Verilog Project for Tang Nano 9K Board

The repository contains a Verilog project specially designed for the Tang Nano 9K FPGA board. Its main objective is to provide automation for synthesizing, placing, and routing Verilog designs. This is achieved using a series of scripts that also facilitate the setup of the development environment and facilitate the FPGA programming process. The two primary scripts are build.sh, which oversees the entire synthesis to bitstream generation, and setenv.sh which handles the FPGA toolchain environment setup. An additional feature is the Docker integration, allowing the encapsulation of the development environment for easy replication and distribution.

Requirements

• yosys - https://github.com/YosysHQ/yosys
• nextpnr-gowin - https://github.com/YosysHQ/nextpnr
• openFPGAloader - https://github.com/trabucayre/openFPGALoader
• Docker with root permissions - https://docs.docker.com/engine/install/linux-postinstall/

Repository Structure

.
├── board
│   └── tangnano9k.cst  # Constraints file for Tang Nano 9K
├── build.sh            # Script for synthesis, placement, routing, and more
├── Docker
│   └── Dockerfile      # Dockerfile to set up the development environment
├── setenv.sh           # Script to set up the FPGA toolchain environment
└── src                 # Source folder the script looks for verilog files here 
    └── add.v           # Sample Verilog source file

Scripts Explained

build.sh

The build.sh script automates the following tasks:

1. Checks if yosys and nextpnr-gowin are available in PATH.
2. Defines constants used for synthesis and routing.
3. Contains an option to build and run a Docker environment (buildenv argument).
4. Houses logic to create necessary directories and clean them if needed (clean argument).
5. Includes logic to flash the bitstream to the FPGA board (flash argument).
6. Finds and synthesizes all Verilog files in the src/ directory using yosys.
7. Executes placement and routing using nextpnr-gowin.
8. Packs the result into a bitstream suitable for the target FPGA.

setenv.sh

The setenv.sh script sets up the FPGA toolchain environment:

1. Clones repositories for yosys, nextpnr, and openFPGALoader.
2. Compiles and installs each tool.
3. Cleans up by removing the cloned repositories.

Usage

Environment Setup

Run the build.sh script to set up the docker development environment.

./build.sh buildenv

This script will install the yosys, nextpnr-gowin and openFPGAloader inside the docker.

Synthesizing, Placing, Routing and Flashing

Run the build.sh script without any arguments to trigger the entire flow from synthesis to bitstream generation:

./build.sh build

To remove all generated files and directories, use:

./build.sh clean

After generating the bitstream, flash it to the FPGA board with:

./build.sh flash