Mermaid — NPU block diagram

Mermaid renders on the client, so the diagram below picks up Furo’s dark/light theme automatically via the neutral Mermaid palette configured in conf_common.py.

        flowchart LR
    HOST[Host CPU] -- AXI-Lite --> CTRL[NPU Controller]
    CTRL --> GEMM[GEMM Core<br/>32×32 · 2-MAC DSP]
    CTRL --> GEMV[GEMV Core<br/>4 × 32-MAC]
    CTRL --> SFU[SFU / CVO]
    CTRL --> DMA[DMA]
    GEMM <-- HP0/HP1 --> DDR[(DDR4)]
    GEMV <-- HP2/HP3 --> DDR
    DMA  <-- ACP    --> DDR
    GEMV -. direct FIFO .-> SFU
    GEMM --> L2[(Shared L2<br/>URAM 1.75 MB)]
    GEMV --> L2
    SFU  --> L2
    

The flowchart should compose without a round trip to a rendering service — if the box renders blank, check the browser console for a Mermaid parse error (most often caused by reserved keywords inside labels).

When to reach for Mermaid

• High-level flow, state-machine, or sequence diagrams that benefit from being diffable text.

• Quick sketches where fidelity is less important than authoring speed.

For performance-critical datapath diagrams with exact proportions, prefer inline SVG (SVG — themed 4×4 PE array) — Mermaid’s auto-layout is convenient but coarse.