Create ledcWrite_RGB.ino (espressif#688)

* Create ledcWrite_demo_ESP32_RGB.ino adding the public domain example ledcWrite_demo_ESP32.ino to this repo. Added RGB to the name for people searching, added some comments, and renames things to make a bit more sense. * Update ledcWrite_demo_ESP32_RGB.ino renamed to ledcWrite_RGB.ino and added a couple more comments based on espressif#689 * Rename libraries/ESP32/examples/AnalogOut/ledcWrite_demo_ESP32_RGB/ledcWrite_demo_ESP32_RGB.ino to libraries/ESP32/examples/AnalogOut/ledcWrite_RGB/ledcWrite_RGB.ino Renamed.

Author: Allan

libraries/ESP32/examples/AnalogOut/ledcWrite_RGB/ledcWrite_RGB.ino

@@ -0,0 +1,130 @@
+/*
+ ledcWrite_RGB.ino
+ Runs through the full 255 color spectrum for an rgb led 
+ Demonstrate ledcWrite functionality for driving leds with PWM on ESP32
+ 
+ This example code is in the public domain.
+ 
+ Some basic modifications were made by vseven, mostly commenting.
+ */
+ 
+// Set up the rgb led names
+uint8_t ledR = A4;
+uint8_t ledG = A5;
+uint8_t ledB = A18; 
+
+uint8_t ledArray[3] = {1, 2, 3}; // three led channels
+
+const boolean invert = true; // set true if common anode, false if common cathode
+
+uint8_t color = 0; // a value from 0 to 255 representing the hue
+uint32_t R, G, B; // the Red Green and Blue color components
+uint8_t brightness = 255; // 255 is maximum brightness, but can be changed. Might need 256 for common anode to fully turn off.
+
+// the setup routine runs once when you press reset:
+void setup() 
+{ 
+ Serial.begin(115200);
+ delay(10); 
+ 
+ ledcAttachPin(ledR, 1); // assign RGB led pins to channels
+ ledcAttachPin(ledG, 2);
+ ledcAttachPin(ledB, 3);
+ 
+ // Initialize channels 
+ // channels 0-15, resolution 1-16 bits, freq limits depend on resolution
+ // ledcSetup(uint8_t channel, uint32_t freq, uint8_t resolution_bits);
+ ledcSetup(1, 12000, 8); // 12 kHz PWM, 8-bit resolution
+ ledcSetup(2, 12000, 8);
+ ledcSetup(3, 12000, 8);
+}
+
+// void loop runs over and over again
+void loop() 
+{
+ Serial.println("Send all LEDs a 255 and wait 2 seconds.");
+ // If your RGB LED turns off instead of on here you should check if the LED is common anode or cathode.
+ // If it doesn't fully turn off and is common anode try using 256.
+ ledcWrite(1, 255);
+ ledcWrite(2, 255);
+ ledcWrite(3, 255);
+ delay(2000);
+ Serial.println("Send all LEDs a 0 and wait 2 seconds.");
+ ledcWrite(1, 0);
+ ledcWrite(2, 0);
+ ledcWrite(3, 0);
+ delay(2000);
+ 
+ Serial.println("Starting color fade loop.");
+ 
+ for (color = 0; color < 255; color++) { // Slew through the color spectrum
+
+ hueToRGB(color, brightness); // call function to convert hue to RGB
+
+ // write the RGB values to the pins
+ ledcWrite(1, R); // write red component to channel 1, etc.
+ ledcWrite(2, G); 
+ ledcWrite(3, B); 
+ 
+ delay(100); // full cycle of rgb over 256 colors takes 26 seconds
+ }
+ 
+}
+
+// Courtesy http://www.instructables.com/id/How-to-Use-an-RGB-LED/?ALLSTEPS
+// function to convert a color to its Red, Green, and Blue components.
+
+void hueToRGB(uint8_t hue, uint8_t brightness)
+{
+ uint16_t scaledHue = (hue * 6);
+ uint8_t segment = scaledHue / 256; // segment 0 to 5 around the
+ // color wheel
+ uint16_t segmentOffset =
+ scaledHue - (segment * 256); // position within the segment
+
+ uint8_t complement = 0;
+ uint16_t prev = (brightness * ( 255 - segmentOffset)) / 256;
+ uint16_t next = (brightness * segmentOffset) / 256;
+
+ if(invert)
+ {
+ brightness = 255 - brightness;
+ complement = 255;
+ prev = 255 - prev;
+ next = 255 - next;
+ }
+
+ switch(segment ) {
+ case 0: // red
+ R = brightness;
+ G = next;
+ B = complement;
+ break;
+ case 1: // yellow
+ R = prev;
+ G = brightness;
+ B = complement;
+ break;
+ case 2: // green
+ R = complement;
+ G = brightness;
+ B = next;
+ break;
+ case 3: // cyan
+ R = complement;
+ G = prev;
+ B = brightness;
+ break;
+ case 4: // blue
+ R = next;
+ G = complement;
+ B = brightness;
+ break;
+ case 5: // magenta
+ default:
+ R = brightness;
+ G = complement;
+ B = prev;
+ break;
+ }
+}