Safe boundaries between clock domains
CDC and reset interviews reveal whether a candidate understands the limits of synchronous reasoning. A two-flop synchronizer does not eliminate metastability, a pulse may disappear when clocks differ, and a multi-bit bus cannot be made coherent by synchronizing every bit independently.
Use these questions to match each crossing to an appropriate contract: level synchronization, pulse or toggle transfer, request-acknowledge handshake, Gray-coded counter, or asynchronous FIFO. Then connect the structure to verification and implementation.
Topic breakdown
Choose synchronizers, toggles, or handshakes from the signal semantics and the clocks' event-rate relationship.
Move multi-bit state safely with stable-data protocols, Gray counters, and correctly sized asynchronous FIFOs.
Coordinate assertion and release, define timing exceptions narrowly, and verify domain-specific recovery behavior.
Curated practice links
Permanent bank numbers and direct links make it easy to continue in the live question bank.
Explain the key CDC and Metastability decisions, assumptions, and checks.
Clock Domain Crossing · MediumExplain the key Reset and Async assert decisions, assumptions, and checks.
Reset Design · EasyExplain the key Gray code and Counter decisions, assumptions, and checks.
Clock Domain Crossing · MediumExplain the key Async FIFO and Gray code decisions, assumptions, and checks.
Clock Domain Crossing · HardExplain the key Reset sequencing and PLL lock decisions, assumptions, and checks.
Clock and Reset · HardExplain the key CDC and Synchronizer decisions, assumptions, and checks.
Clock Domain Crossing · EasyExplain the key CDC and Asynchronous FIFO decisions, assumptions, and checks.
CDC Verification · MediumExplain the key Reset and Timing decisions, assumptions, and checks.
RTL Design · EasyExplain the key Reset and Registers decisions, assumptions, and checks.
RTL Design · EasyExplain the key CDC and Coherency decisions, assumptions, and checks.
Clock Domain Crossing · MediumExplain the key CDC and Asynchronous FIFO decisions, assumptions, and checks.
Clock Domain Crossing · MediumExplain the key CDC and Gray code decisions, assumptions, and checks.
Clock Domain Crossing · MediumExplain the key STA and CDC decisions, assumptions, and checks.
Static Timing Analysis · MediumExplain the key Reset and Clock gating decisions, assumptions, and checks.
Low-Power Design · MediumExplain the key CDC and Level shifting decisions, assumptions, and checks.
Low-Power Design · HardExplain the key CDC and Asynchronous FIFO decisions, assumptions, and checks.
Clock Domain Crossing · HardExplain the key CDC and Asynchronous FIFO decisions, assumptions, and checks.
Clock Domain Crossing · HardExplain the key Synchronizer and Handshake decisions, assumptions, and checks.
Clock Domain Crossing · MediumExplain the key Reset and CDC decisions, assumptions, and checks.
Reset Design · MediumExplain the key CDC and Clocking decisions, assumptions, and checks.
Clock and Reset Domains · EasyExplain the key CDC and Clocking decisions, assumptions, and checks.
Clock and Reset Domains · MediumExplain the key CDC and Clocking decisions, assumptions, and checks.
Clock and Reset Domains · MediumExplain the key CDC and Clocking decisions, assumptions, and checks.
Clock and Reset Domains · MediumExplain the key CDC and Clocking decisions, assumptions, and checks.
Design Verification · MediumExplain the key CDC and FIFO decisions, assumptions, and checks.
Clock and Reset Domains · MediumExplain the key CDC decisions, assumptions, and checks.
Clock and Reset Domains · MediumExplain the key SVA and Reset decisions, assumptions, and checks.
Clock and Reset Domains · MediumExplain the key SVA and Reset decisions, assumptions, and checks.
Clock and Reset Domains · MediumExplain the key CDC and Clocking decisions, assumptions, and checks.
Clock and Reset Domains · MediumExplain the key SVA and CDC decisions, assumptions, and checks.
Clock and Reset Domains · Hard