William RickertandClaude Opus 5
49ad7e97cf
Parsed the pin-definition tables out of both datasheets - Table 2-1-1 (CH32L103, C8T6 column) and Table 2 (STM32F103, LQFP48 column) - and diffed them pin by pin. Zero mismatches, including OSC_IN/OSC_OUT, NRST, PA11/PA12 for USB, PA13/PA14 for SWD, and BOOT0. Power pins differ only in naming. This was the one unverified assumption the whole project rested on: three boards laid out to a footprint that has to accept either MCU. It holds. Full table recorded in Documents/pinout-L103-vs-F103.md. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Documents
Diagrams, the BOM, and the datasheets for parts this design actually depends on.
Diagrams
| File | Shows |
|---|---|
three-board-overview.svg |
All three boards at the same key spacing |
half-left-staggered.svg |
Left half — 34 keys, six clean columns |
half-right-staggered.svg |
Right half — 41 keys |
numpad-layout.svg |
Numpad — 25 keys plus the volume encoder |
104-key-split.svg |
How a full 104 maps across the three boards |
half-left.svg, half-right.svg |
The earlier row-staggered split, kept for reference |
bom.csv carries LCSC part numbers, JLC basic/extended status and the
swap-dependent parts. pinout-L103-vs-F103.md is the 48-pin overlay that
validates the dual-MCU footprint.
Datasheets
Only the parts this design 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. |
STM32F103x8xB_datasheet_rev1.PDF |
STM32F103C8T6 | The pin-compatible escape-hatch MCU. Source for the LQFP48 pin overlay, now done — see pinout-L103-vs-F103.md. |
⚠️ The STM32F103 copy is Rev 1 (preliminary)
st.com refuses scripted download (HTTP/2 reset on curl; its CSP also blocks exfiltrating a browser-side fetch). This copy came from a third-party mirror and is the early preliminary revision, 65 pages — the current one is Rev 20 at ~117 pages.
For the LQFP48 pin numbering it is fine, and the overlay has now been done against it: that table has not changed since 2007, and PC13/PC14/PC15, OSC_IN/OSC_OUT, NRST, PA11/PA12, PA13/PA14 and BOOT0 are all present and verified in this copy.
Do not trust it for anything electrical — absolute maximums, timings, current consumption and errata have all moved since Rev 1. For those, pull the current datasheet by hand from https://www.st.com/resource/en/datasheet/stm32f103c8.pdf in a browser and replace this file.