Introduction
When writing an Mbed OS program, you may need to:
- Set up a serial connection to your board so you can flash and debug your program.
 - Select or create a build profile to pass flags to the compiler when building your programs.
 - Use build rules to include or exclude files and directories from your build.
 - Use the configuration system to define how your board uses features and the bootloader.
 - Modify or set up a new target.