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LCD Segment driver — Parallax Forums

LCD Segment driver

ArchiverArchiver Posts: 46,084
edited 2000-04-20 02:58 in General Discussion
Does anyone have any experiance driving a 7 segment LCD device directly like
the unit VL-322 (is like regular 7 segment LED). I have looked at some of the
BCD version out there but that ties up a lot of i/o(stamp2) for a 3 digit
display. Any info would be great.

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-04-18 18:39
    At 07:30 AM 4/18/00 -0400, you wrote:

    >Does anyone have any experiance driving a 7 segment LCD device directly like
    >the unit VL-322 (is like regular 7 segment LED). I have looked at some of
    the
    >BCD version out there but that ties up a lot of i/o(stamp2) for a 3 digit
    >display. Any info would be great.

    I haven't done this, but it has occurred to me that a nice 3 digit display
    could be made with one of those cheap LED or LCD volt meters. These things
    could be driven via PWM from the stamp to display any value.

    Just an idea, Duncan
  • ArchiverArchiver Posts: 46,084
    edited 2000-04-20 02:58
    > Date: Tue, 18 Apr 2000 07:30:24 EDT
    > From: electronguy@a...
    >
    > Does anyone have any experiance driving a 7 segment LCD device directly
    like
    > the unit VL-322 (is like regular 7 segment LED). I have looked at some of
    the
    > BCD version out there but that ties up a lot of i/o(stamp2) for a 3 digit
    > display. Any info would be great.

    You can drive a 3, 3.5 or 4 digit LCD display from a Microchip 40 pin
    AY0438 LCD driver chip (available from Digikey). It only takes 3 stamp
    pins.
    The hard part is working out the interconnection between the 40 pin
    driver chip with the 40 pin LCD display. See my
    http://www.infiltec.com/inf-dm1s.htm
    for an example of a device using this chip to drive a 3.5 digit LCD.

    Hope this helps,

    Dave Saum
    Infiltec
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