The Arduino line of microcontrollers is very popular thanks to the programming library known as the Wiring API. This API provides simple functions that can be used by the programmer. These functions are implemented for all the Arduino microcontrollers. Therefore, the user can use the same (portable) code for any Arduino device chosen. The Wiring API has been implemented for MSP430 microcontrollers in the Energia IDE

To give you an idea of how an API is implemented, let’s write a function that’s similar in style to the Wiring API. The function finds the first available channel of Timer_A. A channel is considered available if its CCIE bit is disabled. This is the header of the function. It returns the first available channel out of Channels 0, 1, 2, in this order. If all the channels are used, the function returns -1. Write the code.

int get_available_timer_channel();