Shop OBEX P1 Docs P2 Docs Learn Events
7 Segment Displays — Parallax Forums

7 Segment Displays

ArchiverArchiver Posts: 46,084
edited 2003-01-24 23:37 in General Discussion
Hello Everyone [noparse]:)[/noparse]

I'm sorry but I'm being a extremely lazy here. I'm going to trawl for
ideas. Basically I want to build a slate with 10 seven segment displays (I
found some surplus ones at 10p (15c) each), However I would like to control
and program this display Via a basic stamp.

Each figure needs to be controlled individually and preferably serially does
anyone have an idea of a good driver to do this ?

Justin

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2001-09-06 14:40
    Hi Justin,

    Our synop board might provide the I/O pins you need.
    It provides 10 sections with 8 I/O each, enough to
    drive 10 7-segment (incl. decimal point) directly
    or 20 7-segment that are BCD controlled, or 80 modules
    that are serially controlled.
    Take a look http://www.boselectro.nl/synop.html
    Boards are still available for 30 US$ per board plus 5 US$ shipping.
    Note that serial drivers for individual I/O are yet to be written.
    Send me an email at peterverkaik@b...
    if it is what you are looking for.

    regards peter


    Oorspronkelijk bericht
    Van: Justin Pentecost [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Zrgrjhuqpvq0ZQbazboBsa25OwEP9wVZZBb-H15R2dzBeBk6FDyTR7SMAt9Ss4gJe91PPjep]justin@k...[/url
    Verzonden: donderdag 6 september 2001 14:14
    Aan: basicstamps@yahoogroups.com
    Onderwerp: [noparse][[/noparse]basicstamps] 7 Segment Displays


    Hello Everyone [noparse]:)[/noparse]

    I'm sorry but I'm being a extremely lazy here. I'm going to trawl for
    ideas. Basically I want to build a slate with 10 seven segment displays (I
    found some surplus ones at 10p (15c) each), However I would like to control
    and program this display Via a basic stamp.

    Each figure needs to be controlled individually and preferably serially does
    anyone have an idea of a good driver to do this ?

    Justin


    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 2001-09-06 14:55
    At 9/6/2001 Thursday 09:14 AM, Justin Pentecost promulgated:
    >Hello Everyone [noparse]:)[/noparse]
    >
    >I'm sorry but I'm being a extremely lazy here. I'm going to trawl for
    >ideas. Basically I want to build a slate with 10 seven segment displays (I
    >found some surplus ones at 10p (15c) each), However I would like to control
    >and program this display Via a basic stamp.
    >
    >Each figure needs to be controlled individually and preferably serially does
    >anyone have an idea of a good driver to do this ?
    >
    >Justin
    >
    >Justin -

    The MAX-7219 should do what you need to do:
    http://dbserv.maxim-ic.com/quick_view2.cfm?pdf_num=1339

    Free samples should be availble.

    Regards,

    Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2001-09-06 15:07
    You consider the Max7219? You can daisy-chain-ish 2 Max's together to
    support up to 16 digits. It only costs $20 per chip and uses the shiftout
    command on the basic stamp.

    Go all the way down to page 20-22:
    http://www.parallaxinc.com/downloads/Documentation/Application%20Kits/MAX721
    9%208-Digit%20LED%20Display%20Driver/MAX7219-21%208-Digit%20LED%20Display%20
    Driver.pdf

    Hope this helps.

    Chris Shuster
    http://www.cpuman.f2s.com/

    Original Message
    From: "Justin Pentecost" <justin@k...>
    To: <basicstamps@yahoogroups.com>
    Sent: Thursday, September 06, 2001 9:14 PM
    Subject: [noparse][[/noparse]basicstamps] 7 Segment Displays


    > Hello Everyone [noparse]:)[/noparse]
    >
    > I'm sorry but I'm being a extremely lazy here. I'm going to trawl for
    > ideas. Basically I want to build a slate with 10 seven segment displays
    (I
    > found some surplus ones at 10p (15c) each), However I would like to
    control
    > and program this display Via a basic stamp.
    >
    > Each figure needs to be controlled individually and preferably serially
    does
    > anyone have an idea of a good driver to do this ?
    >
    > Justin
    >
    >
    > 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 2001-09-06 16:04
    At 09:55 AM 9/6/01 -0400, you wrote:

    > >Each figure needs to be controlled individually and preferably serially does
    > >anyone have an idea of a good driver to do this ?

    Our EDE707 provides control of up to eight 7-segment displays (common
    cathode or common anode), and also provides counter up/down and reset to
    zero functionality along with leading zero blanking and lamp test. Control
    is via 4 bit parallel bus. Datasheet and pricing information is at
    www.elabinc.com in the EDExx IC section.


    Todd Peterson
    E-Lab Digital Engineering, Inc.

    (816) 257-9954 FAX: (816) 257-9945
    www.elabinc.com
  • ArchiverArchiver Posts: 46,084
    edited 2001-09-06 17:20
    In a message dated 9/6/01 9:12:52 AM Central Daylight Time,
    cpuman3@h... writes:


    > You consider the Max7219? You can daisy-chain-ish 2 Max's together to
    > support up to 16 digits. It only costs $20 per chip and uses the shiftout
    > command on the basic stamp.
    >

    If cost is a factor you can chain eight 74HC595s together and use SHIFTOUT as
    well. The 595 is only 50 cents per part, but doesn't do some os the cool
    things the MAX7219 does (like BCD decoding and brightness control).

    -- Jon Williams
    -- Applications Engineer, Parallax.



    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-01-24 19:21
    Is there a chip which decodes byte or nibble to 7 segment displays and
    handle the repeated strobing of the digit display .
    I want to write out 4 characters to a set of 4x 7 segs using a stamp and not
    worry about the overhead


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-01-24 19:46
    The Maxim MAX7219 is designed for just that purpose. There is a Nuts
    & Volts column on it.

    --- In basicstamps@yahoogroups.com, Sadler Porter
    <porter.sadler@s...> wrote:
    >
    >
    > Is there a chip which decodes byte or nibble to 7 segment displays
    and
    > handle the repeated strobing of the digit display .
    > I want to write out 4 characters to a set of 4x 7 segs using a
    stamp and not
    > worry about the overhead
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-01-24 20:00
    At 02:21 PM 1/24/03 -0500, Sadler Porter wrote:

    >Is there a chip which decodes byte or nibble to 7 segment displays and
    >handle the repeated strobing of the digit display .
    >I want to write out 4 characters to a set of 4x 7 segs using a stamp and not
    >worry about the overhead

    A part I used to use (many years ago) is a CMOS part: 4511. This takes in
    4 bit data and has a latch as well as a 4 bit to 7 segment decoder.

    It should still be available from many sources - try searching for
    CD4511. Note that the first 2 letters will change, depending on the
    manufacturer. The prefix CD refers to National Semiconductor.

    I should mention, though, I haven't needed to use anything like that in
    many years. I now generate the 7 segment data inside the micro and send it
    to the displays as a serial bit stream feeding into shift registers. Much
    cheaper and takes less pins. Take a look at the SHIFTOUT command for
    examples on how to do this. In your case, I'd use 4- 74hc595 or TPIC6595
    shift registers chained together and do all this using only 3 pins on the
    micro (or stamp). Even better - all 3 of those input pins can also be used
    as inputs if you structure your program properly.

    The main difference between the 74hc595 and TPIC6595 is that the outputs on
    the hc part are totem-pole outputs - this means that you have to operate
    your 7 segment displays from the same power supply as the micro. The TPIC
    part has open-drain outputs which allows you to operate common anode
    displays from your un-regulated supply. This spreads the power dissipation
    over the segment current limit resistors instead of concentrating it at the
    voltage regulator.

    dwayne

    --
    Dwayne Reid <dwayner@p...>
    Trinity Electronics Systems Ltd Edmonton, AB, CANADA
    (780) 489-3199 voice (780) 487-6397 fax

    Celebrating 18 years of Engineering Innovation (1984 - 2002)
    .-. .-. .-. .-. .-. .-. .-. .-. .-. .-
    `-' `-' `-' `-' `-' `-' `-' `-' `-'
    Do NOT send unsolicited commercial email to this email address.
    This message neither grants consent to receive unsolicited
    commercial email nor is intended to solicit commercial email.
  • ArchiverArchiver Posts: 46,084
    edited 2003-01-24 20:10
    If you want to use just one chip, you can use the MAX7219. With it you can
    control up to eight 7-segment displays in digit mode or segment mapped if you
    choose (you can control which are docoded as digits or segment mapped -- and
    they can be mixed). You can also adjust the brightness from the Stamp. All
    this happens through just three I/O lines ans some SHIFTOUT statements; the
    MAX7219 does all the hard work.

    -- Jon Williams
    -- Parallax

    In a message dated 1/24/2003 1:38:44 PM Central Standard Time,
    porter.sadler@s... writes:

    > Is there a chip which decodes byte or nibble to 7 segment displays and
    > handle the repeated strobing of the digit display .
    > I want to write out 4 characters to a set of 4x 7 segs using a stamp and
    > not
    > worry about the overhead



    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-01-24 23:37
    If I'm not mistaken, the MAX7219 also multiplexes, resulting in less total
    power used. i.e. It only powers one 7-seg at a time but switches between
    them so fast you don't see them flickering. I found that just running 2
    7-segs directly heated up my 7805 quite a bit, even with a honkin' heat sink
    it was running over 100F.

    Original Message
    From: <selket_10027@y...>
    To: <basicstamps@yahoogroups.com>
    Sent: Friday, January 24, 2003 11:46 AM
    Subject: [noparse][[/noparse]basicstamps] Re: 7 Segment Displays


    > The Maxim MAX7219 is designed for just that purpose. There is a Nuts
    > & Volts column on it.
    >
    > --- In basicstamps@yahoogroups.com, Sadler Porter
    > <porter.sadler@s...> wrote:
    > >
    > >
    > > Is there a chip which decodes byte or nibble to 7 segment displays
    > and
    > > handle the repeated strobing of the digit display .
    > > I want to write out 4 characters to a set of 4x 7 segs using a
    > stamp and not
    > > worry about the overhead
    > >
    > >
    > > [noparse][[/noparse]Non-text portions of this message have been removed]
    >
    >
    > 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/
    >
    >
Sign In or Register to comment.