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+# Datasheets in use
+
+Only the parts this design actually depends on. The wider WCH collection —
+including the CH32X035 and CH32V203 docs used to rule out crystal-less USB —
+lives in `~/Documents/Projects/WCH CH ICs/`.
+
+| File | Part | Why it's here |
+|---|---|---|
+| `CH32L103DS0.PDF` | CH32L103C8T6 | The MCU. Pinout, 64 K flash / 20 K SRAM, HSI accuracy table (§3.3.6), USBFS with 8 device endpoints (§1.4.20). |
+| `CH32L103RM.PDF` | CH32L103C8T6 | Reference manual. USB clock path (§3.3.5.6), `RB_UC_DEV_PU_EN` internal 1.5 kΩ D+ pull-up, HSICAL/HSITRIM. |
+| `CH334DS1.PDF` | CH334R | The hub. Variant feature table (which packages expose `PSELF` and port power switching), crystal-free caveats (§6.2), and the CH213 reference design for VBUS protection. |
+
+## Missing
+
+- **STM32F103C8T6 datasheet** — the pin-compatible escape-hatch MCU. ST's site
+  refused automated download; grab it from st.com or the LCSC CDN and drop it
+  here. Needed to do the pin-number overlay flagged in the top-level README.