/potato

A simple RISC-V processor for use in FPGA designs.

Primary LanguageVHDLBSD 3-Clause "New" or "Revised" LicenseBSD-3-Clause

The Potato Processor

Note that the master branch may be in an unstable state. Use one of the releases to avoid problems when compiling the code.

Processor architecture overview diagramme

The Potato Processor is a simple RISC-V processor for use in FPGAs. It implements the 32-bit integer subset of the RISC-V specification version 2.0 and supports the machine mode and the Mbare addressing environment of the RISC-V privileged architecture, version 1.7.

The processor has been tested on a Arty board using the example SoC design provided in the example/ directory and the Hello World application available in software/hello, as well as the SHA256 benchmark application available in software/sha256. Synthesis and implementation has been tested on various versions of Xilinx' Vivado, most recently version 2017.2.

Features

  • Supports the complete 32-bit RISC-V base integer ISA (RV32I) version 2.0.
  • Supports machine mode and the Mbare addressing environment defined in the RISC-V privileged architecture version 1.7.
  • Supports up to 8 individually maskable external interrupts (IRQs).
  • 5-stage "classic" RISC pipeline.
  • Supports the Wishbone bus, version B4.

Peripherals

The project includes a variety of Wishbone-compatible peripherals for use in system-on-chip designs based on the Potato processor. The main peripherals are:

  • Timer - a 32-bit timer with compare interrupt
  • GPIO - a configurable-width generic GPIO module
  • Memory - a block RAM memory module
  • UART - a UART module with hardware FIFOs and configurable baudrate

Quick Start/Instantiating

To instantiate the processor, add the source files from the src/ folder to your project. Use the pp_potato entity to instantiate a processor with a wishbone interface. Some generics are provided to configure the processor core.

An example System-on-Chip for the Arty development board can be found in the example/ directory of the source repository.

Compiler Toolchain

To program the processor, you need an appropriate compiler toolchain. Follow the instructions on the RISCV tools repository to build and install a toolchain.

Reporting bugs and issues

Bugs and issues related to the Potato processor can be reported on the project's GitHub page.