Shop OBEX P1 Docs P2 Docs Learn Events
MAX233 troubles — Parallax Forums

MAX233 troubles

ArchiverArchiver Posts: 46,084
edited 2002-10-06 15:20 in General Discussion
Hi everyone! I am working on a Basic Stamp 2 OEM project using the
Maxim MAX233 IC. I need to use the MAX233 to make the Basic Stamp's
connection to the computer more reliable. I built the MAX233 portion
according to the Maxim supplied datasheet, and with the help of a
Basic Stamp book. Unfortunately, the circuit only produces a garbled
output when fed through the Maxim IC. I am using the built-in DB9
port on the Basic Stamp 2 OEM. When the output of the Basic Stamp is
fed directly through the DB9 port to the computer, the serial output
is clear and appears correctly in the Basic Stamp terminal. I have
checked the circuit connections many times, and the baud settings in
the editor are correct. Do you have any suggestions on what might be
wrong? Thanks.
Jacob

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2002-10-06 04:59
    RS232 is negative logic. :-)

    In other words, -12V = logic 1 and +12V = Logic 0.


    --
    http://www.lennard.net.nz/
    Ben Lennard, NCEE, Dip EE

    Electronics R&D

    Hm: +64 4 972 7567
    Mb: +64 21 536 627
    87 Spencer Street
    Crofton Downs
    Wellington
    New Zealand

    "To the optimist, the glass is half full. To the pessimist, the glass is
    half empty. To the engineer, the glass is twice as big as it needs to be."

    No animals were harmed in the transmission of this email, although the
    Dog next door is living on borrowed time, let me tell you! Those of you
    with an overwhelming fear of the unknown will be gratified to learn that
    there is no hidden message revealed by reading this warning backwards.




    > From: "jacobhpower" <jacobhpower@m...>
    > Reply-To: basicstamps@yahoogroups.com
    > Date: Sun, 06 Oct 2002 02:10:27 -0000
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] MAX233 troubles
    >
    > Hi everyone! I am working on a Basic Stamp 2 OEM project using the
    > Maxim MAX233 IC. I need to use the MAX233 to make the Basic Stamp's
    > connection to the computer more reliable. I built the MAX233 portion
    > according to the Maxim supplied datasheet, and with the help of a
    > Basic Stamp book. Unfortunately, the circuit only produces a garbled
    > output when fed through the Maxim IC. I am using the built-in DB9
    > port on the Basic Stamp 2 OEM. When the output of the Basic Stamp is
    > fed directly through the DB9 port to the computer, the serial output
    > is clear and appears correctly in the Basic Stamp terminal. I have
    > checked the circuit connections many times, and the baud settings in
    > the editor are correct. Do you have any suggestions on what might be
    > wrong? Thanks.
    > Jacob
    >
    >
    > 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.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2002-10-06 15:20
    Thanks for the response! I changed my programming and now my project is
    working again.
    Jacob

    Original Message
    Wrom: MHV
    Sent: Saturday, October 05, 2002 9:14 PM
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] MAX233 troubles

    RS232 is negative logic. :-)

    In other words, -12V = logic 1 and +12V = Logic 0.


    --
    http://www.lennard.net.nz/
    Ben Lennard, NCEE, Dip EE

    Electronics R&D

    Hm: +64 4 972 7567
    Mb: +64 21 536 627
    87 Spencer Street
    Crofton Downs
    Wellington
    New Zealand

    "To the optimist, the glass is half full. To the pessimist, the glass is
    half empty. To the engineer, the glass is twice as big as it needs to be."

    No animals were harmed in the transmission of this email, although the
    Dog next door is living on borrowed time, let me tell you! Those of you
    with an overwhelming fear of the unknown will be gratified to learn that
    there is no hidden message revealed by reading this warning backwards.




    > Wrom: IBGDADRZFSQHYUCDDJBLVLMHAALPTCXLYRW
    > Reply-To: basicstamps@yahoogroups.com
    > Date: Sun, 06 Oct 2002 02:10:27 -0000
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] MAX233 troubles
    >
    > Hi everyone! I am working on a Basic Stamp 2 OEM project using the
    > Maxim MAX233 IC. I need to use the MAX233 to make the Basic Stamp's
    > connection to the computer more reliable. I built the MAX233 portion
    > according to the Maxim supplied datasheet, and with the help of a
    > Basic Stamp book. Unfortunately, the circuit only produces a garbled
    > output when fed through the Maxim IC. I am using the built-in DB9
    > port on the Basic Stamp 2 OEM. When the output of the Basic Stamp is
    > fed directly through the DB9 port to the computer, the serial output
    > is clear and appears correctly in the Basic Stamp terminal. I have
    > checked the circuit connections many times, and the baud settings in
    > the editor are correct. Do you have any suggestions on what might be
    > wrong? Thanks.
    > Jacob
    >
    >
    > 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.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >


    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.


    Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Get
    more from the Web. FREE MSN Explorer download : http://explorer.msn.com


    [noparse][[/noparse]Non-text portions of this message have been removed]
Sign In or Register to comment.