Arduino API

The reference

C Language

very good summary of the C language


Reference for the standard C API (libc): To use with Arduino, add the appropriate #include to the top of your sketch and use the functions as documented in the manual.

Bit Math Tutorial

Learn how to decipher all those cryptic formulas you see in C code that use symbols like &= and <<. Start using bitwise operators in your own code to save memory and perform sophisticated low-level operations on your microcontroller hardware.

Port Manipulation

More explanation of ports and manipulating them with bitwise operators.
Port Manipulation