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Rockford,IL
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I recently purchased a 256 x 128 Graphic LCD screen from all electronics. I have been unable to find an Arduino library for it so I am thinking of making my own. I am also unable to get the screen to display anything. The data sheet it came with was for an HG25504 and the documentation doesn't really cover initialization of the LCD (if it does I'm not understanding it). I guess my main question is does anyone know generic pseudo code for intializing graphic LCDs? Is initialization for all graphic LCDs the same?
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The data sheet it came with was for an HG25504 and the documentation doesn't really cover initialization of the LCD (if it does I'm not understanding it).
You may have better luck with the datasheet for the controller which I believe is an SED1330.   Certainly the quality of the printing will be better than the one I found for the HG25504 at All Electronics. 

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I am also unable to get the screen to display anything.
If you look at the pinout you will see that pin 4 is labeled 'Operating voltage for LCD (variable)'.  You have to supply a variable negative voltage to this pin and adjust it for a good display.  Many displays have a negative power source right on the pc board, but this one does not.

Once you get your LCD voltage taken care of you should start looking into GLCD libraries.  Look for one based on the controller part number rather than on the display part number.


Don
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Rockford,IL
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You may have better luck with the datasheet for the controller which I believe is an SED1330.   Certainly the quality of the printing will be better than the one I found for the HG25504 at All Electronics. 

I believe there is a total of 31 pins available on this board (I don't have it in front of me right now). But I have only been using pins 1 - 17 which is how many pins are on the datasheet. There is an obvious distinction between pins 1-17 and 18-31. Does the HG25504 handle pins 1 - 17 and the SED1330 controls 18-31?
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Michael and I looked at that display a couple of years ago when we
were doing the glcd v3 library updates. Michael even bought one for testing.
We never managed to get around to supporting it.
From I remember it looked possible to support it in the glcd library given that
much of the low level control logic in the newer glcd v3 code is all driven by conditional macros.

It is a much more intelligent display than the ks0107/ks0108 or the SED1520 interface
so the support for the 1330 would be based on  only using the graphic portion of the display.
i.e. you would't get support for the modules built in text capabilities.

I just went back an looked at the 1330F data sheet and I can't quite tell if the display
memory is mapped the same as the other displays.
The other displays use 8 bit pages that advance left to right and then the pixel bits
advance top to bottom within each page.

If the display memory maps that way, then the glcd library could be made to support
that display (in graphic mode) by creating the device specific header
files with the low level control macros.
That said, given that the commands are a bit different, the actual mainline code would probably
also require some tweaks to accommodate the difference in how the addressing and write/read commands
work.

--- bill
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Does the HG25504 handle pins 1 - 17 and the SED1330 controls 18-31?

I believe that HG25504 may identifiy the LCD module (the printed circuit board with the display, controller, and other components) whereas SED1330 identifies the controller chip (one of the epoxy blobs on the pc board).  You would need a decent datasheet for the HG25504 to figure out pins 18 - 31.


Don
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Rockford,IL
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I believe that HG25504 may identifiy the LCD module (the printed circuit board with the display, controller, and other components) whereas SED1330 identifies the controller chip (one of the epoxy blobs on the pc board).  You would need a decent datasheet for the HG25504 to figure out pins 18 - 31.

The module, on the back, says Hyundai HG25604-B. There is a sticker on an IC that says HG25504 and then an IC that has SED1330 on it. I think I need to do some more digging on the SED 1330 data sheet. I have only been trying to google either the hg25404-B or HG25504.
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You have to supply a variable negative voltage to this pin and adjust it for a good display.

I was getting black lines and this was with just a potentiometer hooked up to Vo, no negative voltage supply. does this still need a negative supply even though I am getting lines, or does that indicate that it will be fine without one?
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...and this was with just a potentiometer hooked up to Vo...
A potentiometer has three terminals, where were the other two connected?

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... or does that indicate that it will be fine without one?
It's not likely since the data sheet shows a typical value of VO to be -10.1 Volts if VDD = +5 V.

Don
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A potentiometer has three terminals, where were the other two connected?
Haha, I guess you had to ask.

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It's not likely since the data sheet shows a typical value of VO to be -10.1 Volts if VDD = +5 V.
I saw that, trying to avoid it so I didn't have to incorporate and additional source into my project. Right now I am past the point of wanting to include this in my project and just want to figure out how to make it work.
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...and just want to figure out how to make it work.
Maybe you should transfer to Cornell (that's a hint).

Don
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