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Powertip lcd graphic panel

Hi I have one of these wich im driving from a dspic30f

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but the data sheet leaves a bit to the imagination ! I have a chequor display but wich can only be seen if the scan is reduced to a crawl then only one line can be seen at a time, vee is -27v. im not sure if the contrast voltage should be 0-5v as other displays or as some1 suggested on sci.electronics.components is possibly a negative input ? anyone have any experience of this make/type of panel ?

thanks Colin =^.^=

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colin
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Well thankfully I got it working a lot better now, thanks to poly' who sugested the negative contrast voltage wich was indeed the case, I just fed it -vee through a 1M then 100kR to be safe and it displayed ok.

heres the bit bashing code ..

s=display_text[row/8]; pixels=font8bitmap+(row%8)-font8start*8; for(col=0;col>4; b&=0xf; LCD_CL2=0; LCD_CL2=1; D0_D4=b; LCD_CL2=0; } LCD_CL1=1; if(!row) LCD_FLM=1; LCD_CL1=0; LCD_FLM=0; if(++row>=no_rows) { row=0; LCD_M^=1; }

Now I just need a way to avoid making an EL driver transformer with thousands of turns.

Colin =^.^=

Reply to
colin

"colin" wrote in news:87geh.2623$ snipped-for-privacy@newsfe3-gui.ntli.net:

Would a trigger transformer for a xenon tube work for that? (I haven't thought this through, the idea just came to me so I put it forward as it is).

Reply to
Lostgallifreyan

Out of interest, what -vee level did you need to use?

Don...

--
Don McKenzie
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Crystal clear, super bright OLED LCD (128x128) for your microcontroller.
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Reply to
Don McKenzie

ok.

about -18v to -22v seems to work ok, depends on the refresh rate etc.

Colin =^.^=

Reply to
colin

not sure, but the problem is the frequency wich is a bit low +~ 4khz wich means a lot of turns at 200v to avoid saturation. trigger transformer probably only expects very short pulses although I dont know how many turns it has. needs aprox 3k turns with 12mm^2 ferrite core.

looking around a way to do it seems to exist wich uses a simple switch mode

200vdc generator and simply pulsing it on and off at 4khz. im wondering how I can combine this with the -20v bias generator.

Colin =^.^=

Reply to
colin

"colin" wrote in news:zsjeh.3833$ snipped-for-privacy@newsfe4-gui.ntli.net:

The facetious answer would be: "don't" >:) That negative voltage bias is a very low-current signal to a sensitive device, it might be asking for trouble to try to integrate those two systems.

Good idea with the switch mode supply transformer though, far more likely, and they often turn up free on all kinds of stuff.

Reply to
Lostgallifreyan

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