Embedded Display Options

Hi All, I am a newbie in the embedded world and am looking for the best way to include a display in my embedded project.

I want to include a color touch screen with a GUI. I'm OK with coding the GUI from ground-up if need be, but I want some kind of controller because my roots are in software and not hardware. Driving a color LCD looks enormously complex.

I have a few questions that I'm hoping you'd be able to help me with:

  1. Do most embedded developers go with VGA-based systems for these kinds of displays?
  2. Are there any good places to buy embedded touch screens with controllers? I keep finding sites that sell graphical LCD panels with no controllers.
  3. Do you have any recommendations for low-end color graphical touch screens?

Thanks in advance for any help you can give!

Steve

Reply to
svrusso1
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Ok, Steve, I am an analog guy but since there are no other answers yet here is what I saw at clients: Believe it or not but most used a setup where the display and touch screen were addressed via two separate RS232 ports. Typically the display had enough smarts to load a GUI and after that it was only short commands like "highlight this button", "gray-out that button" or "advance the bar graph over there by three notches". Loading the GUI always took a while but that was done while the rest of the system had to go through the power-on reset sequence anyway.

Don't remember but they usually bought them at small distributors that specialized in touch-screen displays. Unless you can go high volume custom this is going to be surprisingly expensive. Sometimes I though "Man, I could almost buy a whole laptop for that".

I'll leave that to others, it's been too long ago.

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Here is one users approach that may work for you.

this is to do with:

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and
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Don...

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Don McKenzie
E-Mail Contact Page:               http://www.dontronics.com/e-mail.html
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Reply to
Don McKenzie

Hi guys,

Thanks for your replies!

Joerg - I have seen some displays that were controlled by RS-232, but I figured those were for hooking up to a computer. Do you have to adjust the voltage levels (i.e. with a MAX232) in order to communicate with a serial GLCD?

My biggest concern is that I want to use a method that a lot of other embedded designers use, so I could find information on it in case I run into trouble. I assumed the method would use SPI or I2C to communicate with the controller, but RS-232 is fine if that's an often-used approach.

I was unsure about VGA and RS-232 options, as I always thought they were meant for interfacing to a computer and not for embedded systems. Is that true?

I'll be using a Xilinx Spartan 3E FPGA with a soft core as my processor, if this makes any difference.

Don - Those are nice little screens, and I had seen this before:

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However they are a little small and don't have touch capability.

That's exacly what I was thinking about, though, and if I could find something a little larger (i.e. 4"; at least 320x200 resolution) and with touch capability.

Have you seen anything like that?

Thanks again!! Steve

D> > Hi All,

Reply to
svrusso1

I have one from

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for a project but haven't had a chance to work with it yet much. The built in demo is slick, and I think it will work well once I figure out what wasn't working with the serial interface. What they offer is a kit with the screen and a board they ake that runs the screen and touch and talks to your embedded controllor (or PC mockup) via a single RS232 port.

While nominally overcomplex, RS232 is quite common in the embedded world, for communication between modules and also to PCs - probably because it's very usefull to substitute a PC at any point in the system when testing. Occasionally people use 5v versions instead of the higher voltage levels, but generally the real RS232 voltages are used at least between boards.

Odd choice unless you need custom peripherals or just want to play and had it on hand. But it should work - you can graft a serial port into the FPGA no problem. Many FPGA development boards already have the level translators too (though you might need a second channel if you had planned to use that to interact with a PC).

Reply to
cs_posting

Not at that size with a touch screen Steve, someone may be aware of something along those lines. good luck.

Don...

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Don McKenzie
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Reply to
Don McKenzie

If you want to buy a chip and put it on a board, there are not many options left. The b69030 was a fine chip (still is by todays standards), they no longer make it, though. Silicon Motion

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still make some and that's all I know of - except for those made for laptops, but they are kept secret by the wintel-PC industry club. If you want to plug a PCI card into a PC and connect the TFT to it, I have seen some, could look a bit harder if you don't locate any at say Digikey, Farnell etc.

Dimiter

------------------------------------------------------ Dimiter Popoff Transgalactic Instruments

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snipped-for-privacy@gmail.com wrote:

Reply to
Didi

I didn't - i used a TTL interface but my processor has a built in controller. External controllers are numerous and not too bad to work with. If you buy a GUI (I bought emWin from Segger) then there may well be drivers to suit your controller - select one that they have drivers for to guarantee this.

If you are using a single board computer then most will give either VGA or LVDS output but several are avaible with TTL output. I think TTL screens are probably cheaper but there's not much in it.

Where are you? I know some leads in the UK.

Definitely go with resistive for the technology. I started out with capacitive and got badly burned on the reliability. They are not too hard to drive directly with an ADC and some support but there are several off-the-shelf controllers out there which you can use. The Hampshire Company make a good (so I've heard) chip that gives an RS232 output and apparently their support is excellent.

Reply to
Tom Lucas

Do you really need color?

If not, something like this would be fairly easy to use:

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Mit freundlichen Grüßen

Frank-Christian Krügel

Reply to
Frank-Christian Kruegel

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Randy Haas

Reply to
randallchaas

Hi Dimiter,

Thanks but I'm not that sophisticated, though I wish I was. Most controller chips seem to have a very small form factor, and I have no way of creating a PCB with small enough tracks to hold one, never mind the circuit design and soldering.

I'm looking more for a packaged solution.

Steve

Didi wrote:

Reply to
svrusso1

I thought that I2C or SPI would have been the way to go, but it sounds here like a lot of folks use RS232 or VGA so I am a little more comfortable with that now.

I'm in Northern NJ, US, unfortunately. In my travels I have seen a lot of web sites for electronics in the UK though-- electronics seems like a very popular hobby there. I think I must have some British blood because I am such a tinkerer.

I saw this web site recently and thought that this might be an option:

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i.e. controlling an LCD with a FPGA. One of the biggest concerns for me, as an individual hobbyist is the cost of the development. I have some great ideas for some embedded products, but my "development budget" is severely limited by my wife! So I'm trying to find the least expensive solutions with the most options, even if that means more work for me in the end.

Thanks again for the tips!

Steve

Reply to
svrusso1

Hi Frank,

That looks like a really nice module but I was really hoping to get a color screen. I will definitely consider it if I run out of options!

Thanks!

Steve

Frank-Christian Kruegel wrote:

Reply to
svrusso1

Hi Randy,

I did see the ezLCD and I was seriously considering it. Do you have any experience with these? How flexible is the GUI?

Steve

snipped-for-privacy@sbcglobal.net wrote:

Reply to
svrusso1

These Reachtech screens look really nice. I'm definitely considering these, thanks.

That is very good to know -- thank you!

In the end, I'm aware that I'll probably settle for a small form-factor PC (like

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but as I plan to run uCLinux I should be able to do so both the soft processor and the PC without too big of a hassle in software recompilation. I wanted to experiment a bit with embedded Java as well
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so this gives me the option to do that.

Reply to
svrusso1

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