Help with SED1330

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I purchased a Hyundai # HG25504. 5.8" x 4.58" graphic display module from all electronics corp(U.S. $18.50) It uses the SD1330 driver chip.I'm Looking for asm routines to drive it. Anyone have any experience with this display? I have used the HD1854 character LCD but this is my first graphics lcd. I also need suggestions with the 18vdc needed to drive it.I don't want to accedently fry it so I'm asking first before I smell the all to familier scent of burnt circuits. I plan on using a AVR8515 or AVR8535

Thanks![/code]

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First I want to apologize for yet another LCD thread, I meant to post it in a existing thread.
I found some posts on here about the SD1335 but the links they provided were dead. And I need more help with the power than the code(I have found a few C code segments, and one asm segment already posted here)

Troll, your a mindless jerk who will be the first against the wall when the revolution comes.

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Its hard to visualize someones workbench. An ideal situation would have a nice bench supply. Are you sure you dont need minus voltage for the lcd contrast?? I bet the electronics uses 5V.

Imagecraft compiler user

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Yes, you are correct (im missing the - sine) oops. And yes the electronics are 5v , but the datasheet calls for -18Vdc to the VDD(or maybe -15 v it's very blurry on my printout) http://www.allelectronics.com/sp...
I do have a 15 volt bench supply I'm just afraid to connect it without asking for advice first. Should I connect it the same way that I do the contrast when using the HD8515 base lcd's?

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Ooops there I go again I meant the HD1854 LCD, sorry my brain is not working right today.

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The contrast voltage just needs uamps. Use a series resistor as a 'cork' to keep the smoke in.

Imagecraft compiler user

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This is why I ask these things, :) Alright ,
I'll try using my 15 volt bench supply with say a 47K resistor and a 10K pot to trim. Gives me <2.6 uamps to Vo

Thanks for your help

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Read the data sheet very carefully.

You'll find that the -18 Vdc (Vo) is referrenced to Vdd (+5), not Vss (common), so what is actually needed is about -13Vdc in relation to common. This is the contrast adjustment, getting it wrong will result in a totally blank or black screen, needs to be set somewhere in between.

There are several informative threads that can be found by searching the forums for "HG25504"

Stan

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Remember that a bit of -V, right around the level you need, can be "stolen" from many RS232 driver chips like MAX232. IIRC the contrast circuit won't need much juice, but your display could be different.

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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OK I got it connected. Turns out a -12Vdc for Vo (-15 referrenced to Vdd (+5)) did the trick I used a 2k Pot to trim.

P.S. Lee I think you need a shave.

Tom

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Update: the -12 was wrong for this screen as everything was very dark(it shouldnt have worked at all) I'm now using +20v(+15 ref to the +5Vcc) fortunatly I was shorting my ps to the screen thats why It worked(for once my sloppy bench did some good)
Any sugestions for a more permanent supply for the screen? I am using a max232 chip in the project. I'm thinking a DC to DC converter to bring the +5 up to +20 as I only need a few milliamps.

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Probably MAX232 wouldn't give you the V's you need, but with an spare pin (or a 4049, or a CMOS gate) you can generate a nice square wave, and with a handful of schottky's and caps you can do a capacitive pump to supply you'r LCD.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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I tried using two ICL7660 charge pumps as a voltage inverter-doubler to generate -15V for Vo. It didn't work very well as the contrast would decrease significantly as more and more pixels came on. The HG25504 data sheet Electrical Characteristics specifies 5 mA typical, 7.5 mA max operating current required at Vo (for Vdd-Vo of 15.1V), which the LCD bias voltage is developed from. For the HG25504 simple charge pump devices, including the MAX232, doesn't work very well for a finished project. Suggest using a regulated or low impedance negative supply for Vo.

Stan

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Update- Do not put +20V to contrast! oops! My -12V was working fine just dim. Oh well I just souldered in a new 6246 sram and put the correct -10 v to the display and I'm back In business. Still looking for a good PDF of the datasheet. The very Blurry printout from All electronics is not helping. How can you wire these thing up when you cant see the - sign on the datasheet.