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SOMO-II serial command delay

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  • SOMO-II serial command delay


    Please could you add some timing constraints for SOMO-II serial commands to your datasheet, for example how long reset/play/volume/etc take to execute and how long to leave between serial commands.

    I've been experimenting with your module for sound effect playback in interactive exhibits my company produces. Looks good so far but I need to make sure its responsive enough.
    Am I correct in assuming SOMO-II doesn't buffer serial commands, so I should leave a bit of time between packets, say 25-50ms? I've tried profiling how long each operation takes by waiting for serial feedback (not always possible in some of our designs, which require banks of 8-16 players), but with rather variable results. If you have any guideline timings, it would be very much appreciated!

    Many thanks

  • #2
    Hi Guyg,

    Thank you for your suggestion, we will add that to our latest batch of datasheets.

    The SOMO-II does not buffer the commands but execute it as soon as it is receives (as long as the commands are correct)
    In our projects and applications we try to put 50-100ms delays to make sure that the SOMO-II receives the commands, but yes, the 25-50ms is possible.

    However, in my experience the SOMO-II reaction/execution time is very fast. Sometimes, the problem lies with the audio files, especially if the files has long intro music/silence. What I do is splice the audio file to the exact second that the file will play with voice/music. This way, the audio files are playing immediately when touched. Like the Drum Pad project we did:

    If you are familiar with our 4D Workshop IDE GUI objects, I've used a slider bar to change the volume of the SOMO-II while an audio is playing, the execution is pretty much fast and realtime even without pause/delay on the program.

    Again thank you for your suggestion, we review and work on this matter.


    • #3
      Thanks for your quick reply, Mark! The drum pad was a nice example.

      Would there be any chance of adding a small buffer (say 4+ packets long) in future revisions of the SOMO-II? I think it would make coding for it easier, as one could just send a few instructions in immediate succession (such as Stop playback, Change Volume, Play a new track) without needing to wait a bit between. The commands would still be parsed and acted upon one at a time, so replies would come back from the module with some delay between, I guess.



      • #4
        Good day Guyg,

        I think the addition of small buffer is not possible, as the chip controller is pre-programmed.
        Try enabling the FEEDBACK byte, and as soon as you received an acknowledgement from the SOMO-II, you can immediately send a new command.
        You can also try the attached software, This is a tester software we use for the SOMO-II. Enable the feedback mode
        and click on the commands to observe the time spent by the SOMO-II.

        Also if you are trying to capture and differentiate the Feedback replies, try capturing the Start byte or End byte to separate the incoming replies.

        I hope this helps,
        Attached Files