Added debug settings section

README.md

@@ -29,6 +29,18 @@ There are also optional settings to clear the LEDs on reset, configure a dedicat
 
 Upload to your Arduino and use a corresponding PC application to stream color data. You can get the Processing files from the [main Adalight repository](https://github.com/adafruit/Adalight), though I would recommend using [Patrick Siegler's](https://github.com/psieg/) fork of Lightpacks's Prismatik, which you can find [here](https://github.com/psieg/Lightpack/releases).
 
+## Debug Settings
+
+The code includes two debugging options:
+- DEBUG_LED
+- DEBUG_FPS
+
+`DEBUG_LED` will turn on the Arduino's built-in LED on a successful header match, and off when the LEDs latch. If your LEDs aren't working, this will help confirm that the Arduino is receiving properly formatted serial data.
+
+`DEBUG_FPS`, similarly, will toggle a given pin when the LEDs latch. This is useful for measuring framerate with external hardware, like a logic analyzer.
+
+To enable either of these settings, uncomment their respective '#define' lines.
+
 ## Issues and LED-types
 
 I've only tested the code with the WS2812B strips I have on hand, but so far it performs flawlessly. If you find an issue with the code or can confirm that it works with another chipset, please let me know!