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PostPosted: Tue Mar 15, 2005 2:41 
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Joined: Wed Dec 01, 2004 8:47
Posts: 13
Hi all,

Does any one know how to speed up the LCD performance?
I am using Rabbit2000 to drive DMF5001 T6963C LCD graphic display.Howerver, it took too long at start up and too long to refresh or update the data on LCD.

On start up, i clear 3pages of Text area and graphic area using auto write mode to write an empty space character to each text position and similarly to graphic area.

I also generate BIG character on the screen by using special character GROM to write each special character on a spot and repeating this until i get the complete big character. I use auto write mode to write these character but still use normal LCD Write command to set up an address pointer, for example.

Any helps would be very appreciated,
Thank you
Wanna


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PostPosted: Wed Mar 16, 2005 19:25 
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Joined: Sun May 05, 2002 22:05
Posts: 2063
Location: Lappeenranta, Finland
If you are already using auto write mode sounds like you can't speed up there anymore.

But then the question is how fast is your access between the microcontroller and T6963C. How long does it take to update the whole screen ? Or how many times can you redraw the whole screen every second ?

If I remember correctly of some of my tests from few years ago it was possible to write to 240x128 T6963C display (update the whole screen) over 50 times per second. But I think at this speed there were already some visible errors.

Maybe you would like to post some of your code so that might give some new ideas about your problem. Is your microcontroller just that slow in port access or is there something in your code that causes the slowness.


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PostPosted: Tue Nov 29, 2005 20:03 
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Joined: Mon Nov 28, 2005 11:54
Posts: 6
hai generous people out there,
i too face the same problem of updating the display memory, i hope this problem would be solved if the processor is directly interfaced to display ram (ie the ram has to be dual ported)

I just want to know whether the above interface is feasible.

can i use dma to transfer data to display memory
If it is so how can i take care of the control signal. (currently iam taking care of the control signal using io port (byte)) ex. "RS","E" etc.

This has actually degraded my processor performance even though i refresh the screen only twice per sec.

I actually wanted to improve the refreshing of display information to sram, without degrading my processors performance

I would be glad if u could help me in finding a solution


MORE DETAILS REGARDING MY DISPLAY

Well i have a lcd module with built in controller(LC7981) +memory
192x128 dot matrix lcd (lc7981 doesnt have autowrite)

the microprocessor is taking too much time inorder to dump the display information to the lcd as a result of which the processors performance is degraded.

The increased time cause:
(1)i dont have direct access to sram, i have to access sram only throu' controller after passing suitable command words. (This has to be done for every 8 pixel of information) (192x128)/8 words has to sent. as i also have to take care of control signal i cannot use dma


If not is their any solution to solve this problem

Are their lcd modules available in the market which allows dumping of display information directly to sram rather than throu' controller (assuming sram to be dual ported )

sorrry for the poor english i have


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