UVM · Topic
UVM Sequences — body(), start() and the Driver Handshake
Writing sequences, starting them on a sequencer, and the start_item/finish_item handshake that paces stimulus against the driver.
A sequence generates transactions; a driver turns them into pin activity. The handshake between them is what makes stimulus flow-controlled rather than free-running: `start_item` blocks until the driver is ready, and `finish_item` blocks until the driver has taken the item. Sequences that ignore this — by generating into a queue, or by racing ahead — produce testbenches whose behaviour depends on simulation speed, and whose bugs disappear when tracing is enabled.