axion-hdl 1.4.0

Automated AXI4-Lite Register Interface Generator for VHDL modules

Axion-HDL

AXI4-Lite register interfaces from VHDL, SystemVerilog, YAML, TOML, XML, or JSON. One command.

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Install

For users:

pip install axion-hdl

For development:

git clone https://github.com/bugratufan/axion-hdl.git
cd axion-hdl
python3 -m venv venv
source venv/bin/activate
pip install -e ".[dev]"  # Includes pytest, cocotb, etc.

Use

# From VHDL with @axion annotations
axion-hdl -s my_module.vhd -o output/

# From SystemVerilog with @axion annotations
axion-hdl -s my_module.sv -o output/

# From YAML/TOML/XML/JSON
axion-hdl -s registers.yaml -o output/
axion-hdl -s registers.toml -o output/

Output: VHDL/SystemVerilog modules, C headers, documentation, YAML/TOML/XML/JSON exports.

Define Registers

VHDL — embed in your code:

-- @axion_def BASE_ADDR=0x1000 CDC_EN
signal status  : std_logic_vector(31 downto 0); -- @axion RO
signal control : std_logic_vector(31 downto 0); -- @axion RW W_STROBE

SystemVerilog — same annotations, different syntax:

// @axion_def BASE_ADDR=0x1000 CDC_EN
logic [31:0] status;  // @axion RO
logic [31:0] control; // @axion RW W_STROBE

YAML — standalone file:

module: my_module
base_addr: "0x1000"
config:
  cdc_en: true
registers:
  - name: status
    access: RO
  - name: control
    access: RW
    w_strobe: true

TOML — clean, readable syntax:

module = "spi_master"
base_addr = "0x0000"

[config]
cdc_en = true
cdc_stage = 2

[[registers]]
name = "control"
addr = "0x00"
access = "RW"
w_strobe = true
description = "SPI control register"

[[registers]]
name = "status"
addr = "0x04"
access = "RO"
r_strobe = true
description = "SPI status register"

Output — one command:

axion-hdl -s spi_master.toml -o output --all

Generates: VHDL + SystemVerilog modules, C header, HTML docs, YAML/TOML/XML/JSON exports

Features

• Multi-format input — VHDL/SystemVerilog annotations, YAML, TOML, XML, JSON
• Multi-HDL output — Generate both VHDL and SystemVerilog register interfaces
• CDC support — built-in clock domain crossing synchronizers
• Subregisters — pack multiple fields into one address
• Wide signals — auto-split 64-bit+ signals across addresses
• Tested — 307+ tests, GHDL simulation verified

Documentation

📖 axion-hdl.readthedocs.io

Development & Testing

Quick start:

git clone https://github.com/bugratufan/axion-hdl.git
cd axion-hdl
make test  # Auto-installs dependencies and runs all tests

The make test command automatically:

• Creates a virtual environment if needed
• Installs all test dependencies
• Runs 307+ tests (Python + VHDL + cocotb)

Note: For SystemVerilog linting tests, verilator must be installed on your system (sudo apt install verilator) for make test to pass.

Manual setup (optional):

make setup-dev  # Create venv + install dependencies
source venv/bin/activate

CI/Automated environments:

AXION_AUTO_INSTALL=1 make test  # Skip prompt, auto-install

Contributing:

git checkout develop
git checkout -b feature/your-feature
# Make changes
make test  # Dependencies auto-installed on first run
# Submit PR to develop branch

License

MIT — Bugra Tufan