BLE RGB LED Board
keep working til it's finished please
Thought for 10 sec
I’ll keep going: first I’ll open up the congested power/charger area, then continue routing remaining power, debug, reset, and status nets, with checks after each cleanup pass.
Worked for 1 min 51 sec
I’m blocked now because the account has no available ACUs, so I can’t continue executing layout/routing actions.
Accomplished in this session:
- Re-checked the routing state and confirmed the main blocker is still the tight charger/battery area around U2/J2.
- Removed leftover conflicting SWD trace segments that were causing copper-overlap problems.
- Expanded the board from 80×40 mm to 90×42 mm to improve routing space and reduce density.
Open items:
- Re-place/spread U2, J2, R5/R7/R8/R9, U3, U5, and nearby passives into the new extra space.
- Continue routing remaining airwires, especially BAT_PLUS, VBUS, SYS, LED_VDD, 3V3/GND, LED_EN, RESET_N, PGOOD_N, SWD, and USB D+/D− reserved/ESD lines.
- Run DRC after routing and clean any remaining conflicts.
- Update the Layout Plan after the next completed routing pass.
Check ACUs
List routing blockers
Suggest charger placement
Run DRC
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Project Specification — BLE RGB LED Display
Project Overview
Status: Draft. Compact rechargeable BLE-controlled 4x8 RGB LED display board using an ANNA-B112 BLE module, 32 SK6812MINI-E addressable RGB LEDs, USB-C charging, and a single-cell LiPo battery.
Intended Use
Prototype wearable/portable LED display or indicator. The board is intended for low-to-moderate brightness animations controlled over Bluetooth Low Energy.
What the Device Should Do
- Receive BLE commands.
- Drive a 4x8 RGB LED display.
- Recharge from a USB-C 5 V source.
- Operate from a thin single-cell protected LiPo pack.
- Report charge status, power-good state, and battery voltage to firmware.
- Allow SWD programming/debug.
Main Features
- BLE: ANNA-B112-01B nRF52832-based module.
- Display: 32x SK6812MINI-E pixels in a 4x8 logical matrix.
- Power: USB-C sink input, BQ24074 charger/power-path IC, TPS78233 3.3 V LDO.
- LED rail: MP5075 load switch controlled by firmware, SN74LVC1T45 data level shifter.
- Protection/debug: USB/ESD protection, reset switch, SWD header.
System Architecture
Diagram
Hardware Subsystems
- USB-C input: sink-only USB-C power input with CC pull-downs and ESD protection. USB data is reserved/not used.
- Charging/power path: BQ24074 powers SYS and charges a 1-cell LiPo.
- BLE control: ANNA-B112 module runs application firmware and handles BLE communication.
- LED display: SK6812MINI-E LEDs daisy-chain data from D1 through D32.
- LED power control: MP5075 gates LED power; firmware should default LEDs off until battery/SYS conditions are safe.
- Debug/programming: SWD header and reset switch.
Interfaces and Connections
Table
| Interface | Nets / Components | Notes |
|---|---|---|
| USB-C power | J1, VBUS, GND, CC1, CC2 | Power-only sink; no USB PD. |
| Battery | J2, BAT_PLUS, BAT_NTC, GND | Requires approved protected 1-cell pack and verified connector polarity. |
| SWD | J3, SWDIO, SWDCLK, RESET_N, 3V3, GND | Programming/debug. |
| LED data | LED_DATA_RAW, LED_DATA_SHIFTED, LED_DIN_1 | BLE module drives level shifter; shifted data drives D1. |
| Status | CHG_STAT_N, PGOOD_N | Active-low charger/power-good signals to MCU. |
| Battery sense | VBAT_ADC | Divider + filter to MCU ADC. |
Power and Runtime Expectations
Runtime is dominated by LED brightness. Full-white theoretical LED current can approach about 1.9 A for 32 pixels at 60 mA/pixel, so long battery life requires firmware current limiting and low average brightness.
Power Tree and Power Budget
See the separate Power and Runtime Notes file for detailed current modes and battery-life assumptions.
Manufacturing and Assembly Expectations
- Intended as a compact prototype PCB, likely 4-layer for RF/power/return-path quality.
- All external connector pinouts and footprints must be verified before fabrication.
- RF antenna geometry and keepout must be checked against the u-blox integration guidance before ordering boards.
Firmware-Relevant Hardware Requirements
- Keep LED_EN low at boot, reset, debugger halt, and brownout when possible.
- Measure VBAT_ADC before and during LED operation.
- Use brightness/current limiting; avoid sustained full-white operation.
- Advertise/connect over BLE and accept display commands.
- Use SWD for flashing/recovery.
Physical Design Expectations
- Compact board with LEDs arranged as a clear 4x8 matrix.
- BLE module antenna at board edge with required keepout/tuning geometry.
- USB-C accessible at an edge.
- Battery connector accessible but mechanically protected.
- Thin battery should sit behind or beside the board without intruding into antenna keepout.
Important Design Decisions
- BLE module instead of discrete RF design to reduce RF risk.
- BQ24074 selected for integrated charger and power-path behavior.
- Direct LiPo/SYS-powered LED rail selected for compactness, accepting reduced guaranteed LED behavior near low battery.
- Hardware LED power switch included so firmware can completely remove LED power.
Assumptions
- Battery is a protected 1-cell LiPo with compatible NTC and connector polarity.
- USB-C is used for 5 V power only.
- The display will normally run at reduced brightness to meet runtime and thermal goals.
- ANNA-B112 lifecycle/variant suitability is still to be confirmed.
Change Notes
- Initial schematic created with BLE, charger, power path, 3.3 V rail, LED chain, level shifter, battery monitor, SWD, reset, and protection blocks.
- Current layout is not production-ready; it still needs compact placement, routing, antenna implementation, and DRC cleanup.
Project Overview
Intended Use
What the Device Should Do
Main Features
System Architecture
Hardware Subsystems
Interfaces and Connections
Power and Runtime Expectations
Power Tree and Power Budget
Manufacturing and Assembly Expectations
Firmware-Relevant Hardware Requirements
Physical Design Expectations
Important Design Decisions
Assumptions
Change Notes
