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serial communication with 2p40 — Parallax Forums

serial communication with 2p40

ArchiverArchiver Posts: 46,084
edited 2004-05-19 17:24 in General Discussion
Hi,
Can anyone get the 2p40 serin and serout commands to work with baud
rates greater then 9600?

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-05-19 06:40
    Green,

    I asked this qustion a few days ago and got no answer. I can get two 2p's to
    talk at 115200 right next to each other, with no formatters, etc. I am going
    to try it at higher bauds via a bluetooth module, so I'll let you know how
    that goes.

    Jonathan

    www.madlabs.info


    Original Message
    From: "Green One" <greenish_green@y...>
    To: <basicstamps@yahoogroups.com>
    Sent: Tuesday, May 18, 2004 1:32 PM
    Subject: [noparse][[/noparse]basicstamps] serial communication with 2p40


    > Hi,
    > Can anyone get the 2p40 serin and serout commands to work with baud
    > rates greater then 9600?
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2004-05-19 14:07
    I do routinely. There are no problems with BS2p baud rate generation.
    Perhaps you're selecting the wrong parameters in your programs. A few
    weeks back I uploaded a template file that includes the proper baud
    settings for all BASIC Stamp modules up to 38.4K.

    Look for the file: PBASIC_Programming_Template.BS2

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: Green One [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=mVImT7TZ-vUDWAU9Mwmo1MVHlnau7S2j-ZrYLid47nWquX5svfCYs7RtgfFaNgyvCGW2g5JPwhcCndm9kf8]greenish_green@y...[/url
    Sent: Tuesday, May 18, 2004 3:33 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] serial communication with 2p40


    Hi,
    Can anyone get the 2p40 serin and serout commands to work with baud
    rates greater then 9600?
  • ArchiverArchiver Posts: 46,084
    edited 2004-05-19 14:09
    115.2K is really pushing it and conditions need to be perfect. If
    you're using the BS2p you should have no trouble with 56K, and I used
    38.4K all the time.

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: Jonathan Peakall [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=WXmfTZrYTvXAk9ZJJ5sgVgvo1kylLlEilQIzOsuF-EOjjTz-FC9_yLrKE3Me8lABUGxgejZYOPqMvA]jpeakall@p...[/url
    Sent: Wednesday, May 19, 2004 12:40 AM
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] serial communication with 2p40


    Green,

    I asked this qustion a few days ago and got no answer. I can get two
    2p's to talk at 115200 right next to each other, with no formatters,
    etc. I am going to try it at higher bauds via a bluetooth module, so
    I'll let you know how that goes.

    Jonathan

    www.madlabs.info


    Original Message
    From: "Green One" <greenish_green@y...>
    To: <basicstamps@yahoogroups.com>
    Sent: Tuesday, May 18, 2004 1:32 PM
    Subject: [noparse][[/noparse]basicstamps] serial communication with 2p40


    > Hi,
    > Can anyone get the 2p40 serin and serout commands to work with baud
    > rates greater then 9600?
  • ArchiverArchiver Posts: 46,084
    edited 2004-05-19 15:08
    The RS-232 'standard' was designed in an earlier
    age, when 19,200 baud was the most anyone needed.

    The 'higher' baud rates (like 115,200) push the
    limits of some MAX232 type drivers -- the MAXIM
    IC does not work well at that rate. This also
    pushes the limits of the cableing -- long
    cable runs (longer than 10 feet or so) don't
    work very well. (Note you CAN use RS485 drivers
    at these rates, which should be good to 4000
    feet at 115,200 baud)

    (What happens to the 232 signal
    is that the capacitance of the
    long cable filters the high frequency
    components out. This makes your nice
    115,200 baud square wave look like
    a more pure sine wave at the reciever
    -- and some single bits become little
    'bumps' in the signal, and never rise
    high enough to be recognized by the reciever).

    If you don't use a driver, then there is a
    definite limit to how far apart the two BS2
    modules can be, and what kind of
    cable you use to connect them. On the same
    board shouldn't be a problem, though.

    --- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
    wrote:
    > I do routinely. There are no problems with BS2p baud rate
    generation.
    > Perhaps you're selecting the wrong parameters in your programs. A
    few
    > weeks back I uploaded a template file that includes the proper baud
    > settings for all BASIC Stamp modules up to 38.4K.
    >
    > Look for the file: PBASIC_Programming_Template.BS2
    >
    > -- Jon Williams
    > -- Applications Engineer, Parallax
    > -- Dallas Office
    >
    >
    >
    Original Message
    > From: Green One [noparse][[/noparse]mailto:greenish_green@y...]
    > Sent: Tuesday, May 18, 2004 3:33 PM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] serial communication with 2p40
    >
    >
    > Hi,
    > Can anyone get the 2p40 serin and serout commands to work with
    baud
    > rates greater then 9600?
  • ArchiverArchiver Posts: 46,084
    edited 2004-05-19 17:24
    Jon, Allan,

    Thanks, that's what I needed to know. Now if I could just get the EB500
    changing baud rates, I'll be able to see how fast I can go. One nice thing
    about the EB500s is that the serial lines are very short, no cable to speak
    of, and then the EB500 deals with error checking. So hopefully I can push
    it...

    Jonathan

    www.madlabs.info



    Original Message
    From: "Allan Lane" <allan.lane@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Wednesday, May 19, 2004 7:08 AM
    Subject: [noparse][[/noparse]basicstamps] Re: serial communication with 2p40


    > The RS-232 'standard' was designed in an earlier
    > age, when 19,200 baud was the most anyone needed.
    >
    > The 'higher' baud rates (like 115,200) push the
    > limits of some MAX232 type drivers -- the MAXIM
    > IC does not work well at that rate. This also
    > pushes the limits of the cableing -- long
    > cable runs (longer than 10 feet or so) don't
    > work very well. (Note you CAN use RS485 drivers
    > at these rates, which should be good to 4000
    > feet at 115,200 baud)
    >
    > (What happens to the 232 signal
    > is that the capacitance of the
    > long cable filters the high frequency
    > components out. This makes your nice
    > 115,200 baud square wave look like
    > a more pure sine wave at the reciever
    > -- and some single bits become little
    > 'bumps' in the signal, and never rise
    > high enough to be recognized by the reciever).
    >
    > If you don't use a driver, then there is a
    > definite limit to how far apart the two BS2
    > modules can be, and what kind of
    > cable you use to connect them. On the same
    > board shouldn't be a problem, though.
    >
    > --- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
    > wrote:
    > > I do routinely. There are no problems with BS2p baud rate
    > generation.
    > > Perhaps you're selecting the wrong parameters in your programs. A
    > few
    > > weeks back I uploaded a template file that includes the proper baud
    > > settings for all BASIC Stamp modules up to 38.4K.
    > >
    > > Look for the file: PBASIC_Programming_Template.BS2
    > >
    > > -- Jon Williams
    > > -- Applications Engineer, Parallax
    > > -- Dallas Office
    > >
    > >
    > >
    Original Message
    > > From: Green One [noparse][[/noparse]mailto:greenish_green@y...]
    > > Sent: Tuesday, May 18, 2004 3:33 PM
    > > To: basicstamps@yahoogroups.com
    > > Subject: [noparse][[/noparse]basicstamps] serial communication with 2p40
    > >
    > >
    > > Hi,
    > > Can anyone get the 2p40 serin and serout commands to work with
    > baud
    > > rates greater then 9600?
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
    >
    >
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