Verification #1 · 2026-09-24 · UVM · Medium · about 15 min

The driver that ignores ready

bus_driver sends each byte from its sequencer over a valid/ready bus (bus.sv). A byte transfers on a rising clock edge where valid and ready are both 1, and once valid is 1 it must stay 1, with data unchanged, until that happens.

In a smoke test where the sink is always ready, every byte arrives. As soon as the sink stalls, bytes go missing and the monitor reports handshake errors.

Fix run_phase in driver.sv so every byte arrives exactly once, in order, however often the sink stalls.

Run uses tb.sv: 24 bytes into a sink that's ready 40% of the time. Check the Log for what crossed the bus, and the Waveform for valid, ready and data. Submit runs three hidden tests.

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