veriloggen 0.5.1

A library for constructing a Verilog HDL source code in Python

Veriloggen

A library for constructing a Verilog HDL source code in Python

Copyright (C) 2015, Shinya Takamaeda-Yamazaki

E-mail: shinya_at_is.naist.jp

License

Apache License 2.0 (http://www.apache.org/licenses/LICENSE-2.0)

What’s Veriloggen?

Veriloggen is an open-sourced library for constructing a Verilog HDL source code in Python.

Veriloggen is not a behavior synthesis (or high level synthesis). Veriloggen provides a lightweight abstraction of Verilog HDL AST. You can build up a hardware design written in Verilog HDL very easily by using the AST abstraction and the entire functionality of Python.

Veriloggen is not designed for designing a hardware by programmer directly, but is for providing an efficient abstraction to develop a more efficient domain specific language and tools.

Installation

Requirements

• Python: 2.7, 3.4 or later

Python3 is recommended.

• Icarus Verilog: 0.9.7 or later

Install on your platform. For exmple, on Ubuntu:

sudo apt-get install iverilog

• Jinja2: 2.8 or later

Install on your python environment by using pip:

pip install jinja2

• Pyverilog: 1.0.2 or later

Install from pip (or download and install from GitHub):

pip install pyverilog

Options

• pytest: 2.8.2 or later

• pytest-pythonpath: 0.7 or later

These softwares are required for running the tests in tests and examples:

pip install pytest pytest-pythonpath

• Graphviz: 2.38.0 or later

• Pygraphviz: 1.3.1 or later

These softwares are required for graph visualization by lib.dataflow:

sudo apt-get install graphviz
pip install pygraphviz

Install

Install Veriloggen:

python setup.py install

On Docker

Dockerfile is available, so that you can try Veriloggen on Docker without any installation on your host platform.

cd docker
sudo docker build -t user/veriloggen .
sudo docker run --name veriloggen -i -t user/veriloggen /bin/bash
cd veriloggen/examples/led/
make

Getting Started

You can find some examples in ‘veriloggen/examples/’ and ‘veriloggen/tests’.

Let’s begin veriloggen by an example. Create a example Python script in Python as below. A blinking LED hardware is modeled in Python. Open ‘hello_led.py’ in the root directory.

from __future__ import absolute_import
from __future__ import print_function
import sys
import os
from veriloggen import *

def mkLed():
    m = Module('blinkled')
    width = m.Parameter('WIDTH', 8)
    clk = m.Input('CLK')
    rst = m.Input('RST')
    led = m.OutputReg('LED', width)
    count = m.Reg('count', 32)

    m.Always(Posedge(clk))(
        If(rst)(
            count(0)
        ).Else(
            If(count == 1023)(
                count(0)
            ).Else(
                count(count + 1)
            )
        ))

    m.Always(Posedge(clk))(
        If(rst)(
            led(0)
        ).Else(
            If(count == 1024 - 1)(
                led(led + 1)
            )
        ))

    m.Always(Posedge(clk))(
        If(rst)(
        ).Else(
            Systask('display', "LED:%d count:%d", led, count)
        ))

    return m

def mkTest():
    m = Module('test')

    # target instance
    led = mkLed()

    # copy paras and ports
    params = m.copy_params(led)
    ports = m.copy_sim_ports(led)

    clk = ports['CLK']
    rst = ports['RST']

    uut = m.Instance(led, 'uut',
                     params=m.connect_params(led),
                     ports=m.connect_ports(led))

    lib.simulation.setup_waveform(m, uut, m.get_vars())
    lib.simulation.setup_clock(m, clk, hperiod=5)
    init = lib.simulation.setup_reset(m, rst, m.make_reset(), period=100)

    init.add(
        Delay(1000 * 100),
        Systask('finish'),
    )

    return m

if __name__ == '__main__':
    test = mkTest()
    verilog = test.to_verilog(filename='tmp.v')
    #verilog = test.to_verilog()
    print(verilog)

    sim = lib.simulation.Simulator(test)
    rslt = sim.run()
    print(rslt)

    #sim.view_waveform()

Run the script.

python hello_led.py

You will have a complete Verilog HDL source code named ‘tmp.v’ as below, which is generated by the source code generator.

module test #
(
  parameter WIDTH = 8
)
(

);

  reg CLK;
  reg RST;
  wire [WIDTH - 1:0] LED;

  blinkled
  #(
    .WIDTH(WIDTH)
  )
  uut
  (
    .CLK(CLK),
    .RST(RST),
    .LED(LED)
  );


  initial begin
    $dumpfile("uut.vcd");
    $dumpvars(0, uut, CLK, RST, LED);
  end


  initial begin
    CLK = 0;
    forever begin
      #5 CLK = !CLK;
    end
  end


  initial begin
    RST = 0;
    #100;
    RST = 1;
    #100;
    RST = 0;
    #100000;
    $finish;
  end


endmodule



module blinkled #
(
  parameter WIDTH = 8
)
(
  input CLK,
  input RST,
  output reg [WIDTH - 1:0] LED
);

  reg [32 - 1:0] count;

  always @(posedge CLK) begin
    if(RST) begin
      count <= 0;
    end else begin
      if(count == 1023) begin
        count <= 0;
      end else begin
        count <= count + 1;
      end
    end
  end


  always @(posedge CLK) begin
    if(RST) begin
      LED <= 0;
    end else begin
      if(count == 1023) begin
        LED <= LED + 1;
      end
    end
  end


  always @(posedge CLK) begin
    if(RST) begin
    end else begin
      $display("LED:%d count:%d", LED, count);
    end
  end


endmodule

You will also see the simulation result of the generated Verilog code on Icarus Verilog.

VCD info: dumpfile uut.vcd opened for output.
LED:  x count:         x
LED:  x count:         x
LED:  x count:         x
LED:  x count:         x
LED:  x count:         x
LED:  x count:         x
LED:  x count:         x
LED:  x count:         x
LED:  x count:         x
LED:  x count:         x
LED:  0 count:         0
LED:  0 count:         1
LED:  0 count:         2
LED:  0 count:         3
LED:  0 count:         4
...
LED:  9 count:       777
LED:  9 count:       778
LED:  9 count:       779
LED:  9 count:       780
LED:  9 count:       781
LED:  9 count:       782
LED:  9 count:       783

If you installed GTKwave and enable ‘sim.view_waveform()’ in ‘hello_led.py’, you can see the waveform the simulation result.

waveform.png

Publication

Not yet.

Related Project

Pyverilog - Python-based Hardware Design Processing Toolkit for Verilog HDL