Embedded processors and controllers are specialized microprocessors and microcontrollers that are used in embedded systems. These are small, self-contained computer systems that are built into a larger device or system for a specific purpose, such as controlling a car engine or running a washing machine. Embedded processors and controllers are typically designed to be small, low-power, and highly efficient, in order to meet the specific requirements of the embedded system in which they are used.
ATMEL and AVR are both brands of microcontroller units (MCUs), which are specialized embedded processors that are designed for use in embedded systems. ATMEL is a brand of microcontrollers that is owned by Microchip Technology. AVR is a brand of microcontrollers that was originally developed by Atmel, but is now owned by Microchip Technology following their acquisition of Atmel in 2016. Both ATMEL and AVR microcontrollers are widely used in a variety of embedded applications.