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Serial Loopback differences

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  • Serial Loopback differences

    I just noticed some odd things when trying to do loopback operation on some serial ports.

    I have setup both COM1 and COM2 to loopback at 115K. When I use BIT 5.3Pro it shows the throughput as 5340.7 Bytes/sec.

    I was tipped off by this while working with a vendor of ours and they were using Version 4.0 Pro. This version, when testing at 115K shows a throughput of 11359.7 Bytes/sec.

    Has something drastically changed with the translation of the throughput? Any insight?

  • #2
    It might be becuase you have selected a lower duty cycle on the serial test? Or becuase you have other tests running at the same time using up the CPU time?


    • #3
      I don't think this is the case. I am using a 100% idential machine, ONLY difference is the version of BIT (V4.0 compared to V5.3).

      The cycle is at 100%, and NO other tests are running.


      • #4
        Maybe it is the flow control setting in the preferences window?


        • #5
          Serial loopback speed differences

          I just started looking at the serial loopback test and see the same or similar issue (currently running B.I.T. 5.1):

          When testing one serial port, throughput seems to match the test speed (considering estimate of 10bits/byte-sent).

          However, when I select both serial ports for test in the preferences, the throughput for each port drops to about 1/2 the expected throughput, regardless of the test speed selected or test duty-cycle.

          What's the deal? - I know there is more than enough processor and bus bandwidth available to keep both UARTs operating at max throughput.

          So, where is the bottle-neck that's affecting the B.I.T. throughput results?


          • #6
            We will do some testing and post our results when available.