Skip to content

Add MicroMod carrier board tutorial #623

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
kebanks2 wants to merge 2 commits into
base: main
Choose a base branch
from
+331 −0
Open

Add MicroMod carrier board tutorial #623

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
a799e7a
Add tutorial for building a MicroMod carrier board
kebanks2 May 20, 2026
426a551
Add MicroMod graphical datasheet reference
kebanks2 May 21, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
331 changes: 331 additions & 0 deletions docs/tutorials/building-a-micromod-carrier-board.mdx
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,331 @@
---
title: Building a MicroMod Carrier Board
description: Learn how to model a SparkFun MicroMod-style carrier board with an M.2 connector, shared power rails, I2C pull-ups, and common breakout headers.
---

import CircuitPreview from "@site/src/components/CircuitPreview"

## Overview

SparkFun MicroMod processor boards use a 75-pin M.2 edge connector so that the
processor module can plug into different carrier boards. A carrier board usually
provides the regulated 3.3 V rail, ground return, reset and boot controls, and
breakouts for buses such as I2C, SPI, UART, SWD, PWM, and analog inputs.

This tutorial shows a reusable tscircuit pattern for documenting a MicroMod
carrier schematic. It intentionally focuses on the connector and signal mapping;
before fabricating a real board, confirm the exact connector footprint, keepout,
and mechanical dimensions against the MicroMod processor board and connector
datasheets.

## Start with the MicroMod M.2 socket

Use `<connector />` with `standard="m2"` and add explicit labels for the pins
you plan to route. The example below labels the most common carrier-board
signals from the MicroMod v1.0 pinout and leaves unused keyed or secondary
signals unconnected.

<CircuitPreview
splitView={false}
hidePCBTab
hide3DTab
defaultView="schematic"
code={`
const microModPinLabels = {
pin1: "GND",
pin2: "V3_3",
pin3: "USB_D_P",
pin4: "USB_D_N",
pin6: "RESET",
pin9: "USB_VIN",
pin11: "BOOT",
pin12: "I2C_SDA",
pin14: "I2C_SCL",
pin16: "I2C_INT",
pin17: "UART_TX1",
pin19: "UART_RX1",
pin21: "SWDCK",
pin23: "SWDIO",
pin32: "PWM0",
pin34: "A0",
pin38: "A1",
pin41: "CAN_RX",
pin43: "CAN_TX",
pin55: "SPI_CS",
pin57: "SPI_SCK",
pin59: "SPI_COPI",
pin61: "SPI_CIPO",
pin74: "V3_3",
pin75: "GND",
}

export default () => (
<board width="60mm" height="36mm">
<connector
name="J_MICROMOD"
standard="m2"
pinLabels={microModPinLabels}
schWidth="28mm"
schHeight="46mm"
connections={{
pin1: "net.GND",
pin2: "net.V3_3",
pin6: "net.RESET",
pin11: "net.BOOT",
pin12: "net.I2C_SDA",
pin14: "net.I2C_SCL",
pin17: "net.UART_TX",
pin19: "net.UART_RX",
pin21: "net.SWDCK",
pin23: "net.SWDIO",
pin32: "net.PWM0",
pin34: "net.A0",
pin38: "net.A1",
pin55: "net.SPI_CS",
pin57: "net.SPI_SCK",
pin59: "net.SPI_COPI",
pin61: "net.SPI_CIPO",
pin74: "net.V3_3",
pin75: "net.GND",
}}
pcbX={0}
pcbY={0}
/>
</board>
)
`}
/>

## Add carrier-board power

MicroMod signals are 3.3 V compatible. Do not connect processor GPIO or bus
signals directly to 5 V logic. The carrier board should provide a clean 3.3 V
rail, local bulk capacitance, and small decoupling capacitors close to the
connector power pins. If your carrier accepts USB or battery input, model that
power path separately and feed the connector from the regulated rail.

<CircuitPreview
splitView={false}
hidePCBTab
hide3DTab
defaultView="schematic"
code={`
const microModPinLabels = {
pin1: "GND",
pin2: "V3_3",
pin6: "RESET",
pin11: "BOOT",
pin12: "I2C_SDA",
pin14: "I2C_SCL",
pin74: "V3_3",
pin75: "GND",
}

export default () => (
<board width="64mm" height="42mm">
<net name="V3_3" isForPower />
<net name="GND" isGround />

<connector
name="J_MICROMOD"
standard="m2"
pinLabels={microModPinLabels}
connections={{
pin1: "net.GND",
pin2: "net.V3_3",
pin6: "net.RESET",
pin11: "net.BOOT",
pin12: "net.I2C_SDA",
pin14: "net.I2C_SCL",
pin74: "net.V3_3",
pin75: "net.GND",
}}
schWidth="24mm"
schHeight="26mm"
/>

<capacitor
name="C_BULK"
capacitance="10uF"
footprint="0805"
connections={{ pos: "net.V3_3", neg: "net.GND" }}
/>
<capacitor
name="C_DEC1"
capacitance="100nF"
footprint="0402"
connections={{ pos: "net.V3_3", neg: "net.GND" }}
/>
</board>
)
`}
/>

## Break out common buses

Carrier boards usually expose a small set of MicroMod signals rather than every
pin. I2C is a good default because MicroMod defines `I2C_SDA` and `I2C_SCL` as
open-drain signals that need pull-up resistors on the carrier board. UART, SPI,
SWD, reset, and boot are common debugging and expansion connections.

<CircuitPreview
splitView={false}
hidePCBTab
hide3DTab
defaultView="schematic"
code={`
const microModPinLabels = {
pin1: "GND",
pin2: "V3_3",
pin6: "RESET",
pin11: "BOOT",
pin12: "I2C_SDA",
pin14: "I2C_SCL",
pin17: "UART_TX1",
pin19: "UART_RX1",
pin21: "SWDCK",
pin23: "SWDIO",
pin55: "SPI_CS",
pin57: "SPI_SCK",
pin59: "SPI_COPI",
pin61: "SPI_CIPO",
pin74: "V3_3",
pin75: "GND",
}

export default () => (
<board width="78mm" height="54mm">
<net name="V3_3" isForPower />
<net name="GND" isGround />

<connector
name="J_MICROMOD"
standard="m2"
pinLabels={microModPinLabels}
schWidth="26mm"
schHeight="40mm"
connections={{
pin1: "net.GND",
pin2: "net.V3_3",
pin6: "net.RESET",
pin11: "net.BOOT",
pin12: "net.I2C_SDA",
pin14: "net.I2C_SCL",
pin17: "net.UART_TX",
pin19: "net.UART_RX",
pin21: "net.SWDCK",
pin23: "net.SWDIO",
pin55: "net.SPI_CS",
pin57: "net.SPI_SCK",
pin59: "net.SPI_COPI",
pin61: "net.SPI_CIPO",
pin74: "net.V3_3",
pin75: "net.GND",
}}
/>

<pinheader
name="J_I2C"
pinCount={4}
gender="female"
pitch="2.54mm"
pinLabels={["GND", "3V3", "SDA", "SCL"]}
connections={{
pin1: "net.GND",
pin2: "net.V3_3",
pin3: "net.I2C_SDA",
pin4: "net.I2C_SCL",
}}
/>
<resistor
name="R_SDA"
resistance="4.7k"
footprint="0402"
connections={{ pin1: "net.V3_3", pin2: "net.I2C_SDA" }}
/>
<resistor
name="R_SCL"
resistance="4.7k"
footprint="0402"
connections={{ pin1: "net.V3_3", pin2: "net.I2C_SCL" }}
/>

<pinheader
name="J_UART"
pinCount={4}
gender="male"
pitch="2.54mm"
pinLabels={["GND", "3V3", "TX", "RX"]}
connections={{
pin1: "net.GND",
pin2: "net.V3_3",
pin3: "net.UART_TX",
pin4: "net.UART_RX",
}}
/>

<pinheader
name="J_SPI"
pinCount={6}
gender="male"
pitch="2.54mm"
pinLabels={["GND", "3V3", "CIPO", "COPI", "SCK", "CS"]}
connections={{
pin1: "net.GND",
pin2: "net.V3_3",
pin3: "net.SPI_CIPO",
pin4: "net.SPI_COPI",
pin5: "net.SPI_SCK",
pin6: "net.SPI_CS",
}}
/>

<pinheader
name="J_SWD"
pinCount={4}
gender="male"
pitch="2.54mm"
pinLabels={["GND", "3V3", "SWDIO", "SWDCK"]}
connections={{
pin1: "net.GND",
pin2: "net.V3_3",
pin3: "net.SWDIO",
pin4: "net.SWDCK",
}}
/>

<pushbutton
name="SW_RESET"
connections={{ pin1: "net.RESET", pin2: "net.GND" }}
/>
<pushbutton
name="SW_BOOT"
connections={{ pin1: "net.BOOT", pin2: "net.GND" }}
/>
</board>
)
`}
/>

## Layout checklist

- Use the MicroMod connector drawing for pad geometry, key position, insertion
direction, and board-edge keepout.
- Keep local 100 nF decoupling close to the 3.3 V and ground connector pins, and
add enough bulk capacitance for the processor board and any carrier peripherals.
- Treat all exposed bus pins as 3.3 V logic unless a processor-board datasheet
explicitly says otherwise.
- Put I2C pull-ups on the carrier board. Start with 4.7 kOhm for short traces
and adjust for bus capacitance and target speed.
- Route USB and high-speed interfaces as controlled, short, matched differential
paths when you use them.
- Mark intentionally unused MicroMod pins as no-connects in your design notes so
future carrier-board revisions do not route them by accident.

## References

- [SparkFun MicroMod Interface pin descriptions](https://cdn.sparkfun.com/assets/learn_tutorials/1/2/0/6/SparkFun_MicroMod_Interface_v1.0_-_Pin_Descriptions.pdf)
- [SparkFun MicroMod Interface pinout](https://cdn.sparkfun.com/assets/learn_tutorials/1/2/0/6/SparkFun_MicroMod_Interface_v1.0_-_Pinout.pdf)
- [SparkFun MicroMod General Pinout graphical datasheet](https://cdn.sparkfun.com/assets/learn_tutorials/1/1/8/9/MicroMod_General_Pinout_v10_Graphical_Datasheet.pdf)
- [SparkFun Getting Started with MicroMod](https://learn.sparkfun.com/tutorials/getting-started-with-micromod)
- [SparkFun MicroMod product page](https://www.sparkfun.com/micromod)
Loading