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LEDs

Desktop Setup

Primary LED (Next to Button)​

The Primary LED displays top-level power status and system functionality. It indicates whether the board is connected, in power-off mode, updating, or experiencing an error.

Power States & Operating Mode​

LED StateMeaning
Off (blank)No power applied to the device (power-off mode).
Solid RedDevice has power, but the Linux CPU is completely powered off
Blinking YellowThe device is in a firmware or system update mode.
Blinking GreenBooting Linux → The OS is starting up.
Glowing GreenLinux booted → The OS is fully running.
Glowing MagentaConnected to the Particle Cloud through Wi-Fi → internet connection is working.
Glowing CyanConnected to the Particle Cloud through the cellular network → internet connection is working.
Blinking Red (Patterned)Device Crash / Malfunction → The device will automatically reboot after a period of time.

Activity LED (Near USB Ports)​

The Activity LED is wired directly to the Linux processor and is managed by the kernel's activity LED driver.

  • By default, it follows preconfigured system parameters chosen by Particle.
  • The behavior is user-configurable, allowing developers to override its default settings.

Activity LED States​

LED StateMeaning
OffLinux is not running (no system activity).
Mostly off, periodically blinking off at 2hzLinux is starting. The kernel is running but user space has yet to start
Mostly off, periodically blinking onLinux is operating Activity LED shows the activities in the system. Battery is not charging
Mostly on, periodically blinking offLinux is operating Activity LED shows the activities in the system. Battery is charging!

Customizable LED Behavior​

The Primary LED and Activity LED can be fully controlled from the Linux side.

  • Developers can override LED behavior to indicate:

    • Wi-Fi hotspot status
    • Custom application activity
    • Network connection events

🔧 Stay tuned for further documentation on customizing LED functionality in Tachyon.