Semiconductor, ROM-based microcomputers have one of two heritages - calculators or microprocessors. Similar paths were followed in the evolution of the automobile. The Model-T Ford and mid-range autos like the Buick, led to the consolidated automobile designs of the 1930’s. By 1930 the basic inventions were past, and numerous refinements were in the future.The evolution of ROM-based microcomputers have reached the same point in 1980. The coming era will take advantage of features that are available now. The Motorola M6805 Family is typical of a modern program architecture with flexible system configurations. Among the program benefits are multilevel subroutines, look-up tables, interrupts, timers, flexible addressing modes and multifunction instructions. The systems configurer gets a variety of ROM and RAM sizes, various I/O features, plus a choice of HMOS or CMOS technologies.