Re: MPC823 passive lcd (video controller)

Jun 23, 2003 2 Replies
J


Hi Group,


> I m having problems with MPC823 video controller and passive lcd
> panel. First i have tried to use lcd controller, but someone told me
> that i cant obtain necessary signals for Hitachi SX14Q001 with it.Then
> i started to init video controller.
> I think i couldnt understant the video controller at all (Especially
> the background color part). However i achieved to obtain proper sync
> signals with arranging ram array.
> Everything seems right from oscilloscope.(Include data signals) but
> panel shows nothing.(And i m sure it s working properly) I m filling
> frame buffer with 0xff so i m ecpecting to see white color but its
> just blank.

What's the difference between all white and all blank?



Fill it with something that will turn some pixels on and some off. Then if you see all blank, you KNOW something is wrong.


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J

if

I expected one bit per pixel. You've got three bits in an 8-bit byte. The same principle applies, though: fill with a pattern, so you KNOW what you should be seeing, and use what you're actually seeing help you diagnose the problem.

I looked up the Motorola summary on the part. It looks like a fairly complicated puppy, and I'd be real hesitant to try to diagnose anything without having spent a fair amount of time reading the data sheets and app notes, and then I'd want to spend some quality time with a scope and/or a real logic analyzer.

The summary does say it has both a video controller and an LCD controller. My first really stupid question is: are you setting up the video controller or the LCD controller or both or what?

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A

I m setting video controller up.As i said before i believe i cant obtain sync signals of this panel with lcd controller.(I dont know if all passive panels has signals as silly as this one but it s making me crazy) anyway if you think (or know) that i can obtain signals with lcd controller please inform me.(I have tried once and saw HSNC but VSNC was slightly visible from oscilloscope) Thanks again...

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