Library of drivers for AVR microcontrollers
The library strives to abstract away many of AVR's irregularities among the different MCUs. There is on one side drives for the on-chip capabilities, like GPIO, timers, A/D converters, UART, etc. On the other side the library provides some functionility that is typically in the Ada run time system or standard library, like real-time functions or string handling functions.
The main incentive to write special packages in the AVR hierarchy instead of the Ada hierarchy are the size constraints of the 8bit microcontrollers. Some of them only have a few bytes of RAM. You then think twice if you want your string variables indexed by a 8bit wide or 16bit wide index.
The library makes heavy use of the GNAT preprocessor. All compilations
have the symbol of the respective MCU name defined. The UART/Serial
interface distinguishes between UART, USART, USART0, and USART1 for
example. See the file mcu_capabilities.gpr.