Tuesday, December 3, 2013


I've come up with a name for the LCD backpack Arduino clone. I call it LCDuino. Yes, the Arduino FAQ talks about how lame Italians think that <mumble>uino names sound, but I'm not Italian.

The board is turning out to be a bitch to route. I'm going to have to add a couple dozen more vias before I'm done.

I do, however, have an initial layout for the DIP header. It's going to be a 32 pin .1" DIP header. The intent is that on one end of a 32 pin ribbon cable you'll crimp a standard 2 row IDC socket, and on the other you'll crimp a .3" or .5" IDC DIP plug, which you will, in turn, plug into a breadboard.

Down one side of the header will be D0 through D13, then +5 and GND. Down the other side will be the 6 pushbutton pins from the MC23017 (yes, you get 6. I'm calling the last one "BACK". Why not?), the two i2c bus pins, then A0-A3 and A6 & A7 (A4 and A5 are actually the i2c bus. A6 and A7 are not normally available on an Arduino, but the TQFP ATMega variant adds them), AREF and !RESET.

The board will come with a select button and a reset button on the board, plus a 16 MHz crystal to make it Uno compatible. It'll also come with the 2.1mm barrel jack and a 5 volt regulator. It'll be good for a couple hundred mA in addition to the LCD, backlight and controller load, but more than that and you're on your own.

The board, at present, does have an ISP socket on it, but there's nothing to stop you from programming it by wiring your own ISP to +5, GND, D11-13 and !RESET on your breadboard instead.

So why bother?

Arduino shields just don't lend themselves to breadboarding. Yes, there's a breadboard shield, but if you  then stack the LCD shield on top of it, then you've effectively built the breadboard into a sarcophagus, making it a pain to adjust the circuit. The best I've been able to do with an Uno is use pin clips between shields to bring the signals off to a breadboard on the side. That works… but this will work better.

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