String | Multiple:
board_build.mcu is a microcontroller(MCU) type that is used by compiler to
recognize MCU architecture. The correct type of
board_build.mcu depends on
platform library. For example, the list of
board_build.mcu for “megaAVR Devices”
is described here.
The full list of
board_build.mcu for the popular embedded platforms you can find
in Boards section of Development Platforms. See “Microcontroller” column.