1. Home
  2. Embedded Programming
  3. How to test a TFT with RGB in a simple way

How to test a TFT with RGB in a simple way

I'm starting a new project that will use a small 4.3" TFT LCD display with resistive touch panel and RGB interface.

I never used TFT displays in the past, so I'm not sure what is the best solution for me about the display and the controller board. I read about NXP Cortex-M3 LPC178x with integrated LCD controller and it seems good to me, mostly because I can use emWin libraries for free. But I'm not sure and I want to study other competitor's alternatives.

In the meantime I want to choose the display, so I'm going to purchase some samples and... test it. Ehm... how? Each display has a different pinout, color depth, touch screen connector, backlight interface. I haven't any problem to solder some wires between LCD connector(s) and controller board or power supply or backlight driver.

But I need a suggestion about a sufficiently generic and low-cost controller board that can be used to test a "generic" TFT LCD with RGB interface. The board should be simple to use and configure to manage the LCD sample under test.

I'm thinking about BeagleBone Black that provides an expansion connector P8 with LCD RGB interface, but I don't know how simple is to configure the embedded Linux running on the board to use the LCD under test (resolution, clock frequency, color depth, ...)

Any suggestions?

Reply to
pozzugno
Loading thread data ...

There is the STM32F429I-DISCOVERY board, this comes with a small RGB TFT with RTP. You could rip off (literally) the screen it comes with and connect your own via the expansion headers. Or perhaps it will work with the both screens connected (one scrambled probably..).

There is example software and free libraries etc, with some users projects on the web too e.g.

I would not say it is simple to use and configure, there is a learning curve for it all. The above project is probably the easiest I have found.

At that size there are displays with embedded controllers, these may be an alternative. Even SPI if you don't need a fast frame rate.

--

John Devereux
Reply to
John Devereux

Il 19/11/2014 12:54, John Devereux ha scritto:

Hmmm.., the display mounted on DISCOVERY board is 2.4" and its resolution is 240x320. 4.3" displays have usually a higher resolution, so I think something must be changed in software.

I know there are displays with embedded controllers, I'm not able to choose a suitable one.

With a "naked" TFT (RGB interface) I need a more powerful microcontroller, more RAM (most probably external to the MCU) and the PCB is more complex. But I expect the result will be better.

A TFT with an integrated controller lets me use a simpler MCU, avoid external RAM and use a simpler PCB.

Reply to
pozzugno

With emWin you can do your test on any LCD size you have. The code can be very easy ported to other display.

You can get a LPC1788 demo board with 4.3" LCD from Digikey:

formatting link

If you do not need animations, you can consider an LCD with build in display controller. Here is a 2.8" LCD board I have used for a recent small automation project:

formatting link

TFT

connect

found.

--------------------------------------- Posted through

formatting link

Reply to
armCode

Il 19/11/2014 16:31, armCode ha scritto:

Nice product, thank your for the suggestion. Even if the price is very high.

Thank you for the suggestion.

Reply to
pozzugno

Yes of course it needs to be changed to match your display. Although

4.3" displays are often of similar resolution to this I think (1/4 VGA or 1/4 WVGA).

The discovery board comes with 8MB of SDRAM for maintaining the framebuffer(s). There is also some kind of accelerator hardware for bit-blit type things. Should be able to do up to 640x480 or 800x480 say.

--

John Devereux
Reply to
John Devereux

TFTs with single LVDS interface are quite standard (connector included) and work fine with most HDMI-to-LVDS converters; actually it's quite easy to build one by using a TFP401.

--
Fletto i muscoli e sono nel vuoto.
Reply to
dalai lamah

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.