Hello every body,
I am using Arduino MEGA2560 and LCD 7 INCH.
I have connected the 40 pins to my Arduino board based on the attached image file.
My questions:
1- Am I connected the pins well? I think I have connected PIN RS wrong as it is "READ DATA CLOCK" and I have connected it to 3v3 positive power supply (See the picture).
2- I am using LCD, TOUCH and SD card in my project. The problem is that once I have connected the board via USB to my laptop every thing work well, but once I use external power supply I have a noise in LCD and after a short time LCD do not show anything and there are some lines in the screen (NOISE) and arduino board restart approximately each 5 sec and the LED on board blinks (Shows that board restarted). Also the Regulator on the Arduino board beacom very heat (burns your finger if you touch it). The two 25v capacitors also become heat. On Diode near these capacitors also become heat.
I try external power supply 9V 1 Amp, 9V 4 Amp and the problem remain.
I do not think my board have problem because if I disconnect the LCD every thing work well and nothing become heat on the board. I have tested other smaller board like TFT2.4" and I have no problem. The problem started when I started to use TFT 7 inch.
Please help me.
First of all, remove +5V from TFT pin 18, and also, you are aware TFT displays work on 3.3V, so you need to use translation ic's or at least inline resistors. You need translation or resistors on the following pins :-
DB0-DB15
SD_CS
MOSI
CLK
LCD_RST
LCD_WR
LCD_CS
LCD_RS
Why don't you buy a TFT shield? This is the best way to connect a TFT to the Mega.... Such as this one :- http://www.ebay.com/itm/TFT-SD-Shield-Arduino-MEGA-2560-LCD-Module-SD-level-translation-2-8-3-2-DUE-/121161179201?hash=item1c35c4e041
Regards,
Graham
Hey Graham,
Thank you for your reply and your information.
I tried using 10K resistors on the pins but display does not work well and shows noise and does not show anything else. In SSD1963 catalog also mention that do not use more than 3.3V else TFT will damage. I am using my TFT more than 1 month and it is still safe. There is also a regulator in TFT board and it shows that board work with 5V. But I do not know why it does not work with 3.3V on the pins!
I found my problem: The problem is on Arduino boards. Arduino uses a weak regulator of 5v 1A! and they recommend to use 9V power supply. See what happened if you use Arduino Mega2560 R3 with a big display like TFT 7 inch:
1- My power supply: 9V 2A.
2- Most Regulators in Arduino boards: 5V 1A.
3- TFT 7 inch (My TFT 7 inch type SSD1963) use 450mA from the Arduino board
So-> 9V - 5V = 4V; 1000mA - 450mA = 550mA; => 4V x 550mA = 2200mA*
*The problem is here: 2200mA (2.2A). Arduino has a 1A Regulator while it should be more than 2.2A if you want to use Big LCDs or TFTs.
Solution:
- Using 5V 1A(1A or more. no different) power supply which send 5.2V ~ 5.4V to the regulator on Ardiono board.
Calculation:
So-> 5.2V - 5V = 0.2V; 1000mA - 450mA = 550mA; => 0.2V x 550mA = 110mA => Regulator work well!
I see Arduino recommend using 9V 1A power supply and the range of power supply you can use is 6~12V. but in this case you can just use 5V not more or you should make your own board with a strong regulator like 5V 3A Regulator which has its component as you know.
I have another question: I AM USING UTFT LIBRARY MADE BY RINKY DINK. IS THERE ANY OTHER LIBRARY FOR WORKING TFTS. There are some problems on UTFT library and one is that you should use just fonts with width of 8, 16, 24, 32, .... But I need a font with width of 12 Pixel which UTFT does not support it. 8 is very small and 16 is very big for TFT 7".
Reagrds,
Hasan
