Shop OBEX P1 Docs P2 Docs Learn Events
sync-pulse? — Parallax Forums

sync-pulse?

damiondamion Posts: 39
edited 2006-06-28 19:16 in General Discussion
I'm a little confused as to what format to use for a sync-pulse.·When looking around the forums I see things like 1.5ms and I'm not entirely sure what that means. I understand that·it is a pulse which last for 1.5 micro seconds, but does that mean I should use the pulse out command·for the desired duration or what?·I guess·my question is:·are sync-pulses necessary and can anything be a sync-pulse for example·a character like "C".
thanks d

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-06-27 19:40
    A sync-pulse for what?· 1.5ms is actually a servos center position and translates to 1.5 milliseconds.· 1.5 microseconds would be 1.5us.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • damiondamion Posts: 39
    edited 2006-06-27 19:48
    Oh right okay. It's for a transmitter and reciever. From what I understand the reciever waits for a sync-pulse before logging on to the transmit session. But I don't really understand how to format it.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-06-27 19:59
    Which transmitter & receiver?· Is there a datasheet or specs so we can see what sync-pulse is required for the device?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • damiondamion Posts: 39
    edited 2006-06-27 20:06
    It is the ac4790-1000 from aerocomm here is the link

    http://www.aerocomm.com/rf_transceiver_modules/ac4790_mesh-ready_transceiver.htm
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2006-06-28 10:06
    damion -

    The best sync characters have both on and off (1 and 0) alternating bits within, to both turn on and off the data slicer. One often used character is x'55'. In binary X'55' looks like this:

    0101 0101

    So as you can see, the data slicer will be "warmed up" by such a configuration. Another often used character is X'AA' which looks like this in binary:

    1010 1010

    I suspect you get the idea from here.

    Regards,

    Bruce Bates

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    <!--StartFragment -->

    Post Edited (Bruce Bates) : 6/28/2006 10:14:18 AM GMT
  • damiondamion Posts: 39
    edited 2006-06-28 19:16
    Chris, Bruce

    Thanks for the information.

    In section 2.1.1.1 of the ac4790 users manual it says that the transciever initiates a session with other radios by transmitting a 25ms sync pulse. How do I determine such a pulse? Are either of the above mentioned configurations sufficient? Should format them in binary or ascii.

    Thanks again,
    d
Sign In or Register to comment.