Show Posts
Pages: [1]
1  Using Arduino / Displays / Re: Can't get the Displaytech 204A-CC-BC-3LP working on: November 14, 2012, 09:18:02 pm
Thank you for the input, but the wiring is identical to the photo I posted earlier when the LCD wasn't working. Maybe a dodgy breadboard?
2  Using Arduino / Displays / Re: Can't get the Displaytech 204A-CC-BC-3LP working on: November 14, 2012, 09:03:04 pm
Well, I reversed the LCD pin order, and it didn't respond at all (not even the blocks appeared). I imagine it had to of been the correct orientation originally as otherwise the contrast adjustments wouldn't have been working.

However, believe it or not, after turning the LCD back around to its original position, "Hello world" magically appeared!!! Apart from a few missing dots in the first character (which presumably must be a hardware fault), I have a working LCD!

Thank you again for the help. I don't think I will ever know why it decided to work!
3  Using Arduino / Displays / Re: Can't get the Displaytech 204A-CC-BC-3LP working on: November 14, 2012, 07:26:22 pm
My obsessive neatness is rarely a good thing, but hopefully it helped you understand the wiring on the breadboard! I have checked the connections from the arduino pins to each pad on the LCD and they all seem to be good. I had already tried using the LCD in 4-bit mode, and unfortunately it didn't work the second time around either. The sketch without the delay() and clear() yields the same response. Maybe it is time to get another LCD and test my current circuit with that... Thank you anyway!
4  Using Arduino / Displays / Re: Can't get the Displaytech 204A-CC-BC-3LP working on: November 14, 2012, 06:06:35 am
One more thing...

I am now failing to initialise the LCD. I have included a photo of my setup and have checked all pin connections and as far as I can tell they are all OK. The single line of black boxes at the top of the LCD never change. The datasheet for the LCD can be found here: http://www.displaytech.com.hk/upload/product/attachment/5287-202B.pdf (page 7).

My sketch is as follows:

Code:
/* LiquidCrystal(rs, enable, d0, d1, d2, d3, d4, d5, d6, d7) */
LiquidCrystal lcd(3,4,5,6,7,8,9,10,11,12);

void setup()
{
  delay(100);
  lcd.begin(20,2);
  lcd.clear();
  lcd.print("Hello world");
}

void loop() {}


Any help would again be very much appreciated.

Thanks.




5  Using Arduino / Displays / Re: Can't get the Displaytech 204A-CC-BC-3LP working on: November 14, 2012, 04:18:00 am
Don - thank you very much. Your second post was exactly right - I maybe should have noticed the tiny numbers on the datasheet but it certainly wasn't obvious for me! All sorted now.

Cheers.
6  Using Arduino / Displays / Re: Can't get the Displaytech 204A-CC-BC-3LP working on: November 13, 2012, 05:56:55 pm
I am having the same problem with the 202B DisplayTech LCD (202B-GC-BC-3LP). I have checked all of the supply voltages and they all seem acceptable according to the data sheet.


Parameter                                  Symbol        Condition      Min    Typ    Max    Unit
Supply voltage for logic                 VDD               ---           4.5     5.0    5.5      V
Supply current for logic                 IDD                ---           ---     0.92     3      mA
Operating voltage for LCD             VDD - VO        25°C        4.5     4.8    5.1      V
Supply voltage for LED Backlight     VF                                ---      3.4    3.5      V


The following connections are made from the LCD:


Pin 1 (Vss) -> GND
Pin 2 (Vdd) -> 5V
Pin 3 (Vo) -> Wiper of 10k potentiometer connected between 5V and GND
Pin 4 (RS) -> Arduino pin 11
Pin 5 (R/W) -> GND
Pin 6 (E) -> Arduino pin 12
Pin 15 -> 150 ohm resistor -> 5V (backlight is visible and within tolerances)
Pin 16 -> GND


I am aware that I haven't yet connected the data lines; most tutorials say that by now I should be able to get one line of black boxes on the 20x2 LCD by varying the contrast. Since the minimum  operating voltage for the LCD is (VDD - Vo), and VDD = 5V, VO must be less than 0.5V. Varying the voltage between 0V and 5V however does not produce anything on the screen (nor does varying Vo beyond 0.5V).

Have I missed something crucial? Any help would be very much appreciated as I have now spend the whole afternoon trying to get any sign of life from the LCD! (excluding the backlight).

Thanks in advance.
Pages: [1]