This is a python module and command line fully compatible with WaveDrom, which is originally implemented in JavaScript. It is useful if you want to generate wavedrom diagrams from a python environment or simply don't want to install the Node.js environment just to use WaveDrom as simple command line.

WaveDromPy is for example used in sphinxcontrib-wavedrom to render wavedrom for Sphinx documentation. While the original project renders the diagrams in JavaScript in the browser, WaveDromPy renders them to SVG files.

This tool is a direct translation of original Javascript file WaveDrom.js to Python. No extra feature added. We seek to have it fully compatible.

The tool WaveDromPy directly converts WaveDrom compatible JSON files into SVG format.

It is most easy to just install wavedrom via pip/pypi:

pip install wavedrom

Alternatively you can install the latest version from this repository:

pip install git+https://github.com/wallento/wavedrompy

or from your local copy:

pip install .

You can either use the tool from Python:

import wavedrom
svg = wavedrom.render("""
{ "signal": [
 { "name": "CK",   "wave": "P.......",                                              "period": 2  },
 { "name": "CMD",  "wave": "x.3x=x4x=x=x=x=x", "data": "RAS NOP CAS NOP NOP NOP NOP", "phase": 0.5 },
 { "name": "ADDR", "wave": "x.=x..=x........", "data": "ROW COL",                     "phase": 0.5 },
 { "name": "DQS",  "wave": "z.......0.1010z." },
 { "name": "DQ",   "wave": "z.........5555z.", "data": "D0 D1 D2 D3" }
]}""")
svg.saveas("demo1.svg")

This will render a waveform as:

You can find more examples in the WaveDrom tutorial.

A second feature is that WaveDrom can render logic circuit diagrams:

import wavedrom
svg = wavedrom.render("""
{ "assign":[
  ["out",
    ["|",
      ["&", ["~", "a"], "b"],
      ["&", ["~", "b"], "a"]
    ]
  ]
]}""")
svg.saveas("demo2.svg")

This will render a as:

You can find more examples in the WaveDrom tutorial2.

Finally, wavedrom can draw registers as bitfields:

import wavedrom
svg = wavedrom.render("""
{"reg": [
  { "name": "IPO",   "bits": 8, "attr": "RO" },
  {                  "bits": 7 },
  { "name": "<o>B</o><b>R<i>K</i></b>",   "bits": 5, "attr": "RW", "type": 4 },
  { "name": "CPK",   "bits": 1 },
  { "name": "Clear", "bits": 3 },
  { "bits": 8 }
  ]
]}""")
svg.saveas("demo3.svg")

This will render as:

This mode is documented as part of the bit-field JavaScript package.

Alternatively, WaveDromPy can be called from the command line:

wavedrompy --input input.json --svg output.svg

The command line uses Python's JSON interpreter that is more restrictive (coherent with the JSOC spec), while the JavaScript json is more relaxed:

• All strings have to be written between quotes (""),
• Extra comma (,) not supported at end of lists or dictionaries

An AsciiDoctor example is provided to directly generate timing diagrams from AsciiDoctor formatted documents.