How do I convert code between Arduino platforms?

Question

What documentation is available regarding the differences between the different Arduino platforms?

For example, I have some code written for an Arduino Teensy that I would like to run on an Arduino Mega.

Is there documentation on the capabilities and equivalencies between each of the platforms? e.g. memory, number of PWM outputs, etc?

Answer 1

The most detailed one seems to be Baldengineer's, but Arduino, SparkFun, and Adafruit have their own as well, although more limited.

As always, the best source for information about them is the datasheets for both the MCU(s) used as well as for the boards themselves.

And note that different macros are predefined for each MCU and feature (e.g. __AVR_ATmega328__ and __AVR_HAVE_MUL__); it is possible to test for their existence in order to customize behavior.