intel_jtag_uart

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intel_jtag_uart is a Python module that can be used to interact with the JTAG UART instances inside Intel FPGA designs.

The official ways to do this are either interactively, through nios2-terminal utility, or by scripting some TCL code inside the Quartus System Console. There is no official straightforward way to interact with a JTAG UART with Python.

This module is a wrapper around the jtag_atlantic shared library/DLL that is part of any modern Quartus installation. (jtag_atlantic is the internal code name for the JTAG UART.)

To use this module, you need access to the jtag_atlantic shared library as well as the jtag_client shared library, which provides lower level JTAG-related functions.

Usage

• Install this package with pip3 install intel_jtag_uart.

• Point to the jtag_atlantic and jtag_client shared libraries, so that the module can find it.

  The module uses the following sequence to find these libraries:

  1. Look in the directory in which intel_jtag_uart.py is located
  2. Look in the directory in which the executable that uses this module is located
  3. Use the OS-provided way to find shared libraries. (E.g. for Linux, it will check the directories of the $LD_LIBRARY_PATH environment variable.)
  4. Look in the $QUARTUS_ROOTDIR directory

  Most default Quartus installations will have $QUARTUS_ROOTDIR environment variable set to the correct directory, so everything should just work™.

• Use some variation of the script below:

import intel_jtag_uart

try:
    ju = intel_jtag_uart.intel_jtag_uart()

except Exception as e:
    print(e)
    sys.exit(0)

ju.write(b'r')
time.sleep(1)
print("read: ", ju.read())

The script sends r to the JTAG UART, waits 1 seconds for a reply, and reads the reply, if there is any. If you have an Arrow/Terasic DECA FPGA board, you can check things out right away with a precompiled example bitstream.

Full List of Functions/Methods

Use the source, Luke!

This module is a very thin wrapper around a handful of function calls that are mostly self-explanatory.

Bug Reports/Comments/Questions

Bug reports, comments, or questions can be entered through the GitHub issue tracker of this project.

References

• The Intel JTAG UART - Add a Serial Console to Your Design without Extra IO Pins
• Write Your Own C and Python Clients for the Intel JTAG UART
• jtag_uart_example project
• intel-jtag-uart on pypi.org