| A | B |
|---|
| HARDWARE | physical computing machinery like an MCU or laptop computer. |
| SOFTWARE | a set of instructions that a computer runs |
| CPU | central processing unit, containing the ALU and all support circuitry immediately connected to it. |
| ALU | arithmetic / logic unit, where computation is done |
| TIMER | used to time various functions |
| MEMORY | binary information storage, not part of the CPU. |
| RAM | random access memory, where data can be stored (write) and retrieved (read) as often as desired. |
| ROM | read-only memory, which holds the program and any unchanging data. |
| VOLATILE | memory that loses its data when power is turned off. RAM is volatile |
| NONVOLATILE | memory that keeps its data when power is turned off. ROM is nonvolatile |
| PROM | programmable ROM that allows the user to load the program |
| EPROM | ROM that can be erased by UV light and reloaded, usually used in program development. |
| EEPROM | EPROM that can be erased electrically |
| BUS | wires used to move data and instructions around. |
| PORT | an interface that allows the MCU to communicate with the outside world |
| SYSTEM CLOCK | a continuous squarewave signal that controls the timing of all functions |
| INTERRUPT | causes the MCU to stop its normal program execution and go to a special section of the program, usually a subroutine, to deal with the interrupt. This is called servicing the interrupt. |
