Improved Development Cycle for 8-bit FPGA-Based Soft-Macros Targeting Complex Algorithms

Abstract

Developing complex algorithms on 8-bit processors without proper development tools is challenging. This paper integrates a series of novel techniques to improve the development cycle for 8-bit soft-macros such as Xilinx PicoBlaze. The improvements proposed in this paper reduce development time significantly by eliminating the required resynthesis of the whole design upon HDL source code changes. Additionally, a technique is proposed to increase the maximum supported data memory size for PicoBlaze which facilitates development of complex algorithms. Also, a general verification technique is proposed based on a series of testbenches that perform code verification using comparison method. The proposed testbench scenario integrates “Inter-Processor Communication (IPC), shared memory, and interrupt” concepts that lays out a guideline for FPGA developers to verify their own designs using the proposed method. The proposed development cycle relies on a chip that has Programmable Logic (PL) fabric (to hold the soft processor) alongside of a hardened processor (to be used as algorithm verifier), therefore, a Xilinx Zynq Ultrascale+ MPSoC is chosen which has a hardened ARM processor. The development cycle proposed in this paper targets the PicoBlaze, but it can be easily ported to other FPGA macros such as Lattice Mico8, or any non-Xilinx FPGA macros.