Using an LCD on the Edison

Contributors: Shawn Hymel

Example Program: C++

If you are used to writing C/C++, then this is the way to go. Go back to your home directory and create a C++ file:

cd ~
vi ili9341.cpp

Press 'i' to type text. Copy and paste the code below into vi (if you are using an SSH client like PuTTY, simply right-click in the window to paste).

language:cpp
#include <unistd.h>

#include "ili9341.h"

int main(int argc, char **argv) {

    // Pins (Edison)
    // CS_LCD   GP44 (MRAA 31)
    // CS_SD    GP43 (MRAA 38) unused
    // DC       GP12 (MRAA 20)
    // RESEST   GP13 (MRAA 14)
    upm::ILI9341 * lcd = new upm::ILI9341(31, 38, 20, 14);

    // Fill the screen with a solid color
    lcd->fillScreen(lcd->color565(0, 40, 16));

    // Draw some shapes
    lcd->drawFastVLine(10, 10, 100, ILI9341_RED);
    lcd->drawFastHLine(20, 10, 50, ILI9341_CYAN);
    lcd->drawLine(160, 30, 200, 60, ILI9341_GREEN);
    lcd->fillRect(20, 30, 75, 60, ILI9341_ORANGE);
    lcd->drawCircle(70, 50, 20, ILI9341_PURPLE);
    lcd->fillCircle(120, 50, 20, ILI9341_PURPLE);
    lcd->drawTriangle(50, 100, 10, 140, 90, 140, ILI9341_YELLOW);
    lcd->fillTriangle(150, 100, 110, 140, 190, 140, ILI9341_YELLOW);
    lcd->drawRoundRect(20, 150, 50, 30, 10, ILI9341_RED);
    lcd->drawRoundRect(130, 150, 50, 30, 10, ILI9341_RED);
    lcd->fillRoundRect(75, 150, 50, 30, 10, ILI9341_RED);

    // Write some text
    lcd->setCursor(0, 200);
    lcd->setTextColor(ILI9341_LIGHTGREY);
    lcd->setTextWrap(true);
    lcd->setTextSize(1);
    lcd->print("Text 1\n");
    lcd->setTextSize(2);
    lcd->print("Text 2\n");
    lcd->setTextSize(3);
    lcd->print("Text 3\n");
    lcd->setTextSize(4);
    lcd->print("Text 4\n");

    // Test screen rotation
    for(int r = 0; r < 4; r++) {
        lcd->setRotation(r);
        lcd->fillRect(0, 0, 5, 5, ILI9341_WHITE);
        sleep(1);
    }

    // Invert colors, wait, then revert back
    lcd->invertDisplay(true);
    sleep(2);
    lcd->invertDisplay(false);

    // Don't forget to free up that memory!
    delete lcd;

    return 0;
}

Save and exit ('esc', type ':wq', and press 'enter'). Append the UPM modules location to our linker PATH, and compile the program:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
g++ ili9341.cpp -o ili9341 -lupm-ili9341 -lmraa -I/usr/local/include/upm

Run the program:

./ili9341

The screen will fill with a color and draw some basic shapes!