[TC-442][TC-443] Prevent mis-use of Blink_Nicla.ino sketch with Nicla Vision board

libraries/Nicla_System/examples/Blink_Nicla/Blink_Nicla.ino

@@ -1,13 +1,64 @@
-#include "Nicla_System.h"
+/*
+ Blink for Nicla Sense ME
+
+ Turns green LED on for one second, then turn it off.
+
+ Most Arduino boards have a single LED connected from D13 to ground
+ (with a current limiting resistor). In the Nicla Sense ME, the common
+ anode RGB LED (DL1) is controlled by a RGB LED Driver (U8). 
+ The RGB LED Driver state is set via I2C by the ANNA-B112 Module (MD1).
+
+ ┌────────────┐ ┌────────────┐
+ │ ANNA-B112 │ │ RGB-Driver │ VPMID
+ │ MD-1 │ │ U8 │ Red ─┬─
+ │ │ │ OUT3├────────◄──────┐ │
+ │ │ I2C │ │ Green│ │
+ │ ├──────┤ OUT2├────────◄──────┼───┘
+ │ │ │ │ Blue │
+ │ │ │ OUT1├────────◄──────┘
+ │ │ │ │
+ │ │ │ │
+ │ │ │ │
+ └────────────┘ └────────┬───┘
+ │
+ ▼
+
+ All of this is abstracted via the Nicla_System.h header file. Details
+ on use for controling RGB LED can be found at:
+ https://docs.arduino.cc/tutorials/nicla-sense-me/cheat-sheet#rgb-led
+
+ More advanced users can look at the source code at:
+ https://github.com/arduino/ArduinoCore-mbed/blob/master/libraries/Nicla_System/src/Nicla_System.h 
+
+ Authors: Giulia Cioffi, Martino Facchin & Ali Jahangiri
+
+ This example code is in the public domain.
+
+ Last edit: 2nd February 2023
+*/
+
+//This sketch is only for the Nicla Sense ME, not the Nicla Vision
+#ifdef ARDUINO_NICLA_VISION
+ #error "Run the standard Blink.ino sketch for the Nicla Vision"
+
+
+// Intialise library which communicates with RGB driver
+// Functions accessible under 'nicla' namespace
+#include "Nicla_System.h" 
+
 
 void setup() {
- nicla::begin();
- nicla::leds.begin();
+ //run this code once when Nicla Sense ME board turns on
+ nicla::begin(); // initialise library
+ nicla::leds.begin(); // Start I2C connection
 }
 
 void loop() {
- nicla::leds.setColor(green);
- delay(1000);
- nicla::leds.setColor(off);
- delay(1000);
-}
+ //run this code in a loop
+ nicla::leds.setColor(green); //turn green LED on
+ delay(1000); //wait 1 second
+ nicla::leds.setColor(off); //turn all LEDs off
+ delay(1000); //wait 1 second
+}
+
+