tertiary/docs/bom.csv at 4467aa9433491e01849bb66fb08bd0f678379d86

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William RickertandClaude Opus 5 4467aa9433 Initial design record for the three-piece keyboard

Two mirrored halves plus a numpad that carries the USB hub. Captures the
architecture decisions and the reasoning behind them: CH32L103 with an
STM32F103 pin-compatible escape hatch, split protocol tunnelled over USB-C
SBU through the numpad, hotswap sockets bottom-side, and why crystal-less
USB was ruled out across the whole WCH catalogue.

No boards ordered, no firmware written. Layout still undesigned.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

2026-08-27 14:07:50 -05:00

5.2 KiB

Raw Blame History

1	Board	Section	Ref	Qty	Value	MPN	LCSC	Package	JLC	Unit USD	Notes
2	ALL	MCU	U1	1	CH32L103C8T6	CH32L103C8T6	C22398291	LQFP-48(7x7)	Extended	0.80	MCU. Swap-compatible: STM32F103C8T6 = C8734 / Preferred / $1.44
3	ALL	MCU	U2	1	3.3V LDO 500mA	RT9013-33GB-MS	C7434207	SOT-23-5	Extended	0.06	Alt basic: XC6206P332MR-G C5446 but only 200mA
4	ALL	MCU	U3	1	USB ESD	USBLC6-2SC6	C2687116	SOT-23-6	Extended	0.048	on this board's own USB-C
5	ALL	MCU	J1	1	USB-C 16P	TYPE-C16PIN	C393939	SMD	Extended	0.069	upstream / device port
6	ALL	MCU	J2	1	SWD header	-	-	1.27mm 4-pin	Consigned	0.00	SWDIO=PA13 SWCLK=PA14 GND 3V3
7	ALL	MCU	Y1	1	8MHz crystal	TAXM8M4RDBCCT2T	C400090	SMD3225-4P	Extended	0.146	10pF load 250R ESR +/-10ppm. Satisfies both MCUs' USB PLL
8	ALL	MCU	SW1	1	Tactile RESET	TS2306A 200gf	C5363482	SMD 3x2mm	Extended	0.062	to NRST
9	ALL	MCU	SW2	1	Tactile BOOT	TS2306A 200gf	C5363482	SMD 3x2mm	Extended	0.062	BOOT0 to 3V3. Works for both boot paths
10	ALL	MCU	C1-C5	5	100nF 0402 X7R 16V	CL05B104KO5NNNC	C1525	0402	Basic	0.006	VDD_1 VDD_2 VDD_3 VDDA NRST
11	ALL	MCU	C6	1	4.7uF 0603 X5R	CL10A475KO8NNNC	C19666	0603	Basic	0.024	bulk at MCU
12	ALL	MCU	C7	1	1uF 0402 X5R 25V	CL05A105KA5NQNC	C52923	0402	Basic	0.014	VDDA
13	ALL	MCU	C8-C9	2	10uF 0805 X5R	CL21A106KAYNNNE	C15850	0805	Basic	0.077	LDO input and output
14	ALL	MCU	C10-C11	2	12pF 0402 C0G	JLC basic library	-	0402	Basic	0.005	MCU crystal load. 12pF assumes 10pF CL + ~4pF stray - verify vs stackup
15	ALL	MCU	R1-R2	2	22R 0402	FRC0402F22R0TS	C2929994	0402	Extended	0.0007	USB D+/D- series. 0R (C17168 Basic) also acceptable
16	ALL	MCU	R3-R4	2	5.1k 0402	JLC basic library	-	0402	Basic	0.002	USB-C CC1/CC2 pull-DOWN (Rd - device side)
17	ALL	MCU	R5	1	1.5k 0402	JLC basic library	-	0402	Basic	0.002	* SWAP-DEPENDENT * D+ pull-up. POPULATE for STM32F103. DNF for CH32L103 (internal 1.5k via RB_UC_DEV_PU_EN)
18	ALL	MCU	R6-R7	2	10k 0402	FRC0402F1002TS	C25744	0402	Basic	0.003	BOOT0 pulldown, BOOT1/PB2 pulldown
19	HALF	Matrix	D1-Dn	1	1N4148W	1N4148W	C81598	SOD-123	Basic	0.011	One per key. Qty per your layout
20	HALF	Split	R14	1	100R 0402	JLC basic library	-	0402	Basic	0.002	Series on the SBU net between connector and MCU USART pin
21	HALF	Split	D-ESD	1	ESD 5V bidirectional	PESD5V0S1BA	C2827694	SOD-323	Extended	0.036	On the SBU net - user-exposed signal going to a GPIO
22	HALF	Split	J3	1	3-pin header DNF	JST SH	-	-	Consigned	0.02	* DNF INSURANCE * VCC/GND/DATA fallback if SBU proves flaky (bad cables). 3 pads cost nothing
23	HALF	Split	-	-	SBU1+SBU2 TIE	-	-	-	-	0.00	Tie A8 and B8 together on the board. SBU is CROSSED in the cable, so this makes it orientation-proof and doubles the conductor
24	NUMPAD	DNF	J1/U3/R3/R4/R5	0	DO NOT POPULATE	-	-	-	-	0.00	*** From the ALL block: numpad MCU has NO connector of its own. Its D+/D- route internally to hub downstream port 1. No connector = no ESD part and no CC resistors needed. Saves ~$0.19
25	NUMPAD	Matrix	D1-D26	26	1N4148W	1N4148W	C81598	SOD-123	Basic	0.011	26 keys: 17 numpad + 9 nav
26	NUMPAD	Encoder	ENC1	1	EC11 detented	EC11L1525G01	C2991196	THT	Extended	1.27	VOLUME - wants detents. THT: hand-solder or JLC THT surcharge
27	NUMPAD	Encoder	ENC2	1	EC11 detentless	verify variant	-	THT	Extended	1.27	SCROLL - wants NO detents for hi-res scroll. Confirm detentless SKU
28	NUMPAD	Hub	U4	1	USB2.0 4-port hub	CH334R	C4154405	QSOP-16-150mil	Extended	0.50	Ports: 1=own MCU (internal FS) 2=left half 3=right half 4=spare
29	NUMPAD	Hub	Y2	1	12MHz crystal	X322512MSB4SI	C9002	SMD3225-4P	Basic	0.101	CH334 has built-in load caps - verify internal value vs this 20pF CL crystal; fit DNF cap pads
30	NUMPAD	Hub	C12-C14	3	100nF 0402	CL05B104KO5NNNC	C1525	0402	Basic	0.006	hub decoupling
31	NUMPAD	Hub	C15	1	10uF 0805	CL21A106KAYNNNE	C15850	0805	Basic	0.077	hub bulk
32	NUMPAD	Hub	J4	1	USB-C upstream	TYPE-C16PIN	C393939	SMD	Extended	0.069	to PC. This replaces J1 as the board's real upstream
33	NUMPAD	Hub	J5-J7	3	USB-C downstream	TYPE-C16PIN	C393939	SMD	Extended	0.069	left half / right half / spare
34	NUMPAD	Hub	U5-U7	3	USB ESD	USBLC6-2SC6	C2687116	SOT-23-6	Extended	0.048	one per downstream port
35	NUMPAD	Hub	U8-U10	3	Ideal diode / OCP	CH213K	C5456874	SOT-23-3	Extended	0.073	VBUS protection per downstream port. CH334R has no port power switching
36	NUMPAD	Hub	R8-R13	6	56k 0402	FRC0402F5602TS	C2906875	0402	Extended	0.0018	Rp pull-UPS on CC1/CC2 of each downstream port - host side. NOT 5.1k
37	NUMPAD	SBU	-	-	SBU PASS-THROUGH	-	-	-	-	0.00	* Passive trace * Tie SBU1+SBU2 on J5 (left half) and on J6 (right half), then connect the two nets together. Carries QMK split_common UART between the halves. Numpad MCU does NOT touch this net
38	NUMPAD	SBU	D-ESD2	2	ESD 5V bidirectional	PESD5V0S1BA	C2827694	SOD-323	Extended	0.036	One per half-port SBU net
39	HALF	Switches	SW-	1	MX hotswap socket	CPG151101S11	C41430893	SMD 14.5x5.9mm	Extended	0.037	One per key. BOTTOM SIDE. Alt: C49352235 (CPG151101S11-2)
40	NUMPAD	Switches	SW-	26	MX hotswap socket	CPG151101S11	C41430893	SMD 14.5x5.9mm	Extended	0.037	One per key. BOTTOM SIDE
41	NOTE	Assembly	-	-	SINGLE-SIDED	-	-	-	-	-	Put ALL SMD on the BOTTOM: sockets, MCU, passives, diodes, and any reverse-mount SK6812MINI-E. Top face bare except switch holes. Keeps JLC to one assembly pass
42	NOTE	Mechanical	-	-	PLATE REQUIRED	-	-	-	-	-	Hotswap needs a switch plate or socket pads tear off during switch insertion. FR4 plate = just another JLC board

5.2 KiB Raw Blame History

5.2 KiB

Raw Blame History