A soft core processor refers to a microprocessor core that can be wholly implemented using logic synthesis. It can be implemented on any FPGA. Each time the processor’s design is used, it can be synthesized, or physically implemented, with the designer’s logic or FPGA tools.
A firm core processor is a semi-hardened core that may be provided in a format that is easier or faster to integrate into a larger design, but it still requires some synthesis steps to adapt it to a particular manufacturing process.
A hard core processor is a core that has been fully designed or hardened for optimal performance and lower power consumption, then provided as a physical design that can be manufactured as part of an ASIC or SoC.
