Call Xilinx ISE from Python

Running Xilinx ISE implementation from a shell, with a script that has all the necessary parameters has the charm, that only the necessary settings are stored in a text file. On the Dillon Engineering web site a script named gen_ise_sh.py can be found, that creates a Makefile to run synthesis and the implementation tools, like place and route, from the command line.

Another way, implemented in later ISE versions, is to have a TCL script, that performs all the necessary settings and runs the implementation. For possible commands used in the TCL script, see the TCL Quickreference from Xilinx. Volker Stumpen has a nice tutorial about creating TCL scripts for ISE on the web page of IBM's Austin Research Laboratory.

As this page is about MyHDL and Python, a nice thing to have would be a Python wrapper for this functionality, that allows to run the implementation tools from a Python script. _xilinx.py is a script that contains two classes trying to cover the tool run in an object oriented way. The two classes are:

• Xilinx
• Fpga

The class Xilinx will wrap the Xilinx tool calls. This is done by creating a TCL-script with the necessary settings and then run the script.

The class Fpga contains the function around the .ucf-file. It is possible to specify which signal is connected to what FPGA pin and what parameters the pin should get associated with.

Here is an example how to use it. The _xilinx.py file is put under a folder called tools, which is added to the PYTHONPATH. So it can be used with the import statement.

from tools import *
 
 
if __name__ == '__main__':
 
  path = 'syn/spartan2'
  # set up pin configuration for the FPGA
  fpga = Fpga()
  fpga.setPin('clk50', 'P80')
  fpga.setPin('led', 'P71')
  fpga.setPin('btn', 'P77')
  fpga.setDevice('spartan2', 'xc2s200', 'pq208', '-5')
  print fpga
 
 
  # set up path
  imp = Xilinx(path, 'led')
  imp.setFpga(fpga)
  imp.addHdl(('counter.v','led.v'))
  imp.createTcl()
  imp.run()

The script is in an early state of development. I decided to publish it anyway, in hope it is useful for someone.