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Topic: 7" LCD or similar (Read 3 times) previous topic - next topic

svalls

Hi,

I have read a little on the forum about the use of big screens, and the common answer is that it is not possible due to image size on that big screen resolutions.

However, due to the amount of text I have to show (yes: only text), I need a big screen, something in the line of 7". I've found on RS a color LCD screen with 7" and tactile sensor for 70€. I think it needs a lot of pins, something like 16 or 18.
But: It is possible to do it with a Mega?

Any library suggested?

scott_fx

this can work if you get a screen with vga input:
https://www.sparkfun.com/products/10329

or composite video connection:
https://www.sparkfun.com/products/9313


MarkT

Larger LCD screens all use VGA or VGA-like interfaces - there is no screen buffer so you have to have a VGA-like driver to interface to them.

Small LCD screens (upto about 320x240) can have framebuffer chips like the ILI9325.  These often have a simple-to-use serial or SPI interface which is easy to drive from a microcontroller (no requirement for constant refresh).

The reason for the difference between large and small screens is simple - the smaller screens have a _single_ silicon chip controller which controls source and gate lines to the TFT LCD pixels - thus it can drive pixel data from a frame buffer to the right screen pixel.

Larger screens have separate (often multiple) chips for source lines and for gate lines.  No one piece of silicon knows both the row and column information so there's nowhere to put a framebuffer (other than in an external VGA-generator chip).

With VGA style interfaces the source driver(s) handles Hsync and does serial->parallel conversion for one row at a time. The gate driver(s) handle Vsync and selecting the current row.
[ I won't respond to messages, use the forum please ]

doc_norway


I was thinking in something like that:

http://uk.rs-online.com/web/p/lcd-displays-colour-graphic/7502588/?searchTerm=750-2588&relevancy....<and so forth>


You can use that screen with an Arduino Mega (probably even an Arduino 2009/Uno but it will most likely use ALL the available pins.)
The product information clearly states:

  • Built in controller

  • 8080/6800 MCU Interface (selectable)


But don't expect fast updates :)

/Henning

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