1,000+ ASIC Interview Questions: SystemVerilog, UVM & RTL

DescriptionQ335

Q335DesignArchASIC interview problem

Schedule bank commands with accepted-slot cooldown

TechniquesSchedulerCooldownDeterministic arbitration

DifficultyMedium

TopicRTL Design

LanguageSystemVerilog

Requirements5 checkpoints

Problem

Buffer a frame of commands for four banks, then reorder across banks so repeated commands to one bank have at least C intervening accepted slots. Emit accepted idle tokens only when no pending bank is eligible.

Example input and output

Use this case to check your interpretation

Input

C=1; framed commands in arrival order: bank0=A, bank0=B, bank1=C

Output

accepted slots: bank0 A, bank1 C, bank0 B

Explanation

Bank 0 initially has the largest queue; after A, one accepted command from bank 1 supplies the required intervening cooldown slot before B.

Requirements (5)

Buffer 1 through 16 commands and capture C in the range 0 through 3 with the first command.
Preserve arrival order within each bank while allowing reordering across banks.
Choose the eligible bank with the largest pending count and break ties by lower bank ID.
Advance cooldown, FIFO heads, and pending counts only when slot_valid and slot_ready are both high.
Count accepted idle tokens as intervening slots and hold the selected token stable during backpressure.