November 18, 2016

Intel Galileo - Gen 2 - description of LED's

There are seven LED's (two are on the network connector for speed and link status). The five on the board are labelled, two on the left of the host USB and three to the right.
  • led "OC" (overcurrent on USB)
  • led "USB"
  • led "L" (user controlled on pin "13")
  • led "ON"
  • led "SD" The OC light has confusing descriptions. It used to indicate overcurrent when the board was being powered by USB, but you simply can't power the board via USB with a Gen 2 unit. I cannot believe you ever could (how could this run from 500 mA of 5 volts?) People see this light come on when the board is bricked or damaged. I don't see this LED on the schematic, so who knows. Page 27 of the schematic shows the power from USB components all crossed out (including a red LED), but if so and this LED is installed, how and why does it come on when the board is bricked? A clear case of bad documentation. This is LED "DS1" and indeed it is red.

    The USB light indicates that the micro USB client port is "ready to go". You are cautioned not to plug anything into this port unless the light is on. All of this seems sketchy.

    The "L" light is controlled by arduino signal 13. This is driven by GPIO 7 on Gen 2 boards and by GPIO 39 on Gen 1 boards. Yep, the hardware behind the arduino signals changes radically from Gen 1 to Gen 2. Some discussions label this light as "loading". Maybe it is used that way by the arduino support software, who knows.

    The "ON" light is driven by a power control signal that comes from the Quark.

    The "SD" light indicates SD card activity (I confirmed this by experiment).

    Feedback? Questions? Drop me a line!

    Tom's Computer Info / tom@mmto.org