examples: add comments (#101)

Author: Hannes7eicher

libraries/AnalogWave/examples/DACEqualTemperedScale/DACEqualTemperedScale.ino

@@ -21,6 +21,9 @@
    created 18 Dec 2018
    modified 3 Jul 2023
    by Tom Igoe
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/dac
 */
 
 // include the AnalogWave library:

libraries/AnalogWave/examples/DACJacques/DACJacques.ino

@@ -1,4 +1,4 @@
-  /*
+/*
   DAC Melody player
 
   Generates a series of tones from MIDI note values
@@ -14,6 +14,9 @@ circuit:
   created 13 Feb 2017
   modified 3 Jul 2023
   by Tom Igoe
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/dac
 */
 #include "analogWave.h"
 analogWave wave(DAC);

libraries/AnalogWave/examples/SineWave/SineWave.ino

@@ -1,17 +1,30 @@
-#include "analogWave.h"
+/*
+  SineWave
 
-analogWave wave(DAC);
+  Generates a pre-generated sawtooth-waveform.
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/dac
+*/
+
+#include "analogWave.h" // Include the library for analog waveform generation
+
+analogWave wave(DAC);   // Create an instance of the analogWave class, using the DAC pin
 
 int freq = 10;  // in hertz, change accordingly
 
 void setup() {
-  Serial.begin(115200);
-  wave.sine(freq);
+  Serial.begin(115200);  // Initialize serial communication at a baud rate of 115200
+  wave.sine(freq);       // Generate a sine wave with the initial frequency
 }
 
 void loop() {
+  // Read an analog value from pin A5 and map it to a frequency range
   freq = map(analogRead(A5), 0, 1024, 0, 10000);
+
+  // Print the updated frequency to the serial monitor
   Serial.println("Frequency is now " + String(freq) + " hz");
-  wave.freq(freq);
-  delay(1000);
+
+  wave.freq(freq);  // Set the frequency of the waveform generator to the updated value
+  delay(1000);      // Delay for one second before repeating
 }

libraries/Arduino_CAN/examples/CANRead/CANRead.ino

@@ -1,3 +1,12 @@
+/*
+  CANRead
+
+  Receive and read CAN Bus messages
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/can
+*/
+
 /**************************************************************************************
  * INCLUDE
  **************************************************************************************/

libraries/Arduino_CAN/examples/CANWrite/CANWrite.ino

@@ -1,3 +1,12 @@
+/*
+  CANWrite
+
+  Write and send CAN Bus messages
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/can
+*/
+
 /**************************************************************************************
  * INCLUDE
  **************************************************************************************/

libraries/Arduino_FreeRTOS/examples/FreeRTOS-Blink/FreeRTOS-Blink.ino

@@ -1,3 +1,11 @@
+/*
+  The code demonstrates the usage of FreeRTOS (Real-Time Operating System) to run concurrent tasks.
+
+  One task is responsible for running the loop() logic (in a thread-safe manner), 
+  while the other task blinks an LED using the built-in LED on non-Portenta boards or 
+  the RGB LED on the Portenta C33 board.
+*/
+
 /**************************************************************************************
  * INCLUDE
  **************************************************************************************/

libraries/Arduino_LED_Matrix/examples/DisplaySingleFrame/DisplaySingleFrame.ino

@@ -1,21 +1,39 @@
-#include "Arduino_LED_Matrix.h"
-#include "frames.h"
+/*
+  Single Frame
+  
+  Displays single frames using matrix.loadFrame
+  
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/led-matrix
+*/
 
-ArduinoLEDMatrix matrix;
+#include "Arduino_LED_Matrix.h"   // Include the LED_Matrix library
+#include "frames.h"               // Include a header file containing frame data
+
+ArduinoLEDMatrix matrix;          // Create an instance of the ArduinoLEDMatrix class
 
 void setup() {
-  Serial.begin(115200);
-  matrix.begin();
+  Serial.begin(115200);           // Initialize serial communication at a baud rate of 115200
+  matrix.begin();                 // Initialize the LED matrix
 }
 
 void loop() {
+  // Load and display the "chip" frame on the LED matrix
   matrix.loadFrame(chip);
-  delay(500);
+  delay(500);  // Pause for 500 milliseconds (half a second)
+
+  // Load and display the "danger" frame on the LED matrix
   matrix.loadFrame(danger);
   delay(500);
+
+  // Load and display the "happy" frame on the LED matrix
   matrix.loadFrame(happy);
   delay(500);
+
+  // Load and display the "heart" frame on the LED matrix
   matrix.loadFrame(heart);
   delay(500);
+
+  // Print the current value of millis() to the serial monitor
   Serial.println(millis());
 }

libraries/Arduino_LED_Matrix/examples/GameOfLife/GameOfLife.ino

@@ -1,9 +1,19 @@
 /*
+  Game Of Life
+
+  The Game of Life, also known simply as Life, is a cellular automaton devised 
+  by the British mathematician John Horton Conway in 1970. It is a zero-player game, 
+  meaning that its evolution is determined by its initial state, requiring no further 
+  input.
+
   Example developed starting from Toby Oxborrow's sketch
   https://github.com/tobyoxborrow/gameoflife-arduino/blob/master/GameOfLife.ino
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/led-matrix
 */
 
-#include "Arduino_LED_Matrix.h"
+#include "Arduino_LED_Matrix.h" // Include the LED_Matrix library
 
 // grid dimensions. should not be larger than 8x8
 #define MAX_Y 8

libraries/Arduino_LED_Matrix/examples/LivePreview/LivePreview.ino

@@ -5,27 +5,34 @@
   The LED Matrix editor is part of Arduino Labs (https://labs.arduino.cc/), and is therefore considered experimental software.
 
   Don't forget to close any serial monitor already opened.
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/led-matrix  
 */
 
-#include "Arduino_LED_Matrix.h"
+#include "Arduino_LED_Matrix.h" // Include the LED_Matrix library
 
-ArduinoLEDMatrix matrix;
+ArduinoLEDMatrix matrix;        // Create an instance of the ArduinoLEDMatrix class
 
 void setup() {
-  Serial.begin(115200);
-  matrix.begin();
+  Serial.begin(115200);         // Initialize serial communication at a baud rate of 115200
+  matrix.begin();               // Initialize the LED matrix
 }
 
+// Define an array to hold pixel data for a single frame (4 pixels)
 uint32_t frame[] = {
   0, 0, 0, 0xFFFF
 };
 
 void loop() {
+  // Check if there are at least 12 bytes available in the serial buffer
   if(Serial.available() >= 12){
+    // Read 4 bytes from the serial buffer and compose them into a 32-bit value for each element in the frame
     frame[0] = Serial.read() | Serial.read() << 8 | Serial.read() << 16 | Serial.read() << 24;
     frame[1] = Serial.read() | Serial.read() << 8 | Serial.read() << 16 | Serial.read() << 24;
     frame[2] = Serial.read() | Serial.read() << 8 | Serial.read() << 16 | Serial.read() << 24;
+    
+     // Load and display the received frame data on the LED matrix
     matrix.loadFrame(frame);
   }
 }
-

libraries/Arduino_LED_Matrix/examples/MatrixFrameBuffer/MatrixFrameBuffer.ino

@@ -1,8 +1,23 @@
-#include "Arduino_LED_Matrix.h"
-ArduinoLEDMatrix matrix;
+/*
+  Matrix Frame Buffer
+  
+  This Arduino sketch demonstrates the creation and manipulation of 
+  a frame buffer for the LED matrix. The frame buffer is used to control 
+  the lighting of individual LEDs on the matrix, turning them randomly on and off.
+  
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/led-matrix
+*/
 
+// Include the LED_Matrix library
+#include "Arduino_LED_Matrix.h"  
+
+// Create an instance of the ArduinoLEDMatrix class
+ArduinoLEDMatrix matrix;        
+
+// Define the frame array for the LED matrix with pixel values
 uint8_t frame[8][12] = {
-  { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
+  { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }, 
   { 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0 },
   { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
   { 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0 },
@@ -12,26 +27,36 @@ uint8_t frame[8][12] = {
   { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }
 };
 
+// Set up time intervals and dimensions for the matrix
 unsigned long lastTickTime, lastGameTickTime;
 #define UPDATE_INTERVAL 100
 #define GAME_UPDATE_INTERVAL 66
 
 #define ROWS 8
 #define COLUMNS 12
 
+// Variables to track the current positions
 uint8_t pointX = 0, pointY = 0;
 
 void setup() {
-  // put your setup code here, to run once:
+  // Initialize serial communication and delaying for setup
   Serial.begin(115200);
   delay(1500);
+
+  // Initialize the LED matrix
   matrix.begin();
+
+  // Initialize time tracking variables
   lastGameTickTime = lastTickTime = millis();
 }
 
 void loop() {
+  // Track the current time
   unsigned long msNow = millis();
+
+  // Update the game logic with a fixed interval
   if (msNow - lastGameTickTime > GAME_UPDATE_INTERVAL) {
+    // Increment pointX and handling wraparound
     pointX++;
     if (pointX >= COLUMNS) {
       pointX = 0;
@@ -40,14 +65,24 @@ void loop() {
         pointY = 0;
       }
     }
+
+    // Generate random positions and pixel value
     pointX = random(COLUMNS);
     pointY = random(ROWS);
     uint8_t pixelValue = random(2);
+
+    // Update the frame with the new pixel value
     frame[pointY][pointX] = pixelValue;
+
+    // Update the last game tick time
     lastGameTickTime = msNow;
   }
+
+  // Render the LED matrix with the current frame at a fixed interval
   if (msNow - lastTickTime > UPDATE_INTERVAL) {
     matrix.renderBitmap(frame, 8, 12);
+
+    // Update the last rendering tick time
     lastTickTime = msNow;
   }
 }

libraries/Arduino_LED_Matrix/examples/MatrixIntro/MatrixIntro.ino

@@ -11,6 +11,9 @@
 
   created 26 Jun 2023
   by Martino Facchin
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/led-matrix
 */
 
 

libraries/Arduino_LED_Matrix/examples/PlayAnimation/PlayAnimation.ino

@@ -1,7 +1,19 @@
-#include "Arduino_LED_Matrix.h"
-#include "animation.h"
+/*
+  Play Animation
 
-ArduinoLEDMatrix matrix;
+  Sketch shows animation defined in animation.h
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/led-matrix
+*/
+
+
+
+#include "Arduino_LED_Matrix.h"   //Include the LED_Matrix library
+#include "animation.h"            //Include animation.h header file
+
+// Create an instance of the ArduinoLEDMatrix class
+ArduinoLEDMatrix matrix;  
 
 void setup() {
   Serial.begin(115200);

libraries/EEPROM/examples/eeprom_read/eeprom_read.ino

@@ -1,11 +1,15 @@
 /*
- * EEPROM Read
- *
- * Reads the value of each byte of the EEPROM and prints it
- * to the computer.
- * This example code is in the public domain.
+  EEPROM Read
+
+  Reads the value of each byte of the EEPROM and prints it
+  to the computer.
+  This example code is in the public domain.
+
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/eeprom
  */
 
+// Include the EEPROM library
 #include <EEPROM.h>
 
 // start reading from the first byte (address 0) of the EEPROM

libraries/EEPROM/examples/eeprom_write/eeprom_write.ino

@@ -1,11 +1,15 @@
 /*
- * EEPROM Write
- *
- * Stores values read from analog input 0 into the EEPROM.
- * These values will stay in the EEPROM when the board is
- * turned off and may be retrieved later by another sketch.
+  EEPROM Write
+  
+  Stores values read from analog input 0 into the EEPROM.
+  These values will stay in the EEPROM when the board is
+  turned off and may be retrieved later by another sketch.
+ 
+  See the full documentation here:
+  https://docs.arduino.cc/tutorials/uno-r4-wifi/eeprom
  */
 
+// Include the EEPROM library
 #include <EEPROM.h>
 
 /** the current address in the EEPROM (i.e. which byte we're going to write to next) **/

libraries/RTC/examples/RTC_Alarm/RTC_Alarm.ino

@@ -1,4 +1,6 @@
 /*
+ * RTC_Alarm
+ *
  * This example demonstrates how to use the alarm functionality of the RTC
  * (Real Time Clock) on the Portenta C33 and UNO R4 Minima / WiFi.
  *
@@ -9,12 +11,16 @@
  *
  * Note that the Portenta C33's LED is inverted and will be lit when
  * the state is 0 (LOW).
+ * 
+ * Find the full UNO R4 WiFi RTC documentation here:
+ * https://docs.arduino.cc/tutorials/uno-r4-wifi/rtc
  */
 
 unsigned long previousMillis = 0;
 const long interval = 1000;
 bool ledState = false;
 
+// Include the RTC library
 #include "RTC.h"
 
 void setup() {