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Topic: Noob TFT LCD question (Read 866 times) previous topic - next topic


Jul 27, 2015, 07:16 pm Last Edit: Jul 27, 2015, 07:18 pm by c131frdave

I'm trying to learn how to use LCD screens and I found this: http://www.banggood.com/UNO-R3-ATmega328P-Board-2_4-Inch-TFT-LCD-Screen-Module-For-Arduino-p-945755.html?utm_source=facebook&utm_medium=cpc_elc&utm_campaign=ar-r3screen-us-sm-r-all&utm_content=tracy&utm_design=27

It's an LCD touch screen shield.  It looks like it uses all of the pins though, so I'm wondering if it can be used for other outputs.  Like how would you use this shield to then send PPM to a servo or something?  How can we use these complicated LCDs and still have external functionality? 



You would need to look at the data sheet to see what pins are actually being used. The seller of that display should be able to supply you with the correct data sheet. If not then you should be able to search for it by the information either on the display itself or from what the seller described it as.
My GitHub:


Jul 27, 2015, 07:31 pm Last Edit: Jul 27, 2015, 07:33 pm by MAS3
Quote from: Seller
8 bit digital interface, plus 4 control lines
Uses digital pins 5-13 and analog 0-3. That means you can use digital pins 2, 3 and analog 4 and 5. Pin 12 is available if not using the micro SD
5V compatible, use with 3.3V or 5V logic
Not all pins are used.
So there is room to expand functions.
Best pins available are A4 and A5.
These are the I2C pins.
So you can expand functionality using up to 127 I2C devices if i remember correct.
Depending on the use of pins 10,11,12 and 13 by the display module, you might even be able to use 2 SPI devices, and given the above description i think there's a good chance for that to be true.
If you want something complicated you can even use I2C to expand the number of available SPI devices.

So there's still plenty of possible things to do with this display shield.
Have a look at "blink without delay".
Did you connect the grounds ?
Je kunt hier ook in het Nederlands terecht: http://arduino.cc/forum/index.php/board,77.0.html


Jul 27, 2015, 07:33 pm Last Edit: Jul 27, 2015, 07:37 pm by david_prentice
By the time that you have plugged in the shield,   you can not really get at any of the pins.    And most are used  by the TFT anyway.
If you do not use the microSD,   you could use A5 and D10 .. D13,  D0, D1 but you would need to be careful.

Displays that use SPI for the TFT,  touch and disk controller will leave you lots of unused pins.    But you still have the same problem of physical access to them.    You can use a stacking adapter between the Uno and the display.

I would be very sceptical about the 5-13 and A0-A3.    In real life,   these displays tend to use 2-13 and A0-A4.



Get to any pins while a display is attached: CrossRoads' Uno Screw Shield (click !) (scroll down to approximately 60 %).
You can contact hyperactive forum member CrossRoads through his mail address you'll find on the bottom of that page to see whether he has some available for sale.
Or perhaps he'll see this and react to it.
Have a look at "blink without delay".
Did you connect the grounds ?
Je kunt hier ook in het Nederlands terecht: http://arduino.cc/forum/index.php/board,77.0.html

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