Soldering an LCD directly to Espruino

Sometimes you might want to make a very small device with an LCD display. Using the row of pins along the middle of Espruino, you can easily do this!

The PCD8544 LCD uses so little power that it can easily be powered directly from GPIO lines - requiring no special wiring other that the swapping of two signal wires.

You'll Need

• One Espruino Board
• A PCD8544 LCD Display and some pin strip (this should come with it)

Wiring Up

• First, take the LCD display and solder pin strip onto the top row of connectors (the ones by the large bar of silver)
• Then pull off the black plastic bar that hold the pin strip together

• Carefully twist the pins for DC and DIN so that they are swapped over (but not shorting). I'd suggest doing this in stages, bending each pin at 45 degrees first, and then making another bend. then another.

• Solder the LCD display to the rear of the board, ensuring that the CLK pin is connected to A5, and the bent DIN pin is now connected to A7.

Note: If you want to fit the LCD the other way around, you could insert the pin strip into the bottom row of pins and can then place the LCD on the opposite side of the board.

The LCD should now be connected as follows:

LCD pin	Pin type	Example pin on Espruino Board
GND	GND	A2
LIGHT	Any	A3
VCC	3.3v	A4
CLK	SPI SCK	A5
DIN	SPI MOSI	A7
DC	Any	A6
CE	Any	B0
RST	Any	B1

Software

Because the display is now powered directly from Espruino's GPIO pins, they must be set correctly in order to power the LCD. Otherwise, initialisation happens just as before:

A2.write(0); // GND
// A3.write(1); // light on
A4.write(1); // VCC
SPI1.setup({ baud: 1000000, sck:A5, mosi:A7 });

var g;

function onInit() {
  setTimeout(function() {
    g = require("PCD8544").connect(SPI1,A6,B0,B1, function() {
      g.clear();
      g.drawString("Hello",0,0);
      g.drawLine(0,10,84,10);
      g.flip();
    });
  }, 200);
}

onInit();