IMU-Bridge Integration Tools
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get_component_notes("icm20689") 已成功返回。Table
| 项目 | 返回内容 |
|---|---|
| 重要警告 | 没有 CPOUT 引脚，任何 “CPOUT 电容” 描述都应忽略 |
| REGOUT | Pin 10 -> 0.47 µF X7R ±10% |
| VDD | Pin 9 -> 2.2 µF + 100 nF |
| VDDIO | Pin 8 -> 10 nF |
| nCS | Pin 22 -> 直接接 VDD，进入 I2C 模式，不加电容 |
| FSYNC | Pin 7 -> 接 GND，不可悬空 |
| I2C 地址 | AD0=GND -> 0x68；AD0=VDD -> 0x69 |
| WHO_AM_I | 0x98 |
| NC 引脚 | INT / CLKIN / AUX_DA / AUX_CL 悬空，严禁接 GND |
| 热焊盘 | 中央 EP 焊盘必须接 GND |
- FSYNC 不是 NC，必须接地
- nCS 是 Pin 22，不是 Pin 20，并且应直接接 VDD
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IMU-Bridge-2026 · Flux Design Document v2
Dual MPU-6050 I2C Transparent Proxy Board for BaseCam AC2000
Version: v2.0 · 2026-04-14 · Lessons-learned revision
What changed from v1: This revision incorporates every issue encountered during the
first Flux AI session. The scope is now limited to schematic only. PCB routing is
explicitly out of scope and will be handled separately. Part substitutes are pre-approved.
No-Connect handling is clearly separated into what AI can do vs. what requires manual action.
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Pre-flight: Library Availability Run these searches in the Flux component library before starting. Use the substitute if the primary part is not found. Do not ask — just use the substitute listed. Primary PartFlux Library?Approved SubstituteNotesMPU-6050 QFN-24❌ Not availableICM-20689 QFN-24Same package, same I2C scheme, same data registers 0x3B–0x48STM32G030F6P6 TSSOP-20✅ Available——AMS1117-3.3 SOT-223✅ AvailableLM1117-3.3 SOT-223Same pinoutJST GH 1.25 mm 5-pin✅ Available——0402 / 0805 passives✅ Available—Standard values If a part is not found and no substitute is listed, stop and report — do not guess.
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Project Overview This board replaces the stock IMU board (single MPU-6050) on a BaseCam AC2000 gimbal. SimpleBGC 32-bit firmware is closed-source and cannot be modified. Solution: STM32G030F6P6 as I2C transparent proxy
I2C1 (PA9/PA10) = Slave, main bus, responds to address 0x68
I2C2 (PB6/PB7) = Master, secondary bus, manages IMU#1 (0x68) and IMU#2 (0x69)
Board: 25.80 × 20.80 mm · JST GH 1.25 mm 5-pin · +5V input · 3.3V on-board
Scope of this document: Schematic only.
PCB routing is out of scope and will be handled by a separate contractor.
- Complete BOM
All capacitor and resistor values are exact. Do not substitute based on RAG suggestions.
CPOUT = 2.2 nF — this is the most commonly hallucinated value; do not change it.
RefDesMPN / ValuePackageQtyNotesU1STM32G030F6P6TSSOP-20148 MHz, dual I2CU2ICM-20689 (substitute for MPU-6050)QFN-24 4×4 mm1I2C addr 0x68, AD0=GNDU3ICM-20689 (substitute for MPU-6050)QFN-24 4×4 mm1I2C addr 0x69, AD0→R6→3.3VU4AMS1117-3.3SOT-22315V → 3.3V LDOJ1JST GH 1.25 mm 5-pinSMD horizontal1Pin order: +5V/GND/SCL/SDA/AUX1C110 µF / 10 V0805 MLCC X5R1AMS1117 VIN bulkC2100 nF / 16 V0402 MLCC1AMS1117 VIN bypassC310 µF / 10 V0805 MLCC X5R1AMS1117 VOUT bulkC4100 nF / 16 V0402 MLCC1AMS1117 VOUT bypassC5100 nF / 10 V0402 MLCC1STM32 VDD bypassC6100 nF / 10 V0402 MLCC1STM32 NRST filterC7100 nF / 10 V0402 MLCC1U2 VCC bypassC8100 nF / 10 V0402 MLCC1U3 VCC bypassC9100 nF / 10 V0402 MLCC1U2 REGOUT filterC10100 nF / 10 V0402 MLCC1U3 REGOUT filterC112.2 nF / 10 V0402 MLCC1U2 CPOUT — must be 2.2 nFC122.2 nF / 10 V0402 MLCC1U3 CPOUT — must be 2.2 nFR14.7 kΩ04021Main bus SCL pull-up → 3.3VR24.7 kΩ04021Main bus SDA pull-up → 3.3VR34.7 kΩ04021Sub bus SCL pull-up → 3.3VR44.7 kΩ04021Sub bus SDA pull-up → 3.3VR510 kΩ04021BOOT0 pull-down → GNDR610 kΩ04021U3 AD0 pull-up → 3.3VMH1–MH4—2.2 mm NPTH4M2 mounting holesTP1–TP4—0.9 mm via pad43.3V / GND / SWD_CLK / SWD_IO
- Power Network J1.Pin1 (+5V) ──→ AMS1117 VIN ──┬── C1 (10 µF) ──→ GND └── C2 (100 nF) ──→ GND
AMS1117 VOUT (VCC_3V3) ──────────┬── C3 (10 µF) ──→ GND
└── C4 (100 nF) ──→ GND
J1.Pin2 (GND) ──→ GND plane
PinNetU1 VDD (all VDD pins)VCC_3V3 + C5 100 nF next to pinU1 VSS (all VSS pins)GNDU1 NRSTC6 100 nF → GNDU2 VDD (Pin 3, 13, 24), VDDIO (Pin 8)VCC_3V3 + C7 100 nF next to pinU2 GND (Pin 2, 17, 18, 21, 22, 23), EPGNDU3 VDD (Pin 3, 13, 24), VDDIO (Pin 8)VCC_3V3 + C8 100 nF next to pinU3 GND (Pin 2, 17, 18, 21, 22, 23), EPGND
- Signal Network (using ICM-20689 pin names) 4.1 Main I2C Bus — J1 to STM32 Slave SignalJ1 PinSTM32 PinPull-upMAIN_SCLPin 3PA9 (I2C1_SCL)R1 4.7 kΩ → VCC_3V3MAIN_SDAPin 4PA10 (I2C1_SDA)R2 4.7 kΩ → VCC_3V3 4.2 Secondary I2C Bus — STM32 Master to U2 and U3 SignalSTM32 PinU2 PinU3 PinPull-upSUB_SCLPB6 (I2C2_SCL)Pin 23 (SCL/SCLK)Pin 23 (SCL/SCLK)R3 4.7 kΩ → VCC_3V3SUB_SDAPB7 (I2C2_SDA)Pin 24 (SDA/SDI)Pin 24 (SDA/SDI)R4 4.7 kΩ → VCC_3V3 4.3 ICM-20689 Per-pin Wiring Apply identically to both U2 and U3 except AD0: ICM-20689 PinNameConnect ToValuePin 9AD0/SDOU2 → GND · U3 → R6 (10 kΩ) → VCC_3V3sets addr 0x68 / 0x69Pin 10REGOUTC9/C10 (100 nF) → GNDfilter capPin 11FSYNCGNDnot usedPin 12INTleave unconnected — symbol already marks as NCdo not wirePin 19CLKINleave unconnected — symbol already marks as NCdo not wirePin 20nCSC11/C12 (2.2 nF) → GNDCPOUT placeholderPin 6AUX_DAleave unconnected — symbol already marks as NCdo not wirePin 7AUX_CLleave unconnected — symbol already marks as NCdo not wire
Note on NC-typed pins: The ICM-20689 symbol in Flux types INT, CLKIN, AUX_DA, AUX_CL
as NC. Do not attempt to connect these to GND — doing so causes an ERC violation
("no-connect pin connected"). Leave them untouched.
4.4 STM32 Remaining Connections
SignalPinNetBOOT0BOOT0 pinR5 (10 kΩ) → GNDSWD_IOPA13TP4SWD_CLKPA14TP33V3 test point—TP1 → VCC_3V3GND test point—TP2 → GND
4.5 J1 Connector
PinNet1+5V2GND3MAIN_SCL4MAIN_SDA5Unconnected — add No-Connect marker manually after AI step
- No-Connect Handling
Important: Flux Copilot cannot place No-Connect markers. This is a manual step.
The table below separates what the symbol handles automatically vs. what needs manual action.
Handled automatically by the ICM-20689 symbol (no action needed)
INT · CLKIN · AUX_DA · AUX_CL — already typed as NC in the symbol.
Requires manual No-Connect markers after AI completes schematic
ComponentPinsJ1Pin 5 · Pin 6 · Pin 7U1 (STM32)PC14/PB9 · PC15 · PA0 · PA1 · PA2 · PA3 · PA4 · PA5 · PA6 · PA7 · PB0/PB1/PB2/PA8U2, U3 (ICM-20689)INT (Pin 12)
How to add manually in Flux: Right-click the unconnected pin end → look for "No Connect"
in the context menu. If not available, accept the ERC warnings — they do not affect netlist
correctness or PCB routing.
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PCB Mechanical Constraints (For reference — to be handed to PCB layout contractor) ParameterValueBoard size25.80 × 20.80 mmLayers2Thickness1.6 mmSurface finishHASL-LF or ENIGBoard-edge keep-out0.3 mm Mounting holes (NPTH, dia = 2.2 mm, keep-out = 0.5 mm): RefDesX (mm)Y (mm)MH12.02.0MH22.018.8MH323.82.0MH423.818.8 Routing rules (for contractor): Net classWidthNotesPower (5V, 3V3)≥ 0.3 mm—I2C signals0.15 mmEqual-length pairs, no acute anglesOther signals0.1 mm—Clearance0.15 mmAll copperGND pourBoth layersThermal relief, clearance 0.15 mm
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Acceptance Criteria for Schematic CheckTargetNotesERC real errors0Floating-pin warnings on manually-skipped NC pins are acceptableAll BOM nets connected100%Verify with ERC net checkCPOUT cap value2.2 nFVerify C11 and C12 before signing offU2 AD0GNDAddr = 0x68U3 AD0R6 → 3.3VAddr = 0x69J1 pin 1–4Wired+5V / GND / MAIN_SCL / MAIN_SDA
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Export Checklist (after schematic is complete) ExportMenu pathRecipientSchematic NetlistFile → Export → Schematic Netlist (.edif)PCB layout contractorBill of MaterialsFile → Export → Bill of Materials (.zip)PCB layout contractorFlux projectFile → Export → Flux project (.flx)PCB layout contractor (board outline + holes included)Manufacturing FilesFile → Export → Manufacturing Files (Gerbers)PCB fab — only after routing is done
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Master Schematic Command (Paste into Flux Copilot Chat after uploading this document) Read this entire document. Execute the schematic design below in order. Scope: schematic only — do not attempt PCB routing.
① [Library check]
Search the Flux library for each part in Section 2 BOM.
Use ICM-20689 QFN-24 for U2 and U3 — MPU-6050 is not available.
If any other part is not found, stop and report before proceeding.
② [Add all components]
Place all parts from Section 2 with correct footprints:
U1 = STM32G030F6P6 TSSOP-20
U2, U3 = ICM-20689 QFN-24 (4×4 mm)
U4 = AMS1117-3.3 SOT-223
J1 = JST GH 1.25 mm 5-pin SMD horizontal
C1, C3 = 10 µF 0805; all other caps = 0402
All resistors = 0402
MH1–MH4 = 2.2 mm NPTH mounting holes
TP1–TP4 = test point pads
③ [Wire power network]
Wire the complete power network per Section 3:
J1.Pin1 → AMS1117 VIN → C1 + C2 → GND
AMS1117 VOUT (VCC_3V3) → C3 + C4 → GND
VCC_3V3 → U1 all VDD pins (with C5 bypass)
VCC_3V3 → U2 VDD + VDDIO pins (with C7 bypass)
VCC_3V3 → U3 VDD + VDDIO pins (with C8 bypass)
U1 NRST → C6 → GND
All VSS/GND pins → GND
J1.Pin2 → GND
④ [Wire signal network]
Wire all signal nets per Section 4:
- Main I2C bus: J1.Pin3 → R1 → PA9; J1.Pin4 → R2 → PA10
- Sub I2C bus: PB6 → R3 → U2.Pin23 + U3.Pin23; PB7 → R4 → U2.Pin24 + U3.Pin24
- U2 AD0 (Pin9) → GND
- U3 AD0 (Pin9) → R6 (10 kΩ) → VCC_3V3
- U2 + U3: Pin10 (REGOUT) → C9/C10 (100 nF) → GND
- U2 + U3: Pin11 (FSYNC) → GND
- U2 + U3: Pin20 (nCS, used as CPOUT) → C11/C12 (2.2 nF) → GND
- BOOT0 → R5 (10 kΩ) → GND
- PA13 → TP4; PA14 → TP3
- TP1 → VCC_3V3; TP2 → GND
⑤ [NC-typed pins — do nothing]
Do NOT connect or add No-Connect markers to these pins — they are already
typed as NC in the ICM-20689 symbol and will cause ERC violations if touched:
U2 + U3: INT (Pin12), CLKIN (Pin19), AUX_DA (Pin6), AUX_CL (Pin7)
⑥ [ERC]
Run ERC. Fix all real connection errors.
Floating-pin warnings on unused STM32 GPIOs and J1 Pin5 are acceptable
(No-Connect markers for those will be added manually — Copilot cannot place them).
Report the final ERC result.
⑦ [Report]
List:
- Any parts that were substituted and why
- Any nets that could not be wired and why
- Final ERC error count and warning count
- Pins that still need manual No-Connect markers
