Using SparkFun MicroMod M.2 Connectors
Overview
SparkFun MicroMod uses an M.2 connector so a processor board can plug into a
carrier board or a main board. In tscircuit, model the carrier-side connector
with <connector />, label the MicroMod pins you use, then connect those pins
to the carrier-board power, reset, boot, and peripheral circuits.
This tutorial focuses on the carrier-board side of the interface. It shows the common pins needed by many MicroMod designs:
- 3.3 V, USB input power, and ground
- 3.3 V regulator enable
- reset and boot controls
- USB data pins
- primary I2C, SPI, and UART buses
- a Qwiic-style I2C expansion header
Carrier Connector Example
Pin Groups to Bring Out
| Group | MicroMod pins in this example | Carrier-board responsibility |
|---|---|---|
| Power | 3V3, USB_VIN, GND, 3V3_EN | Provide the 3.3 V rail, USB input power, return path, and regulator enable behavior. |
| Reset and boot | RESET#, BOOT | Add user-accessible controls or test points; both are open-drain style control signals in SparkFun's interface guide. |
| USB | USB_D+, USB_D- | Route as a differential pair if the processor board exposes native USB through the connector. |
| I2C | I2C_SDA, I2C_SCL | Add carrier-side pullups and route to Qwiic, sensors, or other low-speed peripherals. |
| SPI | SPI_COPI, SPI_CIPO, SPI_SCK, SPI_CS# | Route to displays, memory, radios, or other SPI peripherals. |
| UART | UART_TX1, UART_RX1 | Route to serial expansion, debug headers, or carrier-board devices. |
Design Checklist
Before routing a MicroMod carrier board:
- keep all carrier-board signals at 3.3 V logic levels unless the processor board documentation says otherwise
- add I2C pullups on the carrier board when you expose the primary I2C bus
- keep reset and boot controls open-drain friendly so the processor board can still drive or pull those signals as intended
- decide whether
USB_D+andUSB_D-go to the connector, to a USB protection circuit, or remain unused for a processor board that does not need native USB - connect only the buses your carrier actually uses; unused MicroMod pins can be left unconnected
- verify the exact processor board before assigning optional pins such as ADC, PWM, camera, audio, SWD, CAN, or secondary SPI/SDIO