Trends in embedded-microprocessor design

When discussing microprocessors, we tend to think of the Intel x86 architecture and its competitors. Doing so, however, ignores the growing market for embedded microprocessors and controllers, in particular the growing 32-bit embedded-processor market. This movement toward longer instruction length may seem strange to developers of brake control systems or washing machines-and, indeed, forecasters predict that eight times more 8-bit than 32-bit embedded processors will ship in 1999. But as demand for more complex handheld and portable applications rises, this trend becomes more understandable. Today's 32-bit embedded-processor market includes more than 100 vendors and two dozen instruction set architectures. This article describes what these embedded CPUs are and how the requirements of embedded systems make them different from general-purpose CPUs.