RTL Design #36 · 2026-10-29 · Width conversion · Easy · about 10 min

A width converter that skips a beat under backpressure

narrow turns a 16-bit word into two 8-bit beats, with valid/ready on both sides. A beat moves when valid and ready are both 1 at a rising edge.

• The converter takes one word at a time. in_ready is 1 whenever it holds no word, and 0 while it is sending one.
• It sends the low byte first, then the high byte. out_last is 1 on the high byte only.
• While out_valid is 1 and out_ready is 0, out_valid, out_data and out_last hold.
• After the high byte moves, the converter is empty and in_ready returns to 1.
• After reset it is empty.

With the consumer always ready the design works. When the consumer stalls, bytes go missing. Fix narrow.sv.

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