The advantages of microcontroller are that all MCUs have on-chip resources to achieve a higher level of integration and reliability at a lower cost. An on-chip resource is a block of circuitry built into the MCU which performs some useful function under control of the MCU. Built-in resources increase reliability because they do not require any external circuitry to be working for the resource to function. They are pre-tested by the manufacturer and conserve board space by integrating the circuitry into the MCU.
Some of the more popular on-chip resources are memory devices, timers, system clock/oscillator, and I/O. Memory devices include read/write memory (RAM), read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), and electrically erasable memory (EEM). The term EEM actually refers to an engineering development version of an MCU where EEPROM is substituted for the ROM to reduce development time.
Timers include both real-time clocks and periodic interrupt timers. Other timer functions include timer compare and/or input capture lines.
I/O includes serial communication ports, parallel ports (I/O lines), analog-todigital (A/D) converters, digital-to-analog (D/A) converters, liquid crystal display drivers (LCD), and vacuum fluorescent display drivers (VFD).
Other built-in resources may include computer operating properly (COP) watchdog system which can be hardware or software based.
