Cocotb Waves

Table of Contents

• Introduction
• Installation
• Usage
• Classes & Methods

Introduction

This repository contains wavedrom svg generator for cocotb sims.

Installation

Installation from pip (release version, stable):

$ pip install cocotbext-waves

Usage

Example sampling AHB signals using cocotbext-ahb.

from cocotbext.waves import waveform

...

waves = waveform(
    clk=dut.hclk, name="ahb_test", hscale=3, debug=True
)
waves.add_signal(
    [
        dut.hsel,
        dut.haddr,
        dut.hburst,
        dut.hsize,
        dut.htrans,
        dut.hwdata,
        dut.hwrite,
        dut.hready_in,
    ],
    group="MOSI",
)
waves.add_signal(
    [
        dut.hrdata,
        dut.hready,
        dut.hresp,
    ],
    group="MISO",
)
waves.start()
...
<Running sim, issuing txns>
...
waves.save_svg()
waves.save_txt()

Output:

Classes & Methods

Class waveform

class waveform:
    def __init__(
        self,
        clk,
        name,
        hscale: int = 2,
        is_posedge: bool = True,
        debug: bool = False,
        start: bool = True
    ) -> None:

• clk: Synchronous clock used as the sample the signals
• name: Defines the object / filename, also part of the diagram header
• hscale: Horizontal scale for the SVG
• is_posedge: Defines clock model
• debug: Enable some debug messages
• start: Starts the signal monitoring

.start()/.stop()

Optional start/stop the sampling to create the diagram.y

.add_trigger(handle, val)

Adds a trigger to start sampling the signal, starts when handle.value == val.

.add_signal(color, is_clock, is_posedge_clock, clock_period, group)

Adds a signal to be monitored in the diagram. If it is a clock, other arguments can be populated, please note that signals from the same group have to be declared in a single method call.

.set_head/foot(text, tick, every)

Set header/foot propertries of the diagram, more info on wavedrom website.

.save_svg()

Stops the sampling and convert into SVG the final diagram.

.save_txt()

Stops the sampling and convert into .txt fmt the json.