3 Replies Latest reply on Mar 24, 2015 3:09 AM by dh29

    Intel i218-LM link speed LED states?

    dh29

      I am using the Intel i218-LM ethernet controller. 

       

      When I disconnect the ethernet cable the link speed LED pins for both LINK100# and LINK1000# go ACTIVE LOW.

       

      Why are the LED pins being driven ACTIVE LOW when a 100 or 1000 link cannot possibly exist as no cable is connected?  I would have expected the lines to be INACTIVE HIGH.

      Is this behavior normal for Intel controllers?

        • 1. Re: Intel i218-LM link speed LED states?
          wb_Intel

          Hi dh29,

            Thank you for the post, let me further check on this.

           

          rgds,

          wb

          • 2. Re: Intel i218-LM link speed LED states?
            wb_Intel

            Hi dh29,

             

                         Here is the datasheet you can refer to http://www.intel.es/content/dam/www/public/us/en/documents/datasheets/i218-ethernet-connection-datasheet.pdf about the LED. Based on the information therein, believe what you are experiencing is normal.  Since the controller does not complete shut down but it stays on ULP in order to detect incoming physical connection so the LED pins stays on active low

             

                          Hope this info helps.

             

            rgds,

            wb

            • 3. Re: Intel i218-LM link speed LED states?
              dh29

              Hi wb_Intel,

               

              Thanks you for your update.

               

              I had previously viewed the datasheet, and I agree that your description of the device staying in ULP when the cable is disconnected is correct.

               

              However, the fact that as you state "the controller does not complete shut down" surely implies that the device should still 'drive' the LEDs according to there definition.  The LED is defined as showing that a 100 Mbps or a 1000 Mbps link is present.  With no cable connected, there cannot possibly be a 100 Mbps or 1000 Mbps link present, and therefore the LED should NOT be active.

               

              In addition, it makes no sense that when a device enters a ULTRA LOW POWER state, for it then to drive lines ACTIVE, thereby consuming MORE power!

               

              I have marked you answer as the 'Correct Answer' as I believe your description to be correct, event though I believe Intel's design of the device to be flawed.

               

              Regards,

              dh29