are labeled (e.g., D, CLK, EN, Q, QĢ
, OE, etc.). What kind of device normally uses that exact combination?
ā¢ Check what happens to the output(s) when the clock changes state. Does the device store a single bit, shift bits, or simply pass/convert a signal?
ā¢ Does the truth table show a highāimpedance (HiāZ) or ādisabledā state for the output? If so, what does that tell you about 2āstate vs. 3āstate and which options that rules out?
ā
Before You Answer
ā¢ Confirm whether the truth table shows Q and QĢ
(inverted output) or only a single output line.
ā¢ Verify if there is any indication of 3āstate (HiāZ) output, which would distinguish 3āstate from 2āstate devices.
ā¢ Check whether the truth table shows data being shifted through multiple stages (characteristic of shift registers) or just stored/transferred on a clock edge (characteristic of flipāflops/converters).