PyBfms Wishbone Library

The PyBFMs Wishbone library provides Bus Functional Models (BFMs) to allow Python testbench environments to use the Wishbone bus protocol.

Installation

The Wishbone BFMs library can be installed via PyPi.org or directly from GitHub.

Installing from PyPi:

% pip install pybfms_wishbone

Installing from GitHub:

% pip install https://github.com/pybfms/pybfms_wishbone

Provided BFMs

The Wishbone BFM library provides three BFMS:

• Inititor BFM – Initiates accesses on a Wishbone interface

• Target BFM – Receives and responds to accesses on Wishbone interface

• Monitor BFM – Passively monitors traffic on a Wishbone interface

Initiator BFM

Signal-level Interface

module wb_initiator_bfm #(
      parameter ADDR_WIDTH = 32,
      parameter DATA_WIDTH = 32
      ) (
      input                            clock,
      input                            reset,
      output reg[ADDR_WIDTH-1:0]       adr,
      output reg[DATA_WIDTH-1:0]       dat_w,
      input[DATA_WIDTH-1:0]            dat_r,
      output reg                       cyc,
      input                            err,
      output reg[(DATA_WIDTH/8)-1:0]   sel,
      output reg                       stb,
      input                            ack,
      output reg                       we
      );

Python API

Created on Nov 21, 2020

@author: mballance

class wishbone_bfms.wb_initiator_bfm.WbInitiatorBfm

async write(adr, dat, sel)

Write data according to the mask ‘sel’.

Note that this call will block until the first reset is received

async read(adr)

Read data from the system.

Note that this call will block until the first reset is received

async wait(cycles)

Wait for the specified number of interface-clock cycles.

Note that this call does not wait for a reset

Target BFM

Signal-level Interface

module wb_target_bfm #(
      parameter ADDR_WIDTH = 32,
      parameter DATA_WIDTH = 32
      ) (
      input                        clock,
      input                        reset,
      input[ADDR_WIDTH-1:0]        adr,
      input[DATA_WIDTH-1:0]        dat_w,
      output reg[DATA_WIDTH-1:0]   dat_r,
      input                        cyc,
      output reg                   err,
      input[(DATA_WIDTH/8)-1:0]    sel,
      input                        stb,
      output reg                   ack,
      input                        we
      );

Python API

Created on Nov 21, 2020

@author: mballance

class wishbone_bfms.wb_target_bfm.WbTargetBfm

set_responder(responder)

access_ack(*args)