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16 segment led driver/decoder with user loadable charset exists? — Parallax Forums

16 segment led driver/decoder with user loadable charset exists?

CuriousOneCuriousOne Posts: 931
edited 2013-05-25 23:34 in General Discussion
There is MAX6599, it has built in charset for ASCII codes, but i want to add some custom letters. I know that such IC do exist - I have seen chinese datasheet for it, but lost it somehow.

P.S. I know that I can send arbitrary bytes to get segments on according to my needs, but built in character generator would be much more nicer.

Comments

  • PJAllenPJAllen Banned Posts: 5,065
    edited 2013-05-22 19:07
    This could be done effectively and inexpensively with any of several microcontrollers, running on their own (internal) timebase, using clocked serial or possibly parallel input. Adding a couple of data latches (SIPO) for outputs would make for a lean, mean machine.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-05-23 06:30
    You could do this in SXB with Parallax's SX chips or with PIC.

    Most of the effort would be to provide a serial or parallel port for directing the device to look up the received code and convert it into a display character of your choice.

    Even a BasicStamp2 can do this as it already has an RS232 port, plus 16 i/o pins available to drive the LED. It may be a good choice to do a proof-of-concept as a first step toward programing a much less expensive device in assembly language.

    What are you looking for in custom characters? Special language specific characters? Russian crylic? Hebrew? Arabic? Mathematical Symbols? Currency Symbols?

    Eventually, you just have to abandon the 16 LEDs and go to a 5x7 or even better, a 32x32 dot matrix and Unicode to include the world.
  • CuriousOneCuriousOne Posts: 931
    edited 2013-05-23 06:46
    I actually want to save my time, by avoiding unnecessary programming. So this is why I'm seeking for ready made IC.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-05-23 10:43
    And that is why they make this rather expensive chips, but they won't do the custom graphics that you might be inspired to do. Generally that just interpret ASCII and numbers in a nice tidy manner.
  • CuriousOneCuriousOne Posts: 931
    edited 2013-05-24 13:08
    I have backup of my PC image of time when as I remember, I had that datasheet. Will restore it this weekend and see if it helps.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-05-25 11:01
    Why not just tell us what special characters you desire. Someone may know if something exists.

    An SX28 has enough i/o pins to do this from scratch and you may adapt an 8 bit format to provide the usual ASCII in 128 slots, and another 128 slots for special items. If the input is SPI, it doesn't even require an external crystal to operate, just 5VDC
  • kwinnkwinn Posts: 8,697
    edited 2013-05-25 23:17
    CuriousOne wrote: »
    I have backup of my PC image of time when as I remember, I had that datasheet. Will restore it this weekend and see if it helps.

    Quite a few of those older decoder/drivers have been discontinued since cheap microcontrollers make doing that very simple. If that is the case you could use eeproms or software to do the same thing.
  • wasswass Posts: 151
    edited 2013-05-25 23:34
    Did you mean to type MAX6955 not MAX6599?

    The MAX 6954/6955 are interesting chips they use Charlieplexing to drive 8 16-segment LED displays with only 18 output pins instead of the obvious method that requires 24 pins.

    http://www.maximintegrated.com/app-notes/index.mvp/id/3212

    The MAX6850 does what you need (ASCII + 24 user-definable characters) but it's for VF displays and is no longer in production.

    http://www.maximintegrated.com/datasheet/index.mvp/id/3636
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