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Lcd mod. Issues with video signal

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goatnad

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Hello all. I am new to this forum and new to working with electronics. I need whatever help you guys can give me. Ok to start i have done research on my screen and have come up with alot of info. first off will be the pdf's i have found.
chipset is vp77
and lcd is AT070tn01 v.2
well i would post them but i have not posted yet so it wont let me.


i managed to get the power for the backlight running but now i am working on wiring an s-video cable or composite rca cable up to this lcd so i can use it in a carputer. I have found what most of the wires i have do but not all of them. here is what it looks like for the pinout on the board

IGND (no wire)
VGH (Positive power for scan driver)
VEE (not sure)
VCC (Supply voltage for logic control circuit scan driver)
VDD (video digital input)
VIN (not sure, no wire)
VSS (needed for power)
GND (Ground)
NTPC (not sure)
CVBS (Composite video input 1)
AGND (i think another ground)
SDA (Serial I/F data in/out)
SCL (Serial I/F clock)

i cant figure out which lines would work for a s-video connection and i have already tried wiring to cvbs up to a rca cable but still no picture. any help you guys can give me would be wonderful and if anything i have typed is wrong let me know. I can add pictures of the lcd and board if need be. thanks ahead of time
 

qieda

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Hi,

I do not have a datasheet,
(I only found https://www.pc8888.com/pdf/AT070TN01 .pdf on the internet)

but from the names I would guess

VEE => negative supply ??? or Ground ??
VDD => I think this is a supply ???
VSS => I think this is Ground ???
NTPC => switch between NTSC (if high?) and PAL (if low?) ???
SDA (Serial I/F data in/out) yes it looks like a I2C bus
SCL (Serial I/F clock) yes it looks like a I2C bus
 

goatnad

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thank you very much for the quick reply. wow it was really fast. i wish it would let me link the pdf's i found for the screen. ok i found another site last night explaining what those mean and your right on with what you stated. the sda and scl is something they called a 2 wire serial connection. they are necessary cables. i only have 5 wires connected as of right now and the screen still displays. now i need to figure out which 4 wires i need to wire into an s-video cable. any luck you could help me with that? ive tested voltage on all the lines and found the scl and sda both run 5v while the Vss runs 9 volt. only other lines hooked up is the cvbs( its 2 wires. the cvbs wire and a ground.) thank you again for your help.

---------- Post added at 12:57 ---------- Previous post was at 12:39 ----------

pdf for lcd
AT070TN01 V.2-Datasheet-PdfSea

controller board
VP77 , (ETC) - Video Drcoder (VP77.pdf , VP77 pdf)

the controller board is actually a VP77-LF but the only pdf i could find was for just the VP77. figured it couldnt be that different.
 

qieda

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Hi,

when looking at the VP77 datasheet I think you need to setup the internal registers of this Video Decoder. Otherwise I do not think, that your system will work. Do you have a uC in your system, which does this job? Or do you plan to do it with the I2C interface from an external controller?

The VP77 would be able to support the s-video (means the separate Y and C channel), but from your pinning list I think you can only use CVBS (for the modulated C on the Y channel).

you mentioned Vss runs on 9V. That looks strange for me. What are the levels of the other supplies

regards
 

goatnad

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Thanks for the link. going to read over the specs when im done typing this. Also forgive me for not knowing what uC is. Im somewhat new to electronics like this. How hard would it be for me to get an external controller? The ones i looked up were 100 bucks or more and im not even sure they were the ones i needed. Could i make the external controller? I have messed around with programming so if thats needed i could figure it out. I apologize for saying Vss. I meant to say Vcc. The Vss doesnt even have a wire. I also retested the Vcc and its pulling about 7.5 not the 9 thought. Twitchy hands make it hard to read :).
 

qieda

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Sorry
uC stands for Micro Controller. e.g based on a 8051 or ARM core with an I2C interface.

You can control the I2C bus from your PC there a several adapters to buy on the internet.
e.g. in out compay we use this one
Aardvark I2C/SPI Host Adapter - USB Interface to I2C and SPI, Programmer, Bus Exerciser, Simulator for Windows, Linux, and Mac OS X - Total Phase

But
I think you can also use your grafic card to control the I2C
look at this page
https://www.paintyourdragon.com/?p=43
I have never did it this way, but I think it should be possible

regards
 

qieda

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goatnad

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well after alittle more research i have decided that i will be giving up on this lcd. i will be going with either a mini pc setup connected to a portable dvd player or i will be going with this.
Mini6410 SAMSUNG S3C6410 ARM11 Board with 4.3" 480272 TFT LCD 256MB DDR 256MB NAND products, buy Mini6410 SAMSUNG S3C6410 ARM11 Board with 4.3" 480272 TFT LCD 256MB DDR 256MB NAND products from alibaba.com

i also have the option of using one of these though i think i might be limited in its use.
7" Epad Google Android WiFi Tablet PC Touch With Camera - eBay (item 130474622511 end time Jan-13-11 10:48:19 PST)

i really want to go with the mini6410 because i could customize it more than the others. if you know of any other options let me know and thanks alot for all the help you have provided. you really helped me to understand alot about lcd's and lcd controllers.
 

qieda

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Hi,

yes the the Samsung S3C6410 looks quite flexible.
If you have a detailed specification about this chip I would be interrested to see this.

I wish a great success to your project

regards
 

qieda

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Hi,

one additional point.
If you buy such a system, you should take care that you get all required documentations.
On the Samsung chip is a ARM processer.
Do you know if in this system is already an operation system and an application running.
Or do need to write all the SW on your own.

regards
 

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