Embedded systems have elements of hardware and software, and these are brought together into a working system. The systems engineering process, from requirements to testing and post-deployment support is discussed. There are known approaches that work. Software is a different animal than hardware, but the top-level principles for developing and testing derive from the same principles. Programmable hardware, in terms of FPGA's and SoC's introduce complexity, but can be addressed by the same engineering best practices.