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Voltage requirement for a HR-TFT Sharp
http://forum.lcdinfo.com/viewtopic.php?f=6&t=748		 Page 1 of 1
Author:  246tNt [ Tue Jul 13, 2004 9:11 ]
Post subject:  Voltage requirement for a HR-TFT Sharp
Hi

I don't understand all the voltage requirement of this lcd :
http://www.246tnt.com/lq039q2ds53.pdf

Well, it needs an inverter for the backlight, that I know. Then
what about the others :
VDD
VCC
MOD
VSS
VEE
VCOM
VSHD
VSHA
V0 - V9

And what voltage should I use for the data/clock pins ?

Thanks for any help you may provide,

246tNt
Author:  Henri [ Tue Jul 13, 2004 9:58 ]
Post subject: 
From the electrical characteristics table in the datasheet these can be read:

VSHA +5V
VSHD +3.3V

Then it seems to say that V0-V9 need some alternating voltage between 0V and VSHA. This is better explained in the datasheet.

VDD +15V
VSS -15V
VEEDC -9.0V

You should get better idea from the electrical characteristics table from the datasheet.

But uh, if you don't need to use just this panel I think a better alternative would be a panel with simpler voltage requirements and which might be also simpler to drive.
Author:  246tNt [ Tue Jul 13, 2004 10:55 ]
Post subject: 
To drive it, I plan to use a FPGA with a 1M SRAM frame buffer.
But I'm not that good at analog electronics ... But I've just found a document

http://www.erd.epson.com/vdc/pdf/1376/x31bg011.pdf

That explains what I need with schematics. Apparentry some voltages are AC biased with a DC component.

V0-V9 are dc voltages that represents de "Gamma curve".


I like theses LCD because they costs 10$ ;)
Author:  Henri [ Tue Jul 13, 2004 12:09 ]
Post subject: 
That Epson document looks very good for this display. Should explain the needed power supplies.

And now that you mentioned that you're planning to use FPGA to drive it that tells me that you should know what you're doing and there's hope that you'll get it working ;) It's not always easy to know in this forum how much the other person knows about the subject and how to approach the problem.

If you still have something that is not so clear about this I can see if I understand enough of it to be of help.
Author:  246tNt [ Tue Jul 13, 2004 14:25 ]
Post subject: 
Henri wrote:
That Epson document looks very good for this display. Should explain the needed power supplies.


Yes indeed ;)


Henri wrote:
And now that you mentioned that you're planning to use FPGA to drive it that tells me that you should know what you're doing and there's hope that you'll get it working ;) It's not always easy to know in this forum how much the other person knows about the subject and how to approach the problem.


I'm more a programmer, but I know digital electronics quite well too. Analog on the other hand always seemed a bit obscure ;)

And it's true that it's always pretty hard to know what the guy you're "talking" to knows. I would certainly not recommend trying to use this LCD to a beginner trying to hook it up an a LPT port ;)


Henri wrote:
If you still have something that is not so clear about this I can see if I understand enough of it to be of help.


Well maybe later ;)
I plan on making a little controller to interface it with a PC and resell the modules at costing price ( I'm forced to buy pieces by 20 and I only need 3-4 for me so that leaves me with some modules unemployed ). Having lcd info support maybe nice.
Author:  Henri [ Tue Jul 13, 2004 22:34 ]
Post subject: 
I have been thinking of doing something similar of what you are planning. First I just need to get some FPGA development board.
I've been looking at the new $99 Spartan 3 development board with 1MB SRAM included from Xilinx/Digilent. It will probably cost me about €150 after all the taxes :cry: but still it seems like the best option at the moment.
Author:  246tNt [ Wed Jul 14, 2004 9:25 ]
Post subject: 
Yes, that spartan 3 kit looks fine. With the tax & shippin here in Belgium, it should be around 135€

But I'll soon have the spartan 3 kit of AvNet (399$) with PCI, VGA out, 1M SRAM ... And this one is payed by the company I work for ;) There is also another board for arount 200$ wich has 64Mb SDRAM 8Mb Flash, it looks cool too. Personnaly I would like a board with PCI, VGA, SDRAM, FLASH et GPIO (for the LCD)

I think I'll try to design a small bard with a Spartan 2XL ( These one can easily be bought on DigiKey ) or a Spartan 3 if I can get Engineering Samples. Some cheap Serial flash, some SDRAM or SRAM and a little 8bit microcontroller, and USB interface too would be nice.
Author:  246tNt [ Fri Jul 16, 2004 23:34 ]
Post subject: 
...

My contact in the US just let me down.


If you are in the US and willing to help me buy some TFT screen at about 10$ piece please contact me.

The idea is that I order 15 for me, x for you and make them delivered to you. You ship me the 15 by DHL and you keep the rest.

DHL shipping to me from US is about 100$, so if you order 10LCD that's ok. If you order less than 10 then I can send the difference by PayPal ...
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