I recentelly bought a cheap LCD Display (JHD202A/C, 2x20 blue, for $13) that I want to hook up to my Arduino (diecimila), hopefully through a Shift register.There's a bit "background history" here. If it's to much, skip it..
On the website, from where I ordered it (http://www.electrokit.se/opto-display-lcd-lcd-2x20-tecken-jhd202a-stn-bla-vit-led_41003002
[Swedish]), the part ID is said to be JHD202A
, and the same is printed on the bag in which I got it.
BUT on the back of the display it says JHD202C
.. Fine, I thought that it's probably a revision of the component, no big deal..
I Googled JHD202C to find a datasheet but found nothing (Just some sites mentioning it, no datasheets, not even on JHDs site). Then I googled JHD202A and found some datasheet (among others I found one at the site where I bought the LCD, for a yellow/green LCD.
So I set out to connect my LCD to my arduino, I soldiered on pins in the "pin-holes" on the LCD to make it easier to connect to the arduino (and I checked the pins for shortcuts etc)..
The plan is to use an IDE-cable (http://upload.wikimedia.org/wikipedia/commons/6/61/IDE_cable_40_pin_%26_80_pin.jpg
) to connect the LCD, buttons Rotary encoders etc to the arduino. (I checked it for continuity...).
I looked up different tutorials on how to connect it to the arduino:http://www.arduino.cc/en/Tutorial/LiquidCrystalhttp://www.hacktronics.com/Tutorials/arduino-character-lcd-tutorial.html
(This last one is the one I used, as it connects the backlight, but with a trimpot instead of a fixed resistor for contrast)
The pins used matches the ones in the datasheet, and as far I gathered it is compatible with HD44780, so I hooked it up.
BUT it didn't work and the backlight wasn't lit.
As I use pin 13 for backlight and the built-in LED of the arduino was lit I started with "debugging" the backlight and disconnected all other pins. I used my multimeter to make sure (again) that the holes of the IDE-cable match etc.
Just to be sure, I switched the pins (So if pin 15 was connected to pin 13 on the arduino and 16 to ground, 15 was now connected to ground and 16 to pin 13) and voila, it lit uplEnd of background/"gibberish"
So if we look at the datasheet (http://www.electrokit.se/download/JHD202A%20SERIES.pdf
) we need to "reverse" pin 15 (to LED-) and pin 16 (to LED+). So now I'm a little confused, so I need some advice:
Should i "reverse" (odd to even, even to odd: 1 <-> 2) the rest of the pins, or is it more likely that it's just the LEDs??
What can happen if I reverse the pins? Can I destroy the LCD (or the controllers on it)?
Any ideas are highly welcome (and if you want, semo tips for using a shift register with the LCD)
(Sorry for any grammatic errors etc, but it's now 03.20AM and my brain is beginning to shut down...)