A simplified, HF-only software-defined radio (SDR) receiver based on the RX-888 — a proof-of-concept on a larger 6-layer board with improved thermal and RF layout.
The KiCad project lives at the repository root (TAPRX-888.kicad_pro /
.kicad_sch / .kicad_pcb). KiCad 10.0 is the project baseline.
- HF-only — no VHF up/down converter
- Larger PCB, 6-layer
- No bottom-side components
- 0603 passive components
- Improved thermal layout
- Improved RF input filter(s) (bypassable)
- External reference clock input, auto-switching
- Attenuated filter-bypass injector port (used for timesync)
- SPI boot prom. configurable as USB boot, SPI boot, SPI boot with USB fallback.
Please see the schematic and layout documents for details.
| Function | Part |
|---|---|
| ADC | LTC2208 (16-bit) |
| Clock generator | Si5351 |
| USB3 controller | EZ-USB FX3 (CYUSB301x) |
| SPI boot flash | MX25L3233F |
dev— integration branch and the repository default; day-to-day work lands here.main— tagged, released board revisions.design— where the schematic and PCB are edited (one person at a time, because KiCad layout files can't be merged).
See CONTRIBUTING.md for the full workflow. In short:
- Design edits (schematic / PCB / libraries) happen one person at a time on the
designbranch. - Everything else (CI, design rules, BOM tooling, docs) is a short
dev-*branch opened as a pull request intodev. dev→main(tagged) is a release, cut by consensus.- ERC and DRC run in CI as the shared source of truth.
Fabrication and design packages are built by CI and published as versioned
GitHub Releases — gerbers, drill, LCSC BOM, pick-and-place, interactive BOM,
and the schematic + assembly PDFs, each stamped with its version and commit hash.
Grab the latest from the
Releases page (pre-releases are
v0.x; production spins are v1.0, v2.0, …). See
docs/RELEASE_STRATEGY.md for how versioning works.
- CONTRIBUTING.md — how we collaborate (the two-lane
design/ infra flow, the design baton) - docs/RELEASE_STRATEGY.md — versioning, CI, and how releases are cut
- docs/AI_REVIEW.md — using AI review responsibly; read this before pointing an AI tool at the design
- docs/EMERGENCY_ROLLBACK.md — the parachute: how to turn the CI/branch machinery off if it's ever too much
Device datasheets (LTC2208, Si5351, EZ-USB FX3, MX25L3233F) and RX888 reference material are on the project wiki → Reference Documents.