Latency Timer, Windows control panel setting

wjcroftwjcroft Mount Shasta, CA
edited November 2014 in Software
The VCP, Virtual COM Port driver from FTDI has a Latency Timer that can be manually adjusted.  Using the default settings supplied with the driver (16 ms) appears to result in larger buffering delays for samples incoming from the OpenBCI dongle bluetooth link.  To adjust it, use your Control Panel as follows:

In Control Panel / Device Manager / Ports / USB Serial Port (your COM port for the dongle) / Port Settings / Advanced -- (whew!), is a setting called "Latency Timer" in milliseconds.  This is an FTDI specific item that controls how responsive the link is.  The default is 16 ms.  After changing this to 1 ms, the buffering pauses should improve substantially.  We don't believe there is any noticeable CPU penalty for this change, since the amount of data is small.

William

Comments

  • ThomasThomas France
    Quick note for linux users: this can be done by editing the /sys/bus/usb-serial/devices/ttyUSB0/latency_timer file.

    Bests regards

    Thomas
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