BIO is a RISC-V-based I/O coprocessor designed for the Baochip-1x open-source 22nm SoC, conceived as an alternative to the Raspberry Pi PIO. After cloning and studying the PIO, the author found it consumed excessive FPGA resources and had a poor critical path due to its CISC-like instruction complexity and barrel shifters. The
Table of contents
BackgroundLessons Learned from the PIOA Caveat to PIO UsersAn Alternative ApproachRISC with a TwistDesign of the BIOA Simple BIO Code ExampleDetails of the FIFO and GPIOsSnapping to Quantum: A SPI ExampleTrade-offs Everywhere: Area, Clock Rates and Code SpaceOn Memory Trade-OffsCoding for BIO in CReflectionResourcesSort: