RapidWright

Table of Contents

Background

RapidWright is a (mostly) open-source Java tool that provides you with a programming interface to Vivado designs. RapidWright contains its own Java classes to represent Xilinx FPGA devices, netlists, and how a netlist is implemented on the FPGA device. RapidWright interacts with Vivado through Xilinx .dcp (Design Checkpoint) and .edf (Electronic Design Interchange Format) files. You can create designs in Vivado, export them to a checkpoint and import them into RapidWright for analysis or modifications. The reverse process is also possible.

Although RapidWright is written in Java (available at Xilinx/RapidWright), it is possible to access the Java classes and methods directly from Python using the JPype tool. Setting up this environment takes only a few minutes, and instructions are provided here.

Starter Code

Here’s a basic Python script that opens a design and prints the number of cells and nets:

import jpype
import jpype.imports
from jpype.types import *

jpype.startJVM(classpath=["rapidwright-2021.2.1-standalone-lin64.jar"])

from com.xilinx.rapidwright.design import Design

def main():
    d = Design.readCheckpoint("design.dcp", "design.edf")

    print("Number of Cells:", len(d.getCells()))
    print("Number of Nets:", len(d.getNets()))


if __name__ == "__main__":
    main()

For this code to work, you will need to download rapidwright-2021.2.1-standalone-lin64.jar from the RapidWright Releases Page. You will also need to provide a design.dcp and design.edf file. These can be obtained from Vivado by running the following commands:

write_checkpoint <filename>.dcp
write_edif <filename>.edf

You should place all these files (including the rapidwright-2021.2.1-standalone-lin64.jar file) into your project directory along with your python script. The output of the script should look something like this:

==============================================================================
==                         Reading DCP: design.dcp                          ==
==============================================================================
Loading device from file xc7a200tsbg484-1
 XML Parse & Device Load:     0.475s
              EDIF Parse:     0.448s
        Read XDEF Header:     0.014s
        Read XDEF Caches:     0.023s
     Read XDEF Placement:     0.295s
INFO: Building uncommon Wire->Node cache...
      This might take a few seconds for large devices on the first call.  
      It is generally triggered when getting the Node from an uncommon Wire object.  
      To avoid printing this message, set Device.QUIET_MESSAGE=true or set the ENVIRONMENT variable RW_QUIET_MESSAGE=1.
INFO: Finished building uncommon Wire->Node cache
       Read XDEF Routing:     1.325s
------------------------------------------------------------------------------
         [No GC] *Total*:     2.581s
Number of Cells: 10185
Number of Nets: 11829

Documentation

The documentation for the various RapidWright classes can be found at https://www.rapidwright.io/javadoc/.

Here are a few useful classes: