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List:       linux-arm-kernel
Subject:    RE: interfacing TFT LCD, sustaining vague datasheet,
From:       "Singh, Ajay" <ajaysingh () ti ! com>
Date:       2005-06-30 13:40:45
Message-ID: A8A67F242940E246A515077CF9ECACC157F0BC () dbde01 ! ent ! ti ! com
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I worked with Sharp Microelectronics TFT LQ057Q3DC02 and the following
values worked for me. 

	60,   /* hfp            */
	60,   /* hbp            */
	12,   /* hsw            */
	4,    /* vfp            */
	8,    /* vbp            */
	0,    /* vsw            */
	255,  /* ac bias        */
	0,    /* ac bias intrpt */
	16,   /* dma_burst_sz   */
	16,   /* bpp            */
	255,  /* fdd            */
	4,    /* lcd_clk        */
	2,    /* pxl_clk        */
    0,    /* tft_alt_mode   */
    0,    /* stn_565_mode   */
    0,    /* mono_8bit_mode    */
    0,    /* invert_pxl_clock  */
    0,    /* invert_line_clock */
    0,    /* invert_frm_clock  */
    0,    /* sync_edge         */
    0,    /* sync_ctrl         */
    0,    /* raster_order      */ 


~Ajay.

-----Original Message-----
From: linux-arm-kernel-bounces@lists.arm.linux.org.uk
[mailto:linux-arm-kernel-bounces@lists.arm.linux.org.uk] On Behalf Of
tien vuong
Sent: Thursday, June 30, 2005 6:06 PM
To: linux-arm-kernel@lists.arm.linux.org.uk
Subject: interfacing TFT LCD, sustaining vague datasheet,finding a way
to get through

Hello everyone!

My question is off topic. I just hope embedded men around here may help
me.

I am programming the S3C2410 MCU interfacing with Samsung LTV350QV-F04
TFT LCD. Now the job is coming to the condition that only these values:
VBP (Vertical Back Porch) VFP (Vertical Front Porch) VSPW (Vertical Sync
Pulse Width) HBP (Horizontal Back Porch) HFP (Horizontal Front Porch)
HSPW (Horizontal Sync Pulse
Width) is needed to be programmed properly. I am saying this by the fact
that I have used oscilloscope to probe all output ports (DOTCLK, HSYNC,
VSYNC, Data,
...) to verify that output signals are good match with waveforms and
frequencies in datasheet, and I could see some thing display on screen
also. Though I can probe data ports to verify that output data is all
correct (simple test is filling the screen with a single color so that I
can know what data must be in each data port to compare with probe
result), but what display on screen is absolutely unexpected.
Unfortunately, required waveforms and frequencies don't restrict the
values of VBP, VFP, VSPW, ....(different values of them all make output
signals that satisfy waveforms, I hope I am not wrong at this point). So
I think the remaining problem is just how to give VBP, VFP, etc proper
values. Unfortunately, the LCD datasheet is quite vague at this point. I
have no way but to sustain this vague datasheet. I am doing hundreds
test to try different combinations of values.
I feel that I am in so bad condition now, no method, just try and fail.
Some tests showed better result than the others but none was acceptable.

I wonder if someone masters the working principle of TFT LCD can say
something like:
The test is filling screen with one color then:
-if the display color is wrong color then must change values of
.....(?)......
-if only left half of the screen is filled then must change values of
......(?).....
-if only bottom half of the screen is filled then must change values of
......(?).....
-if scattered vertical line is displayed then must increase values of
....(?).....
-if scattered horizontal line is displayed then must increase values of
....(?).....
....
I have a thought that this is the way to approach to the proper values.
But I can answer none of above questions.

Any one who experienced with programming LCD device driver please give
me some advice for this issue.

Best regards,
Tien


		
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