yolk
Beta Tester
Reged: Dec 13 2005
Posts: 15
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Hi all !!
Here is an interesting task i am working on just for the fun of it - i have a 320 X 200 graphic lcd made by Optrex which is a black and white lcd. this lcd does not have an onboard controller so it is up to us to create it. this lcd has 4 data bits and some more controlling bits (CP, FLM, LP and M) which should be synchronized according to the datasheet timing chart (i attached it) .
since this lcd is quite big in terms of pixel count, (and therefor memory needed for each picture to be displayed), i decided, as a given starting condition, that my "image" is the value 0011 that wil be connected allways to the data port ( i connected the data port to GND GND VCC VCC directly) so actualy my image is a simple black and white stripes - i just have to create the correct timing for the pixels to be loaded while the data is allways the same.
i will be happy to share this with anyone who is interested ...
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lucky
Microchip staff
Reged: Oct 06 2003
Posts: 1206
Loc: Brisbane, Australia
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Quote:
Here is an interesting task i am working on just for the fun of it...
Good luck with that. What chip are you using to control it? and once you are able to control the LCD, what are you going to do with it? Are we going to see a new version of Tetris? 
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Matt Luckman
Microchip Technology Inc.
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yolk
Beta Tester
Reged: Dec 13 2005
Posts: 15
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currently i am using the 18F452 ...
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yolk
Beta Tester
Reged: Dec 13 2005
Posts: 15
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and the goal is to be able to control the lcd so that it can be used to whatever application one wants.
i believe that once we know how to control it, some functions can be written for various purposes (fonts generating, icons and even little games...).
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nono240
Reged: Feb 09 2005
Posts: 76
Loc: FRANCE
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Hi,
I'm using those sort of graphical LCD for years now attached with S1D13700 / S1D13305 / SED1335 LCD controllers, and before planning to use a dedicated controller, we planned like you to implement ourself this tiny controller...
Those LCD requires a very fast pixel timing to display correctly (ie without flicker) -> a 60Hz refresh rate assume a pixel clock of 60*(320*200)/4 = 960KHz !
Using a 10MIPS processor (40MHz PIC), leave you approximatively 10 instructions to supply the 4 pixel/data to the LCD...
Moreover, those LCD need permanent refresh even for a statical display, since they don't embed ANY memory.
Dedicated controllers like S1D13700 have a lot of nice features like virtual screens : you can overlay up to 3 INDEPENDENT screens (ORed/XORed/ANDed together to choose). For example, i'm using one screen for statical bitmap (backgrounds, static text, graphical objects), one screen for text purposes, and the last for dynamic drawing (lines, curves, simple animation, ...).
Refreshing one screen don't need to redraw the others.
Good luck
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In a world without walls nor Windows, who needs Gates ?
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John Payson
Reged: Oct 16 2003
Posts: 1254
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I've designed a system to use a controllerless LCD (320x240 showing 4 grayscales). Getting the four grayscales to appear without flicker required a 100fps frame rate; if you don't need grayscale, you could probably get by with 40fps.
At 40fps, you need to generate 9,600 lines of data per second. Each line of data will be eighty nybbles. If you send data constantly, that's a rate of 768,000 nybbles/second. A PIC could do that, but wouldn't have time to do much else.
If you don't need the full resolution of the display and could live with, e.g. 80x60, then things would become much easier. You could wire all of the display data pins to an SPI data output, and clock scan lines in groups of four. This would reduce the output requirement to ten bytes/line and 2,400 lines/second or 24,000 bytes/second. This starts to become entirely reasonable.
If you want to give yourself a little more versatility, you could connect D0 and D2 to one PIC port pin and also, via 1K resistor, to the shifter output; connect D1 and D3 just to the shifter output. If you do that, you could select, on a per-byte basis, to output black on white, black on "gray", or white on "gray". If you connect all of the data pins to PIC port pins, you may be able to produce higher-resolution output on a small part of the display while using big blocky (and fast) low-resolution output for most of it. Some tricks would be needed to mix vertical resolutions, though.
If having a big 80x60 display would be useful, using a 320x200 display driven by a PIC may be practical. But I wouldn't expect a PIC to drive such a display at full resolution--at least not without substantial hardware assistance.
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svt_gEEk
Reged: Oct 31 2006
Posts: 1
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Hi, I'm trying to get my LCD which uses the S1D13700 controller to initialize and I'm having trouble doing so. I am driving it with a PIC 18f4620. Can someone help me? I've been going at this for DAYS and can't get anything to display. If you are willing to help me please shoot me an e-mail at asn15@msstate.edu. Thanks in advance.
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a_farhan1
Reged: Dec 07 2006
Posts: 1
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I also want to control 320*240 colour LCD model. Controller is not inside. I will try to use SID13706. This is the first time I am controlling such LCD's. Can anybody tell me what is the meaning of the signal CP, LP and FLM.
Thanks for the answer
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selim54
stranger
Reged: Dec 29 2007
Posts: 2
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hi
i want to investigating the products.I wonder if i use pic or I8051 how should i control lcd .Is there any code or do you use macros to control lcd.Can you give in formation.Thank you
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selim54
stranger
Reged: Dec 29 2007
Posts: 2
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Hi i wanna know how should ı control lcd and external memory with hitech compiler.İf you have any sample code please send.Thank you
Selim SARAÇ
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