Demand Driven Assembly of FPGA Configurations Using Partial Reconfiguration, Ubuntu Linux, and PYNQ

• Main Authors: Goeders, Jeffrey, Gaskin, Tanner, Hutchings, Brad
• Format: Conference Proceeding
• Language: English
• Subjects: Field programmable gate arrays; FPGA; Hardware; Kernel; Linux; Partial Reconfiguration; Pins; PYNQ
• ISSN: 2576-2621
• DOI: 10.1109/FCCM.2018.00032

The PYNQ system (Python Productivity for Zynq) is notable for combining a monolithic preconfigured bitstream, Ubuntu Linux, Python, and Jupyter notebooks to form an FPGA-based system that is far more accessible to non-FPGA experts than previous systems. In this work, the monolithic pre-configured PYNQ bitstream is replaced with a combination of a simple base bitstream containing several partial reconfiguration regions and a library of partial bitstreams that implement a variety of hardware interfaces such as: GPIO, UART, Timer, IIC, SPI, Real-Time Clock, etc., that interface to various Pmod-based peripherals. When peripherals are plugged into a Pmod socket at run-time, corresponding partial reconfigurations and standard device drivers can be automatically loaded into the Ubuntu kernel using device-tree overlays. This demand-driven, partially-reconfigured approach is found to be advantageous to the monolithic bitstream because: 1) it provides similar functionality to the monolithic bitstream while consuming less area, 2) it provides a way for users to modify or augment hardware functionality without requiring the user to develop a new monolithic bitstream, 3) run-time demand loading of partial bitstreams makes the system more responsive to changing conditions, and 4) implementation issues such as timing-closure, etc., are simplified because the base bitstream circuitry is smaller and less complex.