Example-01_Basic.ino

/*
  Basic menu example using GEM library.

  Simple one page menu with one editable menu item associated with int variable, one with bool variable,
  and a button, pressing of which will result in int variable value printed to Serial monitor if bool variable is set to true.

  AltSerialGraphicLCD library is used to draw menu.
  KeyDetector library is used to detect push-buttons presses.
  
  Additional info (including the breadboard view) available on GitHub:
  https://github.com/Spirik/GEM
  
  This example code is in the public domain.
*/

#include <GEM.h>
#include <KeyDetector.h>

// Pins the buttons are connected to
const byte downPin = 2;
const byte leftPin = 3;
const byte rightPin = 4;
const byte upPin = 5;
const byte cancelPin = 6;
const byte okPin = 7;

// Array of Key objects that will link GEM key identifiers with dedicated pins
Key keys[] = {{GEM_KEY_UP, upPin}, {GEM_KEY_RIGHT, rightPin}, {GEM_KEY_DOWN, downPin}, {GEM_KEY_LEFT, leftPin}, {GEM_KEY_CANCEL, cancelPin}, {GEM_KEY_OK, okPin}};

// Create KeyDetector object
KeyDetector myKeyDetector(keys, sizeof(keys)/sizeof(Key));
// To account for switch bounce effect of the buttons (if occur) you may want to specify debounceDelay
// as the third argument to KeyDetector constructor:
// KeyDetector myKeyDetector(keys, sizeof(keys)/sizeof(Key), /* debounceDelay= */ 10);

// Constants for the pins SparkFun Graphic LCD Serial Backpack is connected to and SoftwareSerial object
const byte rxPin = 8;
const byte txPin = 9;
SoftwareSerial serialLCD(rxPin, txPin);

// Create an instance of the GLCD class. This instance is used to call all the subsequent GLCD functions
// (internally from GEM library, or manually in your sketch if it is required)
GLCD glcd(serialLCD);

// Create variables that will be editable through the menu and assign them initial values
int number = -512;
bool enablePrint = false;

// Create two menu item objects of class GEMItem, linked to number and enablePrint variables 
GEMItem menuItemInt("Number:", number);
GEMItem menuItemBool("Enable print:", enablePrint);

// Create menu button that will trigger printData() function. It will print value of our number variable
// to Serial monitor if enablePrint is true. We will write (define) this function later. However, we should
// forward-declare it in order to pass to GEMItem constructor
void printData(); // Forward declaration
GEMItem menuItemButton("Print", printData);

// Create menu page object of class GEMPage. Menu page holds menu items (GEMItem) and represents menu level.
// Menu can have multiple menu pages (linked to each other) with multiple menu items each
GEMPage menuPageMain("Main Menu");

// Create menu object of class GEM. Supply its constructor with reference to glcd object we created earlier
GEM menu(glcd);
// Which is equivalent to the following call (you can adjust parameters to better fit your screen if necessary):
// GEM menu(glcd, /* menuPointerType= */ GEM_POINTER_ROW, /* menuItemsPerScreen= */ 5, /* menuItemHeight= */ 10, /* menuPageScreenTopOffset= */ 10, /* menuValuesLeftOffset= */ 86);

void setup() {
  // Push-buttons pin modes
  pinMode(downPin, INPUT);
  pinMode(leftPin, INPUT);
  pinMode(rightPin, INPUT);
  pinMode(upPin, INPUT);
  pinMode(cancelPin, INPUT);
  pinMode(okPin, INPUT);

  // Serial communications setup
  Serial.begin(115200);
  serialLCD.begin(115200);

  // LCD reset
  delay(500);
  glcd.reset();
  delay(1000);
  // Uncomment the following lines in dire situations
  // (e.g. when screen becomes unresponsive after shutdown)
  glcd.reset();
  delay(1000);

  // Menu init, setup and draw
  menu.init();
  setupMenu();
  menu.drawMenu();
}

void setupMenu() {
  // Add menu items to menu page
  menuPageMain.addMenuItem(menuItemInt);
  menuPageMain.addMenuItem(menuItemBool);
  menuPageMain.addMenuItem(menuItemButton);

  // Add menu page to menu and set it as current
  menu.setMenuPageCurrent(menuPageMain);
}

void loop() {
  // If menu is ready to accept button press...
  if (menu.readyForKey()) {
    // ...detect key press using KeyDetector library
    myKeyDetector.detect();
    // Pass pressed button to menu
    // (pressed button ID is stored in trigger property of KeyDetector object)
    menu.registerKeyPress(myKeyDetector.trigger);
  }
}

void printData() {
  // If enablePrint flag is set to true (checkbox on screen is checked)...
  if (enablePrint) {
    // ...print the number to Serial
    Serial.print("Number is: ");
    Serial.println(number);
  } else {
    Serial.println("Printing is disabled, sorry:(");
  }
}