For more than three decades, system-level designers have employed FPGAs for multitude of reasons, but the two main factors are performance and flexibility. Many tasks executed in software running on a microprocessor or microcontroller will benefit from significant performance improvements when these tasks are instead implemented in hardware. That path usually leads to either an ASIC/SoC design or an FPGA.
When designing with ASICs and SoCs, however, there’s a caveat. If you’re absolutely certain that there will never be any changes in the associated algorithms, then freezing them into ASIC gates makes sense. These days, not much seems that stable. Standards change. Market needs change. If you freeze the wrong algorithm in ASIC gates, you will need to re-spin the chip.
Consequently, system-level designers often rely on FPGAs to execute algorithms at hardware processing speeds, but with the added flexibility to change the algorithm in milliseconds (or less) if required. Pairing an application processor or microcontroller with an FPGA on a circuit board is now common design practice. The processor runs most of the embedded system’s code and the FPGA accelerates tasks that need more performance than the processor can deliver.