TFT-LCD with AT91SAM7S64

Development Boards MicroMod
1

Hi to all!

I have 240x320 TFT-LCD with RGB pattern, 18 bpp(bits per pixel). 262K color.

and AT91SAM7s64 as ARM controller.

The LCd has standard conrol signals like : HSYNC, VSYNC, MAINCLK, ENABLE and 18 Datalines for RGB control of a pixel (6 bit for each color).

Upto now i have basic concept of this signals to get LCD interfaced with microcontroller that is : VSYNC is used for reset the frame, HSYNC for changing the row of pixel and MAINCLK sequences the column on its every pulse.

RGB data gets latched on each MAINCLK pulse with ENABLE active.

But I don’t have idea how to write souce code for sending character or symbol to the LCD.

Does anybody can give me any resource on this issue?

Best Regards!

2

Why not just buy one of these:

http://www.sparkfun.com/commerce/produc … ts_id=8541

and leave the AT91 for doing other things? Driving an LCD is pretty processor intensive, so you’ll want a separate controller for that.

3

Hi agian!

Any code example on how to communicate with LCD through RGB Parallel interface will give me the clear basic view how LCD needs to be handled.

I have concept that the RGB interface can be used only if whole frame needs to get updated, but what if i need to update only some area of the screen with keeping all other area intact as before.

I dont know whether i am thinking is right or wrong

And pls consider that my LCD module has only RGB paraller interface.

So pls suggest me such source.

Regards!

4

Hi again !

If LCD module has parallel TTL RGB interface , Pls tell me, then is it compulsary to use LCD controller chips or i can directly interface LCD module with micrcontroller with AT91sam7s64 ?

Thanx!

5

You need i/o lines from the micro controller to the LCD pins.

The problem is the timing for driving those lines.

That micro you mentioned works at 55Mhz, in the best case scenario you will need 1 clock/line set-up, and you need 24+lines

So, let’s say 55Mhz/24 = 2.2Mhz update rate.

But the LCD expect the data around 7Mhz if I recall correctly.

The point is, a general micro can’t drive a LCD, or, if he manages to do it, it won’t have much clocks to spare to do anything else.

Only dedicate silicon or FPGAs ( that are also a form of dedicated silicon, but, reconfigurable) can reasonably drive them.

6

You could always upgrade to the AT91SAM9261. The device has a built-in LCD controller and source code provided by Atmel. If you want to use your SAM7 you are probably going to need an LCD controller but from what I have seen these are not fun to deal with. Just my 0.02 cents. Either way controller LCDs is a bit a work.