Distribution channel customers designing high-performance, cost- and power-sensitive applications, such as vending machines, building management and heating-ventilation-air conditioning systems, exercise equipment and lighting control need highly integrated microcontrollers -- off the shelf -- that reduce system component count and fit their product requirements. There are also many wireless networking and infrastructure applications, internet appliances as well as special portable products, that need off-the shelf general purpose microcontrollers. Many of these users require microcontrollers running at speeds greater than 33 MHz with on-chip RAM and FLASH memory as well as an array of sophisticated peripherals that are easy to program in a high-level language. This article discusses the key elements of a general purpose microcontroller and its use in a real-time application. The interaction of the peripherals with the processor is essential for collecting, processing and outputting data. To better appreciate how these peripherals interact with the processor, a review of each of the major functions of a microcontroller will be discussed. The low power Motorola MMC2107 32-bit microcontroller architecture will be used as an example in designing a complex system using a minimum number of components.
