OK now that we are diagrammed out, I took the protoshield and soldered 2 7-pin headers at one end of the pcb. Note that they are not all the way to the edge, I left one row of holes so I could easily solder some wires. I also soldered a short piece of header (that comes with the shield kit) at the left so that the LCD will be propped up.
You can now do a test fit to verify how it will look. it hangs over a bit but thats OK by me.
Wiring the LCD
Since this is a parallel LCD, data will be sent to it over a parallel interface. That is, multiple bits at a time. These LCDs are designed for either a 8-bit or 4-bit interface. Since we'd like to save pins, lets go with the 4-bit interface! The data pins are name D4, D5, D6, and D7. Double-check your datasheet but almost all parallel LCDs have these pins numbered 4, 3, 2, and 1 respectively.| 1 (D7) | 2 (D6) |
|---|---|
| 3 (D5) | 4 (D4) |
| 5 | 6 |
| 7 | 8 |
| 9 (ENABLE) | 10 (R/W) |
| 11 (RS) | 12 (CONTRAST) |
| 13 (GND/VSS) | 14 (+5V/VDD) |
There's a lot of wiring to be done but we're going to go thru it very slowly so it shouldn't be too bad.
Lets connect these to the arduino thusly: D4 -> Arduino pin #7, D5 -> Arduino pin #8, D6 -> Arduino pin #9, D7 -> Arduino pin #10.
Since I wasnt sure of the wiring, I used the sockets on the protoshield. Once I test and verify they are correct, I'll solder them in!
Next are the two power wires. Parallel LCDs run off of +5V so you can just solder the Vcc wire to 5V and the ground wire to GND.
Theres another control line called R/W that you can use to control whether you're reading or writing to the LCD. Since we'll just be writing, that pin can be connected to ground, saving another arduino pin.
The last wire is the contrast control, we need to connect a potentiometer to this to make the display visible. I dont know the specifics of the input current but I used a 10K potentiometer and it worked great.
One pin is connected to +5V, the pin on the other side is connected to ground and the middle pin is connected to the contrast line.
Make sure you finish up the rest of the shield so you can plug it into an arduino. At least solder in the male headers.
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