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QBasic Serial Com w/ Stamp — Parallax Forums

QBasic Serial Com w/ Stamp

ArchiverArchiver Posts: 46,084
edited 2003-08-01 16:10 in General Discussion
hey everyone,
I'm using qbasic to talk with my stamp via a serial connection.
One site which had example code for this type of application said
that one must put the following code in the qbasic code in order
to "clear the stamp's DTR bit":
tcmp = INP(&H3FC)
OUT &H3FC, tcmp AND 254

However, I have found that qbasic talks with the stamp just fine
without these two lines of code. In fact, when I use that code, the
stamp restarts everytime that code is executed. Without using the
code, I'm able to talk (using a qbasic program which acesses the
serial port) with the stamp without the stamp restarting all the
time. Does anybody know why clearing the dtr bit should be done, and
yet why it doesn't seem to be needed in my program? Thanks!

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-08-01 16:10
    I'm working from memory, but I believe the DTR pin on the serial port is
    used to reset the stamp prior to programming. It should be disconnected or
    off when you're using the programming port as a serial port. I hope I'm not
    misleading you...

    Ryan

    Original Message
    From: Sam [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=WiLAO0TWetAC9a9n3_VK6HH-rKX5Lm7aBUGG8gedZVpviquDe-dIY3WHvVjRQVNxgCIpHaEb7Puz]hard-on@t...[/url
    Sent: Friday, August 01, 2003 10:54 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] QBasic Serial Com w/ Stamp


    hey everyone,
    I'm using qbasic to talk with my stamp via a serial connection.
    One site which had example code for this type of application said
    that one must put the following code in the qbasic code in order
    to "clear the stamp's DTR bit":
    tcmp = INP(&H3FC)
    OUT &H3FC, tcmp AND 254

    However, I have found that qbasic talks with the stamp just fine
    without these two lines of code. In fact, when I use that code, the
    stamp restarts everytime that code is executed. Without using the
    code, I'm able to talk (using a qbasic program which acesses the
    serial port) with the stamp without the stamp restarting all the
    time. Does anybody know why clearing the dtr bit should be done, and
    yet why it doesn't seem to be needed in my program? Thanks!


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