Parallax LCD Terminal AppMod + Arduino

Hi Everyone,

Long time programmer in all languages, but this is my first dabble in doing anything with electronics, so please bare with me.

I just got an arduino USB and happened to have a Parallax LCD Terminal App Mod laying around, this guy:

Product page with specs at:
http://www.parallax.com/Store/Accessories/Communication/tabid/161/CategoryID/36/List/0/Level/a/ProductID/53/Default.aspx?SortField=ProductName%2CProductName

I like the concept of it as a small display with four buttons sure sounds useful for a lot of projects, the cost doesn't seem too prohibitive either. Sadly I haven't seen any examples of anyone using such a device with an arduino.

Looking at the specs, although it has the 20 pin AppMod pinout, it looks like only 7 digital pins are actually used. It uses the HD44780 controller, which if I'm correct is the typical controller for LCD's.

Anybody want to help me write a module to use this guy? Seems like it would be a useful library to have for a lot of people. Will the standard 8 and 4 bit LCD modules work?

Thanks,

-Nic

I got my Arduino today and got this working in a few hours, turns out it was pretty simple.

The parallax wdget uses 4 bit mode, so the LCD 4 Bit library works great. Only hangup was that the Parallax specification has the pinout mirrored (ie incorrect), after scratching my head as to why it kept resetting my board I reversed everything and all is well.

It's actually not a bad setup, as I got the 4 buttons working as well, they share pins with the d4-d7 pins on the LCD. (you just have to switch them to inputs while you read them)

So for 6 digital pins you get:

  • a 2x8 LCD with a build in POT
  • 4 push buttons

Ya, it's a bit pricey ($15) but I already had it, so sunk cost there.

Good little learning exercise for me as well.

If anybody is interested in a write up, I'd be glad to oblige, though judging by the lack of responses I'm the only one in the world with one of these guys.

-Nic

I have one too - if you have some code please post it.

Thanks, - Precog