==================================================
 Updating the Prologix USB-GPIB firmware on Linux
==================================================


:author: David Douard
:Category: Electronics
:Tags: test equipment, GPIB, Prologix


Prologix_ sell several low cost GPIB controllers. I have one their old
deprecated dongle "GPIB-USB Controller 4.2" and had fun with it with
my pygpibtoolkit_ project.

It's a very simple dongle consisting in an Atmel ATMega164P
microcontroller and a FTDI FT245FL chip for the USB<->RS232
convertion.

.. image:: {filename}images/prologix/prologix_4.2_small.jpg
   :alt: The Prologix GPIB-USB controller.

Unfortunately, it's no longer available (I find this unfortunate
because it was really cheap, and very useful for hobbyist like me).


Upgrading the buggy firmware
============================
	 
My controller had the version 5.2 of the firmware, which really is
buggy. For example if a device on the GPIB bus is continuously sending
data and the controller is in "auto" mode (in which it automatically
perform a reading of the available data), then it was impossible to
send it commands anymore.

Unfortunately, the Prologix web site only describe the product as "No
longer in production". There is still an available FAQ_ and the `user
manual`_, but the firmware update procedure is not described any more.

However, the `directory serving all the firmwares`_ for their products
still have the firmwares for this device. The latest published version
is the `4.2-6.95`_ (in fact, it's the version 6.95 of the firware for
the version 4.2 of the USB-GPIB controller).

The content of this archive is::

  unzip -l ~/Downloads/gpib-usb-4.2-6.95.zip 
  Archive:  /home/david/Downloads/gpib-usb-4.2-6.95.zip
    Length      Date    Time    Name
  ---------  ---------- -----   ----
     244837  2007-07-08 23:57   avrdude.conf
     186880  2007-07-08 23:57   avrdude.exe
      31162  2010-09-21 10:57   m16.hex
      31542  2010-09-21 10:57   m164.hex
      61440  2010-06-16 18:21   PxUpdate.exe
        409  2009-01-21 11:00   readme.txt
  ---------                     -------
     556270                     6 files


Obviously, Windows stuff only, and no documentation on how to upgrade
the device on Linux.

But the fact it uses avrdude_ is good sign it might to find solutions
on Linux. According the names of the hex files, it seems there have 2
versions of the hardware, one with a ATMega16 and one with a
ATMega164P (mine uses a 164P).

Now, the question is: haw is the AVR programmed? There are dozens of
'backends' available on avrdude.

Doing a ``string`` on the main exe in thie archive, PxUpdate.exe,
shows a few interesting things, especially this::

  strings PxUpdate.exe | grep -i avr
  avrdude.exe -p %s -P \\.\COM%d -c avr109 -u -e -U flash:w:%s
  AVRBOOT

So we know the commande line used by this firmware update tool, and we
known it uses the AVR's bootloader as decribed in the AVR109_
application note.

But any attempt to read the content of the flash using::

  avrdude -p m164p -c avr109 -U flash:r:flash.hex:i

fails stating the avr does not respond::

  avrdude -P /dev/ttyUSB0  -p m164p -c avr109 -v -v -U flash:r:flash2.hex:i

  avrdude: Version 6.1, compiled on Sep 11 2014 at 20:00:34
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "/etc/avrdude.conf"
         User configuration file is "/home/david/.avrduderc"
         User configuration file does not exist or is not a regular file, skipping

         Using Port                    : /dev/ttyUSB0
         Using Programmer              : avr109
         AVR Part                      : ATmega164P
         Chip Erase delay              : 55000 us
         PAGEL                         : PD7
         BS2                           : PA0
         RESET disposition             : dedicated
         RETRY pulse                   : SCK
         serial program mode           : yes
         parallel program mode         : yes
         Timeout                       : 200
         StabDelay                     : 100
         CmdexeDelay                   : 25
         SyncLoops                     : 32
         ByteDelay                     : 0
         PollIndex                     : 3
         PollValue                     : 0x53
         Memory Detail                 :

                                  Block Poll               Page                       Polled
           Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW  MaxW   ReadBack
           ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
           eeprom         4    10   128    0 no        512    4      0  9000  9000 0xff 0xff
           flash         33     6   128    0 yes     16384  128    128  4500  4500 0xff 0xff
           lock           0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           lfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           hfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           signature      0     0     0    0 no          3    0      0     0     0 0x00 0x00
           calibration    0     0     0    0 no          4    0      0     0     0 0x00 0x00

         Programmer Type : butterfly
         Description     : Atmel AppNote AVR109 Boot Loader

  Connecting to programmer: .avrdude: ser_recv(): programmer is not responding
  avrdude: butterfly_recv(): programmer is not responding

	 
So there is something else required to put the device under firmware
upgrade state. I was wondering is there is an undocumented controller
commands (anything starting with ``++`` is interpreted as a controller
command, so I searched for the ``++`` string in ``PxUpdate.exe``::

  strings PxUpdate.exe | grep ++
  Microsoft Visual C++ Runtime Library
  ++rst

No magic undocumented command, but a reset of the controller is
performed by this tool. Let's try this::

  stty -F /dev/ttyUSB0 speed 115200 cs8  -cstopb -parenb 
  echo -en '++rst\r' > /dev/ttyUSB0; avrdude -P /dev/ttyUSB0  -p m164p -c avr109 -v -v -U flash:r:flash2.hex:i
  avrdude: Version 6.1, compiled on Sep 11 2014 at 20:00:34
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "/etc/avrdude.conf"
         User configuration file is "/home/david/.avrduderc"
         User configuration file does not exist or is not a regular file, skipping

         Using Port                    : /dev/ttyUSB0
         Using Programmer              : avr109
         AVR Part                      : ATmega164P
         Chip Erase delay              : 55000 us
         PAGEL                         : PD7
         BS2                           : PA0
         RESET disposition             : dedicated
         RETRY pulse                   : SCK
         serial program mode           : yes
   
         parallel program mode         : yes
         Timeout                       : 200
         StabDelay                     : 100
         CmdexeDelay                   : 25
         SyncLoops                     : 32
         ByteDelay                     : 0
         PollIndex                     : 3
         PollValue                     : 0x53
         Memory Detail                 :

                                  Block Poll               Page                       Polled
           Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW  MaxW   ReadBack
           ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
           eeprom         4    10   128    0 no        512    4      0  9000  9000 0xff 0xff
           flash         33     6   128    0 yes     16384  128    128  4500  4500 0xff 0xff
           lock           0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           lfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           hfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           signature      0     0     0    0 no          3    0      0     0     0 0x00 0x00
           calibration    0     0     0    0 no          4    0      0     0     0 0x00 0x00

         Programmer Type : butterfly
         Description     : Atmel AppNote AVR109 Boot Loader

  Connecting to programmer: .
  Found programmer: Id = "AVRBOOT"; type = S
    Software Version = 1.0; Hardware Version = 1.0
  Programmer supports auto addr increment.
  Programmer supports buffered memory access with buffersize=128 bytes.

  Programmer supports the following devices:
    Device code: 0x76

  avrdude: devcode selected: 0x76
  avrdude: AVR device initialized and ready to accept instructions

  Reading | ################################################## | 100% 0.00s

  avrdude: Device signature = 0x1e940a
  avrdude: safemode: Fuse reading not support by programmer.
              Safemode disabled.
  avrdude: reading flash memory:

  Reading | ################################################## | 100% 0.26s

  avrdude: writing output file "flash2.hex"

  avrdude done.  Thank you.

Much better!

Now I can upgrade the firmware::

  echo -en '++rst\r' > /dev/ttyUSB0; avrdude -P /dev/ttyUSB0  -p m164p -c avr109 -v -v -U flash:w:m164.hex
  
Et voilà! The Prologix GPIB-USB interface is upgraded to the latest
available software. From what I've seen so far, it seems more stable
(at least I can read data from my HP5442A and HP3456A in "fast" mode
without loosing my GPIB controller.)


.. _`4.2-6.95`: http://prologix.biz/downloads/gpib-usb-4.2-6.95.zip
.. _Prologix: http://prologix.biz/
.. _FAQ: http://prologix.biz/gpib-usb-4.2-faq.html
.. _`user manual`: http://prologix.biz/downloads/PrologixGpibUsbManual-4.2.pdf
.. _pygpibtoolkit: https://www.logilab.org/project/pygpibtoolkit
.. _`directory serving all the firmwares`: http://prologix.biz/downloads/
.. _avrdude: http://savannah.nongnu.org/projects/avrdude/
.. _avr109: http://www.atmel.com/Images/doc1644.pdf
