Wire up LCD with RFduino

Hi,

So I have successfully wired up a LCD like so (http://arduino.cc/en/uploads/Tutorial/LCD_bb.png) on my UNO, and I recently bought a RFduino and wanted to do the same. The problem is the RFduino only gives out 3.3v and isn't enough to power the screen.

I hooked up a 9V battery through a voltage regulator so that I have 5v to power the screen but when I run it all I just get square blocks on the screen instead of the text in the source code on the RFduino (same source as UNO + all the pins are wired the same).

Do you think it's likely I've just wired something up wrong or do you think it's a issue caused by powering the screen separately to the arduino?

Thanks

I know nothing about the RFduino, but if it's 3.3VDC, that means all the IO pins are 3.3VDC. It's not enough to power the screen with a separate 5V line: the IO pins won't be driving the LCD controller at the 5V levels it expects.

Ah, that would explain the odd behaviour. Do you think there is anyway I could step up the voltage?

I guess if I were to buy something like this: https://www.sparkfun.com/products/9054 I would be OK?

Never tried one, but that looks like a reasonable idea to me.

edit: i just checked the datasheet on the hd44780 and it says it'll work from 2.7V - 5.5V. So maybe your current display should be working?

when you powered the lcd separately, did you have a common ground?

Hi, yes I did try having a common ground. Mine's actually a 20x4 display with the same pin layout as this, but I don't have a datasheet for it. I've not dealt with these many times before so no idea if it would be the same. Mine reads on the back "TC2004A-01". And yes, it's quite an old one - might be time to buy a new one anyway :D

johnaero: Hi, yes I did try having a common ground. Mine's actually a 20x4 display with the same pin layout as this, but I don't have a datasheet for it. I've not dealt with these many times before so no idea if it would be the same. Mine reads on the back "TC2004A-01". And yes, it's quite an old one - might be time to buy a new one anyway :D

Really?? Google is your friend.

http://www.adafruit.com/datasheets/TC2004A-01.pdf

The controller is an splc780d.

I found that link earlier but the download kept timing out. Thanks though, just downloaded it.