SparkFun MicroMod Main Board - Double

The MicroMod Main Board - Double is a specialized carrier board that allows you to interface a MicroMod Processor Board with up to two MicroMod Function Boards. With the M.2 MicroMod connector, connecting your Processor and Function Boards is a breeze. Simply match up the key on your board's beveled edge connector to the key on the M.2 connector and secure the boards with screws.

The Double Main Board includes one USB-C connector for power and programming the Processor Board. A jumper is available on the back of the board to isolate the USB C's shield pin. Two buttons for reset and boot are also populated on the board. Processor Board pins are also broken out as 2x5 SWD pins. Also, included on the board is a 2A resettable fuse and 3.3V/1A voltage regulator. A second 3.3V/500mA voltage regulator is included on the board to power your Qwiic-enabled devices. We've even added convenient PTH jumpers for advanced users looking to bypass the fuse and measure the current consumption on the 5V and 3.3V lines for low-power testing. For those that need to go remote with their application, the board includes a 2-pin JST connector and a single-cell LiPo MCP73831 charge IC (set to a charge rate of 500mA).

Two switches have been included to toggle between the general-purpose pins and each Function Board's voltage regulator. A third switch has also been included to switch between different SPI chip select pins on the second Function Board. Four status LEDs are available for power and charging. These can also be disabled through the jumpers. There is a microSD card socket so you can also plug in a microSD card for data logging. The microSD socket can be disabled through the I/O pins. Finally, two Qwiic connectors are populated on the board with built-in pull-up resistors to easily add Qwiic-enabled I2C devices to your projects!

Note: A MicroMod Processor and Function Boards are not included with the MicroMod Main Board. These boards will need to be purchased separately.

MicroMod is a modular interface ecosystem that connects a microcontroller “processor board” to various “carrier board” peripherals. Utilizing the M.2 standard, the MicroMod standard is designed to easily swap out processors and function boards on the fly. Pair a specialized carrier board for the project you need with your choice of compatible processor!

  • 1x MicroMod Main Board - Double
  • 4x Phillips #0 M2.5x3mm Screws
  • Input Voltage Range
    • 5V via USB C Connector
    • ~3.7V to 4.2V via LiPo Battery Connector
  • Built-in Resettable PTC Fuse (Rated 5V/2A)
  • AP7361C 3.3V Voltage Regulator (Rated 1A)
  • AP7347DQ 3.3V Voltage Regulator (Rated 500mA)
  • Integrated MCP73831 Single Cell LiPo Charge Circuit
    • 500mA
  • Ports
    • 1x USB Type C Connector
    • 1x 2-Pin JST Connector
    • M.2 Connectors
      • 1x MicroMod Processor Board
      • 2x MicroMod Function Boards
    • 2x Qwiic Enabled I2C
    • 1x MicroSD Card Socket
    • 1x SWD 2x5 Header
  • Built-in MUX for UART1
  • Buttons
    • 1x Reset
    • 1x Boot
  • 3x Switches
    • Function Board Zero Power Enable Pins
    • Function Board One Power Enable Pins
    • SPI1 Chip Select Alternative Pins
  • LEDs
    • 1x VIN
    • 1x 3.3V
    • 1x Qwiic 3.3V
    • 1x CHG
  • Plated Through Holes
    • RST
    • 5V (MEAS)
    • V_BATT
    • 3.3V (MEAS)
  • Jumpers
    • USB SHLD
    • 5V MEAS
    • 3.3V MEAS
    • PTC
    • 3.3V EN
    • VIN LED
    • 3.3V LED
    • Qwiic 3.3V LED
    • I2C
    • Battery Voltage Divider
  • Board Dimensions
    • 4.90" x 2.90"

SparkFun MicroMod Main Board - Double Product Help and Resources

MicroMod Main Board Hookup Guide V2

January 5, 2023

The MicroMod Main Board - Single and Double are specialized carrier boards that allow you to interface a Processor Board with a Function Board(s). The modular system allows you to add an additional feature(s) to a Processor Board with the help of a Function Board(s). In this tutorial, we will focus on the basic functionality of the Main Board - Single V2.1 and Main Board - Double and V2.2.

Cellular Function Board - Blues Wireless Notecarrier

January 5, 2023

Add a global cellular module to your MicroMod project with the SparkFun Cellular Function Board - Blues Wireless Notecarrier. With this Function board you can not only send data to and from your MicroMod project, you can even update the firmware on the STM32 MicroMod Processor.

Core Skill: DIY

Whether it's for assembling a kit, hacking an enclosure, or creating your own parts; the DIY skill is all about knowing how to use tools and the techniques associated with them.


Skill Level: Noob - Basic assembly is required. You may need to provide your own basic tools like a screwdriver, hammer or scissors. Power tools or custom parts are not required. Instructions will be included and easy to follow. Sewing may be required, but only with included patterns.
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Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

1 Programming

Skill Level: Noob - Programming will be limited to basic drag and drop interfaces like ModKit or Scratch. You won't be writing code, but you will still need to understand some basics of interfacing with hardware. If you?re just using a sensor, it's output is analog.
See all skill levels

Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

2 Electrical Prototyping

Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
See all skill levels


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Member #517719 / about 2 years ago / 1

    Curious to know the difference between the previous version and this? Is it just moving to switches instead of jumpers for the voltage regulators?

    • Member #517719 / about 2 years ago / 1

      Ah, never mind - just noticed an updated hookup guide:

      Revision Changes

      The following changes to the Main Board Single V2.1 and Main Board Double V2.2 include:

      Rotate silkscreen for the connectors and a majority of the labels. Add TVS diodes for ESD protection on the USB pins. Add SHLD jumper to isolate the USB Type C connector's shield pin. Add a 5V MEAS PTH jumper as a measurement for 5V. Remove the 500mA/100mA selector for the LiPo charge circuit. The board now charges at a default rate of 500mA only. Add a DIVIDER jumper to remove the resistor divider that is connected to processor's "BATT_VIN/3" pin for low power applications. Add a dedicated 3.3V/500mA voltage regulator for the Qwiic port. Add GPIO control of 3.3V voltage regulator (I2C_SCL1-Processor). Add a LED for the 3.3V Qwiic port with a QWIIC LED jumper to disable. Add a transistor to disable power to the microSD socket (can be controlled using I2C_SCL1-Processor). Add multiplexed primary UART pins to send serial data to Function Board(s). Add PTH pins for multiplexed UART (Main Board Single v2.1 only). Move PWR_EN0 from SDIO_Data2_Processor to PWM1 (Main Board - Single v2.1 only) Add two 2.2kΩ I2C pull-ups to the primary I2C pins with jumpers (I2C) to disable. Replace male header pins and 2-pin shunt with SMD switches to adjust the Function Board Power enable pins (Main Board - Double v2.2 only). Add option to adjust Function Board One's secondary SPI CS pin (i.e. "CS1-processor" and "A1-processor") with a SMD switch (Main Board - Double V2.2 only).

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