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Which touchscreen do you recommend? — Parallax Forums

Which touchscreen do you recommend?

PepzPepz Posts: 20
edited 2012-11-05 13:31 in Propeller 1
I'm building a Propeller project where a 3.5 inch touchscreen is wanted.
The application will draw some buttons "Start", "Stop", Enter values "0-9" and show some results.
Speed is NOT an issue, well <1sec to draw a new screen is ok.

I have a couple of these:
ET035009DH6
http://www.m-comp.dk/files/files/ET035009DH6-ROHS%20ver%201%20-%203.5%20inch%20320%20x%20240%20TP.pdf

or should i use another one?

I guess that I will use the SPI input to save pins?
This is my first "TouchScreen" project so I would prefer a screen that is proven to work fine
and has some examples how to interface it. And is dirt cheap of course!!! ;)

Thoughts?

Comments

  • RaymanRayman Posts: 14,670
    edited 2012-11-05 07:07
    That looks very similar to the PTP2 display here at Rayslogic.com.

    The PTP2 may give you some ideas on how to wire it up...
  • PepzPepz Posts: 20
    edited 2012-11-05 08:37
    Dumb question, but do I need a breakout board?
    What is the function of the breakout board?
    Is it impossible to communicate directly through the SPI to the screen
    or are all the IO circuits sitting on the breakout board?
    Can the propeller board simulate the breakout board or are there too many
    pins to toggle?
  • wjsteelewjsteele Posts: 697
    edited 2012-11-05 08:47
    Yep, you do need the breakout board as the interface is not SPI (it's more like a glorified VGA) and there is a lot going on that the propeller has to do to drive the display and process the touch input. Ray's boards and software work like champs. (The breakouts actually map the prop pins to the appropriate display pins as well as implement the touch screen controller and power supply logic.)

    Bill
  • Mark_TMark_T Posts: 1,981
    edited 2012-11-05 13:09
    There are touchscreens that size with framebuffers if you want to use fewer pins - framebuffer displays usually support 16-bit and 8-bit parallel as well as SPI interfaces. the latter allowing fewer pins and cogs to interface to. For instance this: http://www.ebay.com/itm/3-5-TFT-LCD-Module-Display-Touch-Panel-PCB-adapter-/200401013928?pt=LH_DefaultDomain_0&hash=item2ea8d4cca8
  • RaymanRayman Posts: 14,670
    edited 2012-11-05 13:31
    As Mark_T points out, you can get screens with controller boards (Rayslogic.com, has SSD1963 solutions for 4.3" and 5" screens).
    Using a more direct connection, like PTP2 and NH4, has a lot of advantages though...
    First, the code is very simple and you can get something working very quickly because it works the same way as the native VGA driver.
    Second, you can update the screen very quickly.

    But, showing photos is a bit of a problem. You can kinda show a photo with PTP2, but it would be a lot easier and better for a display with a controller chip...
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