Using MicroMod M.2 Connectors

SparkFun MicroMod processor boards plug into carrier boards through a keyed M.2 edge connector. In tscircuit, model the connector as a reusable <connector /> wrapper: import or define the exact M.2 footprint, assign selector-safe names to the official MicroMod pins, then connect your carrier board circuits to those names.

Use the SparkFun references as the source of truth while checking your work:

• MicroMod Interface pin descriptions
• MicroMod Interface pinout
• MicroMod graphical datasheet
• MicroMod product family
• Getting started with MicroMod

Workflow

1. Pick the MicroMod processor board first. Each board can map processor features differently onto the shared connector.
2. Import the connector footprint from KiCad or a supplier footprint. See Importing from KiCad and Importing from JLCPCB for those flows.
3. Wrap the imported footprint with a MicroModConnector component so the rest of your board connects to names like I2C_SDA, SPI_COPI, USB_D_P, and V3_3 instead of raw pad numbers.
4. Connect only the buses your carrier board needs. Leave processor-specific or unused pins unconnected unless the processor board documentation says a pull-up, pull-down, test point, or keepout is required.
5. Before ordering boards, compare the generated Gerbers against the SparkFun pinout PDF, the graphical datasheet, and the connector manufacturer's land pattern. The module key, insertion direction, and top-side pad numbering are easy to mirror by accident.

Pin-label scaffold

The labels below are based on SparkFun's MicroMod Interface v1.0 pinout. They use selector-safe names, so USB_D+ becomes USB_D_P, active-low pins use _N, and 3.3V becomes V3_3.

export const MicroModConnector = (props: {
  name: string
  footprint: any
}) => (
  <connector
    name={props.name}
    standard="m2"
    footprint={props.footprint}
    pinLabels={{
      pin1: "GND",
      pin2: "V3_3",
      pin3: "USB_D_P",
      pin4: "V3_3_EN",
      pin5: "USB_D_N",
      pin6: "RESET_N",
      pin7: "GND",
      pin8: "G11_SWD_SWO",
      pin9: "USB_VIN",
      pin10: "D0",
      pin11: "BOOT",
      pin12: "I2C_SDA",
      pin13: "UART_RTS1",
      pin14: "I2C_SCL",
      pin15: "UART_CTS1",
      pin16: "I2C_INT_N",
      pin17: "UART_TX1",
      pin18: "D1_CAM_TRIG",
      pin19: "UART_RX1",
      pin20: "UART_RX2",
      pin21: "SWDCK",
      pin22: "UART_TX2",
      pin23: "SWDIO",
      // Pins 24-31 are the keyed section of the MicroMod connector.
      pin32: "PWM0",
      pin33: "GND",
      pin34: "A0",
      pin35: "USBHOST_D_P",
      pin36: "GND",
      pin37: "USBHOST_D_N",
      pin38: "A1",
      pin39: "GND",
      pin40: "G0_BUS0",
      pin41: "CAN_RX",
      pin42: "G1_BUS1",
      pin43: "CAN_TX",
      pin44: "G2_BUS2",
      pin45: "GND",
      pin46: "G3_BUS3",
      pin47: "PWM1",
      pin48: "G4_BUS4",
      pin49: "BATT_VIN_DIV3",
      pin50: "AUD_BCLK_PCM_CLK_I2S_SCK_PDM_CLK",
      pin51: "I2C_SDA1",
      pin52: "AUD_LRCLK_PCM_SYNC_I2S_WS_PDM_DATA",
      pin53: "I2C_SCL1",
      pin54: "AUD_IN_PCM_IN_I2S_IN_CAM_PCLK",
      pin55: "SPI_CS_N",
      pin56: "AUD_OUT_PCM_OUT_I2S_OUT_CAM_MCLK",
      pin57: "SPI_SCK",
      pin58: "AUD_MCLK",
      pin59: "SPI_COPI",
      pin60: "SPI_SCK1_SDIO_CLK",
      pin61: "SPI_CIPO",
      pin62: "SPI_COPI1_SDIO_CMD",
      pin63: "G10_ADC_D_P_CAM_VSYNC",
      pin64: "SPI_CIPO1_SDIO_DATA0",
      pin65: "G9_ADC_D_N_CAM_HSYNC",
      pin66: "SDIO_DATA1",
      pin67: "G8",
      pin68: "SDIO_DATA2",
      pin69: "G7_BUS7",
      pin70: "SPI_CS1_N_SDIO_DATA3",
      pin71: "G6_BUS6",
      pin72: "RTC_3V_BATT",
      pin73: "G5_BUS5",
      pin74: "V3_3",
      pin75: "GND",
    }}
  />
)

Keep this wrapper next to the footprint import in your carrier-board project. If your footprint uses different pad names, update the pinLabels keys to match its pad hints before routing.

Carrier-board example

This example connects a simple I2C expansion header to the primary MicroMod I2C bus and adds the carrier-side pull-ups described in the SparkFun interface documentation.

import microModM2Footprint from "./SparkFun_MicroMod_M2.kicad_mod"

export default () => (
  <board width="60mm" height="45mm">
    <MicroModConnector name="J1" footprint={microModM2Footprint} />

    <pinheader
      name="J_I2C"
      pinCount={4}
      pinLabels={{ pin1: "GND", pin2: "V3_3", pin3: "SDA", pin4: "SCL" }}
    />
    <resistor name="R_SDA" resistance="4.7kohm" footprint="0603" />
    <resistor name="R_SCL" resistance="4.7kohm" footprint="0603" />
    <capacitor name="C_DEC" capacitance="10uF" footprint="0805" />

    <trace from=".J1 > .GND" to=".J_I2C > .GND" />
    <trace from=".J1 > .V3_3" to=".J_I2C > .V3_3" />
    <trace from=".J1 > .I2C_SDA" to=".J_I2C > .SDA" />
    <trace from=".J1 > .I2C_SCL" to=".J_I2C > .SCL" />

    <trace from=".J1 > .V3_3" to=".R_SDA > .pin1" />
    <trace from=".R_SDA > .pin2" to=".J1 > .I2C_SDA" />
    <trace from=".J1 > .V3_3" to=".R_SCL > .pin1" />
    <trace from=".R_SCL > .pin2" to=".J1 > .I2C_SCL" />

    <trace from=".J1 > .V3_3" to=".C_DEC > .pin1" />
    <trace from=".J1 > .GND" to=".C_DEC > .pin2" />
  </board>
)

Signal groups to check

Group	Pins	Notes
Power	V3_3, GND, USB_VIN, V3_3_EN, RTC_3V_BATT, BATT_VIN_DIV3	MicroMod logic is 3.3 V. Do not expose 3.3 V pins to 5 V.
USB	USB_D_P, USB_D_N, USBHOST_D_P, USBHOST_D_N	Route USB pairs together, keep them short, and avoid stubs.
I2C	I2C_SDA, I2C_SCL, I2C_INT_N, I2C_SDA1, I2C_SCL1	I2C is open drain; place pull-ups on the carrier when the attached boards do not already provide them.
SPI and SDIO	SPI_COPI, SPI_CIPO, SPI_SCK, SPI_CS_N, secondary SPI_*1 and SDIO_* pins	Check whether the processor board exposes these as SPI, SDIO, or GPIO.
UART	UART_TX1, UART_RX1, UART_RTS1, UART_CTS1, UART_TX2, UART_RX2	UART1 and UART2 are intended to be free of USB-to-serial circuitry.
CAN	CAN_RX, CAN_TX	Add the transceiver and termination required by your carrier-board design.
Audio and camera	AUD_*, PCM_*, I2S_*, PDM_*, CAM_* aliases	These pins are shared by function; pick names that match the processor board mode you are using.
Debug and control	RESET_N, BOOT, SWDIO, SWDCK, G11_SWD_SWO	Reset and boot are open-drain control pins in the SparkFun descriptions.
General purpose	A0, A1, PWM0, PWM1, D0, D1_CAM_TRIG, G0_BUS0 through G10_ADC_D_P_CAM_VSYNC	Do not assume every processor board supports every alternate function.

Layout checklist

• Place and lock the M.2 connector before routing nearby circuits.
• Confirm the keyed section and insertion direction against the processor board.
• Keep connector keepouts, board-edge clearance, and mounting hardware clear.
• Route USB as a differential pair and keep it away from switching supplies.
• Put I2C pull-ups on one side of the bus only.
• Add test points for V3_3, GND, RESET_N, and the buses you expect to debug.
• Review processor-board current limits before powering displays, radios, motors, or sensor stacks from MicroMod power pins.