Callback Function

Callback function is a function that runs independently of the main program routine and is automatically executed at fixed intervals.  Therefore, a callback function cannot include code that requires much time.  Use of loops, variables, and function calls are limited.  

Usage

• The callback function cannot exist inside another function or program body.
• There can be only one callback function.
• A callback function does not have a name and cannot be called.

Example

• This example shows how periodically receive wireless data and to save it in a variable.