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Q046DVASIC interview problem

FIFO Count Changes on Simultaneous Push and Pop

TechniquesDVWaveform DebuggingFIFO
DifficultyEasy
TopicWaveform Debugging
LanguageSystemVerilog
Format4 choices
01

Problem

The FIFO is neither full nor empty. push and pop are accepted whenever asserted. count is the occupancy after each edge. Rule to apply: One accepted push adds one entry, one accepted pop removes one entry, and simultaneous accepted push and pop leave count unchanged. What causes the count mismatch at C3?

Waveform for FIFO Count Changes on Simultaneous Push and Pop. Signals: push, pop, count. Numbered markers identify sampled columns.
Read the sampled columns from left to right, then test each choice against the stated timing rule.
02

Answer choices (4)