Embedded Systems are basically electronic systems that embedded with a microcontroller or a processor or a DSP chip. They are specially designed to perform dedicated task based on the firmware (code) that loaded into their flash memory (ROM).
This firmware initialize the peripherals, integrate various sensors and actuators. Firmware contains logics, algorithms and protocols.
Partitioning of the design
Iteration and refinement of the partitioning
Independent design tasks
Integration of the hardware and software components