ABSTRACT
A soft-core processor is a microprocessor core that can be implemented entirely by using digital logic synthesis. It is typically instantiated on programmable hardware such as a field programmable gate array (FPGA). Many traditional devices that are interfaced to discrete microprocessors can also be connected to soft-core processors. The interface logic that is typically produced in the form of discrete components can be realized as logic instantiated in the FPGA along with the soft-core processor. The interface logic typically supplied by vendors of commercial soft-core processors includes gpio, Universal Asynchronous Receiver/Transmitter, Inter-Integrated Circuit, Serial Peripheral Interface, and others. There are many soft microprocessor cores available, both closed and open source. Xilinx and Altera are the two major vendors; other vendors include Lattice, Actel, and Quicklogic. The leading 32 bit soft-core processors include Altera Nios II and Xilinx Microblaze.
