Custom Expansion Board Tips for the Intel® Edison Platform





You can design a custom expansion board to use with the Intel® Edison platform. Here are some useful tips to consider when designing a custom expansion board.

The Hirose* 70-pin connector

The expansion board used for the Intel Edison platform should have a Hirose 70-pin DF40 Series receptacle connector. Different receptacle connectors mate with the Hirose header connector. The only difference between the different receptacle connectors is the stacking height, which is an important detail to consider when designing a custom expansion board. The Hirose 70-pin DF40 Series Datasheet document provides more detail about the Hirose 70-pin connector.

Voltage level I/O pins

All Intel Edison platforms have I/O pins that use 1.8V signaling (with exception of USB). This is an important detail for custom expansion board design, because a voltage shifter might be needed. Check the datasheet of the external device that you plan to use with your design.


The Intel Edison platform has a few pins that should be connected in every custom expansion board designed:

  • VSYS: Pins 2, 4, and 6 should be connected to the system input power, known as VSYS. The input voltage can be from 3.15V to 4.5V.

  • GND: Pins 1, 5, 9, 11, 13, and 15 are the ground pins, and as in every other expansion board, they are connected to the ground plane.

  • DCIN: Pin 14 is a power input pin, called DCIN. The DCIN should be connected to VSYS if the design is using a DC power adapter.

  • PWRBTN#: Pin 17 is the power/sleep button, known as PWRBTN#. This pin should be connected to a momentary push button.

    • Press and hold the power/sleep button to power down, leaving the I/O configuration in its current state.

    • Press the button momentarily to reboot, or to go in or out of sleep mode.

    • Pressing and holding the power button for more than 2 seconds but less than 7 seconds turns on the Access Point (AP) mode.

Below are other connections to consider depending on your custom expansion board design:

  • RESET_OUT#: Pin 36 is the system reset out, an open-drain output, and driven low by default out of system reset. This signal is used by external hardware to indicate a system reset. The I/O pins are undefined until RESET_OUT# transitions high.

  • RCVR_MODE and FW_RCVR: Pins 31 (RCVR_MODE) and 69 (FW_RCVR) are special pins used during boot to cause the SoC to force firmware and OS image download. They are used to provide a recovery mechanism in the event of a corrupted flash image. The FW_RCVR signal must be held low during boot until RESET_OUT# goes high. Both pins should be connected to momentary push buttons.

  • V_VBAT_BKUP: Pin 23 is an input pin, used to attach a backup battery for the RTC.

  • 1.8V and 3.3V: Pins 8, 10, and 12 are voltage output pins. They can be used for external hardware with low power consumption. Pin 12 is a 1.8V voltage output and pins 8 and 10 are a 3.3V voltage output.

  • MSIC_SLP_CLK and OSC_CLK_OUT_0: The Intel® Edison platform has two clock outputs. A 32-KHz sleep clock connected to pin 7 called MSIC_SLP_CLK, and a high frequency 19.2-MHz clock connected to pin 67 called OSC_CLK_OUT_0.

Antenna keep-out zone

Keep the area under and around the onboard chip antenna free of all components, routes, and ground planes.

Internal interfaces

There are several interfaces that can be used to communicate to secondary devices. These interfaces are:

  • Two I2C interfaces
  • One I2S interface
  • One SPI interface
  • One SD card interface
  • Two UART interfaces, one of them with flow control
  • Four PWM pins
  • One USB OTG interface

The Intel Edison platform has 9 general purpose input/output (GPIO) pins. If the interfaces listed here aren't being used, they can be turned into GPIOs.

The onboard chip antenna included in the Intel Edison compute module provides a wireless interface for connection to WiFi/BT networks.