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Topic: TFT First Steps Questions (Read 276 times) previous topic - next topic

Hello,

I bought 2 screens, listed below:
http://www.aliexpress.com/snapshot/6426382178.html?orderId=65227826174470
http://www.aliexpress.com/snapshot/6422651153.html?orderId=65225167574470

Both doesn't work for some examples code, like this one:
http://tronixstuff.com/2013/04/26/tutorial-arduino-and-ili9325-colour-tft-lcd-modules/

Only thing Ive got is a white screen - from the led backlit

First of all:
If the screen is said that is 3/5V capable, can I still send data on a 5V level?

I clearly see a 3V voltage regulator (LM6206-3.0 N3) but this is only to the supply, obvuiosly not for data pins.
With a Nokia 5110 screen, I used 10Kohm resistors to lower the voltage to around 3V. Here - that doesn't work. Maybe someone know, that I should use different resistors values?

Or maybe I am just making everything wrong ? Do you have any troubleshoot tips? debugging tips?

This is my code for the 8/16 bit screen, nothing much, just an example
Code: [Select]

// UTFT_ViewFont (C)2012 Henning Karlsen
// web: http://www.henningkarlsen.com/electronics
//
// modified by John Boxall, April 2013

#include <UTFT.h>

// Declare which fonts we will be using
extern uint8_t SmallFont[];
extern uint8_t BigFont[];
extern uint8_t SevenSegNumFont[];

UTFT myGLCD(ILI9325C,19,18,17,16); 

void setup()
{
  myGLCD.InitLCD();
  myGLCD.clrScr();
}

void loop()
{
  myGLCD.setColor(255, 0, 0);
  myGLCD.setBackColor(0, 0, 0);

  myGLCD.setFont(BigFont);
  myGLCD.print(" !\"#$%&'()*+,-./", CENTER, 0);
  myGLCD.print("0123456789:;<=>?", CENTER, 16);
  myGLCD.print("@ABCDEFGHIJKLMNO", CENTER, 32);
  myGLCD.print("PQRSTUVWXYZ[\\]^_", CENTER, 48);
  myGLCD.print("`abcdefghijklmno", CENTER, 64);
  myGLCD.print("pqrstuvwxyz{|}~ ", CENTER, 80);

  myGLCD.setColor(0, 255, 0);

  myGLCD.setFont(SmallFont);
  myGLCD.print(" !\"#$%&'()*+,-./0123456789:;<=>?", CENTER, 120);
  myGLCD.print("@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_", CENTER, 132);
  myGLCD.print("`abcdefghijklmnopqrstuvwxyz{|}~ ", CENTER, 144);

  myGLCD.setColor(0, 0, 255);

  myGLCD.setFont(SevenSegNumFont);
  myGLCD.print("0123456789", CENTER, 190);
  while(1) {}; // do nothing
}



If you can help me anyhow - I'd be grateful!

Filip

HazardsMind

I dont think you can hook up those displays directly to the arduino so im pretty sure need an additional shield. 
What board are you using anyway, a mega or something else?
My GitHub:
https://github.com/AndrewMascolo?tab=repositories


HazardsMind

You need something like this HEREbut for your type of screen, so I suggest you contact your seller and ask him or her what to get.
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

This is nothing else as far as I see, but pins and between them there is a resistor - if i see well, it is 103 so 10Kohm

That tells me I should use 10kOhm also. I will search for a problems somewhere else then.

Thanks!

HazardsMind

Your display pins may only take a digital high signal of 3.3v where as the arduino outputs at 5v. 

For all pins.
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

Thanks HazardMind - if you have the knowlegde - please confirm that 10K resistors will be fine for that.

I am also thinking about this:
https://learn.adafruit.com/arduino-tips-tricks-and-techniques/3-3v-conversion

I even ordered some 3.3V regulators

HazardsMind

#7
Jan 14, 2015, 09:08 pm Last Edit: Jan 14, 2015, 09:08 pm by HazardsMind
Quote
I am also thinking about this:
https://learn.adafruit.com/arduino-tips-tricks-and-techniques/3-3v-conversion
You might want to get a second or even a third opinion before you actually do this, from other users. Maybe PaulS or AWOL, perhaps even CrossRoads. Because i am not sure what chip needs what voltage.
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

AWOL

I'd probably go for three 1k resistors for the level converter, but I'm no hardware engineer.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

HazardsMind

#9
Jan 21, 2015, 03:51 pm Last Edit: Jan 21, 2015, 05:39 pm by HazardsMind
He could also get a few of these buffer chips or similar, 74HC4050

Added:
Are there any 4 in 1 or 8 in 1 optocoupler packages? That would be much easier than tons of resistors. 
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

Guys,

I resolved my problem - partialy. First of all, instead of 10kOhm resistors, I user a voltage splitter using 150 and 220 Ohms.

After that it still didn't work - for my own sake, I tried software SPI, and it worked. I don't know why, there is completely nothing on my pin 13 output (clk), probably there is something wrong with my MCU... Will try it with another Arduino and check if it works.

Thanks for help everyone!

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