This paper gives the digit-serial DSP libraries used to implement the digit-serial DSP architecture for field programmable gate arrays (FPGAs) and compares schematic-based FPGA design with design based on logic synthesis for digit-serial DSP libraries. It describes the design of digit-serial addition/subtraction, multiplication and delay elements and indicates also how digit-serial FIR filter can be implemented. The FPGA device utilization and critical path delay of digit-serial DSP libraries are calculated and described.