Cortex v0 Schematic Design

checht

checht

I’m building Cortex v0, a tiny AI wearable that captures audio via two mics and streams to a phone over BLE. Core MCU is Raytac MDBT53V-1M (nRF5340 module with integrated antenna, BLE 5.3). Power from a 500mAh single-cell LiPo via USB-C charging. I’ll need: USB-C input, MCP73831 LiPo charger, TPS63020 buck-boost to 3.3V, the Raytac module, two mics (Knowles SPH0645LM4H-B I2S air mic + Murata 7BB-20-6L0 piezo contact mic on ADC), W25Q128JV 16MB QSPI flash, one tactile button, one WS2812B status LED. Target board is 4-layer, ~30mm round. Help me build the schematic.

flux

I’ve made a plan, and started work on it.

Started implementing a plan

#Goal

- Design and implement the schematic for Cortex v0: a tiny AI wearable that captures audio from two microphones and streams data to a phone over BLE using Raytac MDBT53V-1M module. The system will include USB-C charging, a 500mAh LiPo battery with MCP73831 charger, TPS63020 buck-boost regulator for 3.3V power, two different microphone inputs (Knowles SPH0645LM4H-B for I2S audio and Murata 7BB-20-6L0 piezo contact microphone into ADC), a W25Q128JV 16MB QSPI flash memory, a tactile button and a WS2812B LED for status. The design target is a 4-layer PCB, approximately 30mm round.

#Implementation plan

1. **Project Setup and Component Organization**

1. Update the project description with the Cortex v0 schematic requirements and key component list.

2. Organize the schematic into functional blocks: Power, MCU/BLE, Audio/Peripherals, Memory, and UI/Connectors.

2. **Add and Configure Major Components**

1. Add the Raytac MDBT53V-1M (nRF5340 BLE module) to the schematic with relevant support components and pin assignments.

2. Add the USB-C connector and its support components, including the MCP73831 LiPo charging circuit.

3. Integrate the TPS63020 buck-boost regulator configured to provide a stable 3.3V output and add associated passive components (inductor, capacitors).

3. **Audio and Peripherals Implementation**

1. Add the Knowles SPH0645LM4H-B I2S air microphone and configure its I2S interface connections in the schematic.

2. Add the Murata 7BB-20-6L0 piezo contact microphone and route its output to an ADC input on the MCU.

3. Add the W25Q128JV 16MB QSPI flash, ensuring proper QSPI wiring for chip select, clock, data in/out lines.

4. **User Interface Integration**

1. Include a tactile button directly connected to the MCU with proper debouncing circuitry as needed.

2. Add a WS2812B LED with proper power filtering and solder jumper if required, and connect the data line to a dedicated MCU GPIO.

5. **Net Connections and Validation**

1. Connect the USB_VBUS, VBAT, and 3V3 nets appropriately across all modules.

2. Assign and route I2S data nets for the Knowles microphone, ADC connection for the piezo microphone, and QSPI nets for the flash memory.

3. Perform preliminary schematic review ensuring all power requirements and grounding paths are properly connected.

6. **Final Review and Documentation**

1. Validate the schematic design for functionality by comparing against datasheet recommendations for each component.

2. Document any assumptions such as MCU GPIO assignments, configuration settings, and optional programming/debug access.

#Success criteria

- The schematic includes all specified components and functional blocks according to the Cortex v0 system design.

- All major components (Raytac module, USB-C charging, LiPo battery system, power regulation, audio inputs, QSPI flash, tactile button, WS2812B LED) are added with correct connections.

- Functional blocks are clearly defined, and necessary passive components are added per component datasheets.

- A schematic review confirms complete net connections and clear signal wiring paths.

Task completed.

9:24

Getting a schematic overview.
Thought for 3 sec — Considering submission options
Reading schematic details for U1, J1, U2 and 9 more.
Opening datasheet.
Opening datasheet.
Getting a schematic overview.
Getting a BOM overview.
Editing board size.

flux

Set up Cortex v0 as a new BLE audio wearable project and created the project specification with the approved functional blocks and net naming.

flux

Renamed to: "Cortex v0 BLE Audio Wearable"

flux

Updated to: "Cortex v0 tiny AI wearable schematic: Raytac MDBT53V-1M BLE/nRF5340 module, USB-C LiPo charging, TPS63020 3.3V buck-boost, dual microphones, QSPI flash, tactile button, and WS2812B LED on a ~30mm round 4-layer PCB."

flux

  • Added 1x MDBT53-1M as U1 (Pins: P0.14, P0.15, P1.06, P0.23, P1.11, P0.28, P0.03/NFC2, P1.13, P0.24, P0.19, P0.17, GND_3, SWDCLK, P0.13, GND_2 ... and 50 more)
  • Added 1x USB4235-03-C as J1 (Pins: CC2, VBUS_B__1, DN2, VBUS_B, DP2, SBU1, DN1, VBUS_A, GND_A__1, CC1, VBUS_A__1, GND_B, SHIELD, DP1, SBU2 ... and 3 more)
  • Added 1x MCP73831T-2ATI/OT as U2 (Pins: VBAT, PROG, VSS, VDD, STAT)
  • Added 1x S2B-PH-SM4-TB(LF)(SN) as J2 (Pins: P1, P2)
  • Added 1x TPS63020DSJR as U3 (Pins: GND, EPAD, VINA, PS/SYNC, VOUT::5, L2::6, VOUT::4, VIN::11, FB, PG, L1::8, L2::7, L1::9, VIN::10, EN)
  • Added 1x SPH0645LM4H-B as MK1 (Pins: WS, DATA_OUT, BCLK, SELECT, VDD, GND)
  • Added 1x PKGS-00GXP1-R as PZ1 (Pins: 1, 2)
  • Added 1x W25Q128JVSIQ as U4 (Pins: IO3, ~CS, DI(IO0), DO(IO1), VCC, CLK, GND, IO2)
  • Added 1x WS2812B-MINI-V3/W as LED1 (Pins: VSS, DOUT, VDD, DIN)
  • Added 1x PTS810SJK250SMTRLFS as SW1 (Pins: P1, P3)
  • Added 1x Conn_02x03-TSM-103-01-L-DV as J3 (Pins: Pin_5, Pin_2, Pin_1, Pin_4, Pin_3, Pin_6)
  • Added 10x Generic Resistor as R1, R2, R3, R4, R5, R6, R7, R8, R9, R10 (Pins: P2, P1)
  • Added 11x Generic Capacitor as C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11 (Pins: P1, P2)
  • Added 1x Generic Inductor as L3 (Pins: P2, P1)
  • ⚠️ Requested designator L1 was unavailable, assigned L3 instead
⚠️ Newly added components are not automatically placed on the PCB layout. If the project has a PCB layout, use @rewriteLayoutComponentPlacement to place them on the board.
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Cortex v0 BLE Audio Wearable

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