How do I see underlying code and definitions inside Arduino IDE on MacOS X El Capitan I'm a newbie to Arduino so please excuse the easy question and guide me to the appropriate sources or forums.  I just bought an Arduino Uno Starter Kit that comes with the "Arduino Projects Book" by Scott Fitzgerald et al and I'm happily working my way through the projects.  I downloaded the Arduino IDE (version 1.7.10) onto my mac and am turning on lights, etc.  However, I'd like to see the underlying code.  For example, I use the code "digitalWrite" to turn off/on LEDs.  I'd like to see the code for this.  I can imagine that it's just a write of 1 or 0 to a particular memory address, but I'd still like to see it.  I was hoping there was a right-click->"Go To Definition", but I don't see it. I downloaded the Arduino IDE to my Downloads folder and run it just from there. It's called Arduino.app.   I don't see a folder with .c and .h files as suggested in this post:  Arduino IDE, Underlying Code and Libraries  Maybe I'm missing them?

Also, is it possible to set a breakpoint?

Again, sorry if these are "obvious" questions.  And I did look at the Arduino site without any success.

Thanks,

Dave
The simplest way is to look at the source on Github:


https://github.com/arduino/Arduino/tree/master/hardware/arduino/avr/cores/arduino


Can you set a breakpoint? No. The Arduino IDE and the bootloader don't support such functionality. To do that you need a real IDE (like Atmel Studio) and a hardware debugger.