# External DB

> External reference-database expert. Before authoring new RTL — or answering from assumed knowledge — consult the configured external DB for proven, authoritative references instead of reinventing. The DB is typically a prior-project / vendor RTL corpus (e.g. Andes peripherals: UART, SPI, I2C, GPIO, DMA, AHB bus matrix, bridges, timers), but it is NOT limited to RTL: it can hold spec excerpts, reference designs, datasheets, or any prior-art knowledge wired in by the deployment. Trigger on: external db, reference db, reference design, prior art, reuse, existing rtl, previous project, knowledge base, and common peripheral/bus families (uart, spi, i2c, gpio, dma, apb, ahb, bus matrix, bridge, timer, watchdog, rtc, fifo).

- Skill: `together2329/external-db` (Agent Skill)
- Install (CLI): `npx skillmds@latest add together2329/external-db`
- Raw SKILL.md: https://api.skillmd.com/api/skills/together2329/external-db/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Research & Search
- Author: together2329 (https://skillmd.com/u/together2329)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/together2329/external-db

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# ⚠️ MANDATORY: Check the external DB before reinventing

**Before generating/hand-writing RTL for a peripheral or bus block — or stating a
"reference" design or convention — FIRST query the external reference database for an
existing, proven source. Reuse interface conventions, module decomposition, register
layouts, and cited facts rather than inventing them.**

The external DB is, by design, *external* and **data-source-agnostic** — this skill
does not assume any structure, and the DB is optional. If no wiki, builder, or query
hook is configured, say the external DB is unavailable and continue from the active
SSOT/spec. The deployment wires the source via any one of (newer `ATLAS_EXTERNAL_DB_*`
names are preferred; legacy `ATLAS_RTL_DB_*` still work):

- `…_WIKI` — a wiki directory (markdown + `_graph.json`).
- `…_BUILDER` — an external converter that builds `_graph.json` from a foreign corpus.
- `…_QUERY` — an external executable that owns the *entire* query (its own structure /
  search / transport: files, DB, HTTP, vector store…).

You never need to know which is configured — always go through `external_db_query`
for external DB lookup. `wiki_query(ip="external-db", ...)` is the underlying
compatible path when a caller needs the generic wiki tool.
This activation model is the same style as protocol/reference skills such as
`pcie-expert`, `nvme-expert`, or `ucie-expert`: the skill can trigger whenever the work
needs prior art, but useful answers depend on the configured data source.

## How to query

```
external_db_query(topic="<block / interface / topic>", depth=3)
```
Equivalent generic form: `wiki_query(ip="external-db", topic="<topic>", depth=3)`.
(`ip="rtl-db"` / `"andes"` are accepted aliases on `wiki_query` for the same source.)

Examples:
```
external_db_query(topic="uart apb dma fifo", depth=3)
external_db_query(topic="ahb bus matrix interconnect", depth=2)
external_db_query(topic="spi flash bridge", depth=3)
external_db_query(topic="module port parameter fsm datapath register memory clock reset docs datasheet", depth=3)
```

`depth`: 1 = id+title, 2 = +status/meta, 3 = +summary. Start broad (a family keyword
or `topic=""`), then drill into the specific id the first query surfaces.

## Workflow

1. **Identify the block/interface/topic** from the SSOT or the user's request.
2. **Query the external DB** with the relevant family + interface keywords. For RTL
   reuse/reference work, include AST-level terms when useful: `module`, `port`,
   `parameter`, `fsm`, `datapath`, `register`, `memory`, `clock`, `reset`, `docs`,
   `datasheet`.
3. **If a match is found**, cite it (id + path) and reuse its conventions:
   bus signal set + naming (APB `psel/penable/paddr/…`, AHB `haddr/htrans/…`),
   module decomposition, register map, reset/clock conventions.
4. **If nothing matches**, say so explicitly and proceed cleanly — never fabricate a citation.

## Rules

- Never claim something exists in the external DB without a `wiki_query` result backing it.
- Reuse *conventions and structure*; the active IP's SSOT remains authoritative on conflict.
- Complements the protocol spec experts ([[verilog-expert]], `pcie-expert`, …): use those
  for spec semantics, use this for "has someone already built / documented this?".