Add example for 4*40 LCDs

Signed-off-by: Patrick Roncagliolo <[email protected]>

examples/LargeLcd_4x40/LargeLcd_4x40.ino

@@ -0,0 +1,68 @@
+#include <LiquidCrystal.h>  // Redundant, multilcd.h itself includes this header.
+#include <multilcd.h>       // This is needed
+
+void setup() {
+// For this example, we're using a 40*4 LCD. Those large LCDs have two controllers,
+// each controlling a 40*2 portion of the LCD. So, we have shared pins, except the
+// traditional EN (enable) that is usually replaced by two pins (E0 and E1): they
+// are the enable pins, one per controller.
+// We instantiate two LiquidCrystal objects, each representing a LCD controller.
+
+//       D7 to D0 ----------|--|--|--|--|--|--|--|
+//          E0/E1 -------|  |  |  |  |  |  |  |  |
+//             RS ---|   |  |  |  |  |  |  |  |  |
+//                   |   |  |  |  |  |  |  |  |  |
+  LiquidCrystal l1 (13, 10, 9, 8, 7, 6, 5, 4, 3, 2);
+  LiquidCrystal l2 (13, 11, 9, 8, 7, 6, 5, 4, 3, 2);
+
+// Create a MultiLcd instance. No parameters are required.
+  MultiLcd my440;
+
+// A bit of theory:
+// MultiLcd can handle a generic matrix of phisical LCDs or logical LCDs (controllers).
+// Each LiquidCrystal instance, once attached to a MultiLcd, is identified by an index: 0, 1, eccetera. 
+// The matrix is filled from the virtual top-left corner to the bottom-right one, from left to right, 
+// from the top to bottom, so using the occidental reading conventions.
+// Now, the practice: 
+// the 4*40 LCD is a matrix of 1 column and 2 rows. We attach the LiquidCrystal instances in this order: 
+// first the one controlling the two upper LCD lines, then the second one.
+
+// Assign the LiquidCrystal instances to the MultiLcd instance.
+  my440.attach(l1);
+  my440.attach(l2);
+
+// Use the special .begin method.
+// First two parameters are the same of the LiquidCrystal.begin() method: consider a single LCD and
+// write the number of columns, then number of rows. In this example, we have 40 columns and 2 rows.
+// Then, the new two parameters: those describe the shape of the matrix. In this example, as discussed
+// above, we have 1 column, 2 rows.
+  my440.begin(40, 2, 1, 2);
+
+// Now you can use the MultiLcd instance as a normal LiquidCrystal object.
+  my440.blink();
+  my440.cursor();
+  my440.home();
+  my440.print(0);
+  delay(1000);
+  my440.setCursor(39,0);
+  my440.print(0);
+  delay(1000);
+  my440.setCursor(39,3);
+  my440.print(0);
+  delay(1000);
+  my440.setCursor(0,3);
+  my440.print(0);
+  delay(1000);
+  my440.setCursor(16,0);
+  my440.print("Hello");
+  my440.setCursor(16,1);
+  my440.print("World");
+  my440.setCursor(16,2);
+  my440.print("with");
+  my440.setCursor(16,3);
+  my440.print("MultiLcd!");
+  delay(1000);
+}
+
+void loop(){
+}