Alternative to the H44780 lcd controler


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  1. #1
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    Default Alternative to the H44780 lcd controler

    Is their an alternative to the H44780 lcd controller which does not require any custom routines to be written and will work with the standard LCDOUT command, because it looks like im going to have to use a custom lcd on my next project.

    Thanks Sphere..

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    Quote Originally Posted by Sphere View Post
    Is their an alternative to the H44780 lcd controller which does not require any custom routines to be written and will work with the standard LCDOUT command, because it looks like im going to have to use a custom lcd on my next project.

    Thanks Sphere..
    Directly from the PBP manual...

    Display Items on an intelligent Liquid Crystal Display. PBP supports LCD modules with a Hitachi 44780 controller or equivalent. These LCDs usually have a 14- or 16-pin single- or dual-row header at one edge.

    That being said, I can tell you from experience that it's not that hard to write routines for practically any LCD out there, mono graphics LCDs, color graphics LCDs, 'cell phone' LCDs, and so on...
    Just takes a bit of reading and practice...

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    Thanks for the reply skimask, but the problem is that I wouldn’t even know where to start. I’ve tried searching the forums for examples but the nearest I found was a custom serial out routine. I can get a display that uses HD66712 controller, which would be ideal for my project. But I cannot find any example code that would drive it. Or at least a good place to start.

    Thanks Sphere..

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    This is always a good place to start
    http://www.melabs.com/resources/samples.htm

    and on that page is this sample program. The PBP manual shows how to wire it up;
    http://www.melabs.com/resources/samples/pbp/lcd.bas

    You can learn a lot from these programs.

    Have fun,
    Bob

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    Quote Originally Posted by Sphere View Post
    Thanks for the reply skimask, but the problem is that I wouldn’t even know where to start. I’ve tried searching the forums for examples but the nearest I found was a custom serial out routine. I can get a display that uses HD66712 controller, which would be ideal for my project. But I cannot find any example code that would drive it. Or at least a good place to start.
    Thanks Sphere..
    I just googled and found a datasheet for the HD66712U controller, and while it's not a datasheet for an actual LCD, it's good enough for me.
    The datasheet says it's upwardly compatible with the HD44780, and like I said in your last bunch of posts about LCDs, from reading the '712 datasheet, it looks like it 'compatible enough' with PBP's LCDOUT commands to make it work just fine without doing anything out of the ordinary. And if it turns out that I missed something that's buried in the datasheet, the register set, the commands, the timings, all look like they're 44780 compatible, therefore PBP LCDIN/LCDOUT comapatible.
    Of course, this doesn't mean that your particular LCD module (probably with a master controller of some sort with probably a few slave controllers and maybe some other glue logic on board) follows the 'normal' way of doing things and it is actually completely PBP LCDOUT compatible. But I don't know what your 'chosen' LCD module is, so I can't comment on that. That's the problem with limiting yourself to a particular LCD module. If it doesn't work...Nothing works.
    If you're having problems with setting something up (as you seemed to be in your last thread about LCDs), then post the problems. Quite frankly, driving this type of LCD doesn't look like brain surgery, and should be a piece of cake to get running.

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    Hi bob thanks for the reply. The problem is that the H44780 is now obsolete and any new or custom designs now use a more up to date lcd controller to drive the displays, but unfortunately its not compatible with the LCDOUT command used in pic basic and would require a custom routine to be written.

    Thanks Sphere..

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    Quote Originally Posted by Sphere View Post
    Hi bob thanks for the reply. The problem is that the H44780 is now obsolete and any new or custom designs now use a more up to date lcd controller to drive the displays, but unfortunately its not compatible with the LCDOUT command used in pic basic and would require a custom routine to be written.
    Thanks Sphere..
    Not true...
    Almost every TEXT mode, parallel input LCD out there today is HD44780 compatible.
    The LCD YOU have may not be 100% compatible. All of the TEXT mode, parallel input LCDs I bought in the past 3 years (roughly 200 in about 30 different styles, shapes, sizes, etc), have ALL been PBP compatible. I can only think of one that I had to make A single custom initialization routine for. After it was initialized, it acted correctly with LCDOUT commands in PBP.

    Now, graphic mode LCDs, color LCDs, yes, that's a different story.
    But even then, there is a common theme between the bulk of the graphic LCDs (i.e. most of the routines are practically the same with a few register location changes, maybe some timing changes).
    And even the color LCDs from cell phones have similar code driving them (yes, it's different between the models, but overall, it's the same, but different, make any sense?)...

    Jist of the story...
    Post the code!
    Post the LCD module spec's!
    Post the datasheet link!
    Post it all!

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    Thanks for the reply skimask. I’m using the Batron BTHQ42003AV display, I can access line 1 and 3 using the LCDOUT command but only the first 12 characters of those lines, anything after that just copies part of what’s showing on line 1 on line 2. I need to figure out how to enable access to the rest of the display, but unfortunately this is where I draw a blank. It looks like you have to enable the EXT pin to enable access to the rest of the display but I do not know how too.

    Thanks Sphere.
    Last edited by Sphere; - 31st July 2008 at 15:05.

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    Quote Originally Posted by Sphere View Post
    It looks like you have to enable the EXT pin to enable access to the rest of the display but I do not know how too.
    I just Googled 'hd 66712 pbp' and look what came up:
    http://list.picbasic.com/forum/messa...tml?1073232023

    Then I searched '66712' here and came up with this:
    http://www.picbasic.co.uk/forum/show...hlight=hd66712

    So it seems you have the answers at YOUR fingertips...still...

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    So im I wasting my time with this display.

    Sphere.

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    Quote Originally Posted by Sphere View Post
    So im I wasting my time with this display.
    Sphere.
    No! That's the point! You're not wasting your time with this display!

    This display can and should work just fine for you...then and now.
    Will it take some reading and learning? Yes...
    Might it take a bit of reading of the datasheets and some playing around with PBP to get it to work right? Maybe...
    Might it take a few 'custom' routines to get it to work? Probably...
    (HD66712 datasheet, pages 398, 405, 411)
    Last edited by skimask; - 31st July 2008 at 17:05.

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    You could always used this LCD from Sparkfun. Looks like it may be cheaper than the one you are using and the Samsung controller is a direct replacement for the Hitachi.

    Looking at the display you are using there are somethings you need to do:
    DEFINE LCD_LINES=4
    The $FE cursor commands in the PIC BASIC Pro table for LCDOUT are not correct for this part - First line starts at x080(0x80 + 0x00), second at 0xA0(0x80 + 0x20), third at 0xC0 (0x80 +0x40), and fourth line at 0XE0 (00x80 +0x60).

    Otherwise it is the same as the HD44780.
    Tim Barr

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