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Feature #1227

Updated by tin over 4 years ago

Сегодня интерфейс GPIB медленно заменяется более современными USB, LAN и другими менее популярными протоколами. Однако существует по прежнему огромное множество лабораторных приборов и измерительной аппаратуры оснащенной стандартным портом GPIB. Большинтсов промышленных и фабричных систем автоматизированно и управляется именно с помощью GPIB уже десятилетия. А это означает что по-прежнему требуется наличие GPIB-контроллера для выполнения кода програм и управлением шиной. 

 Обычно в этих целях используется обычный ПК в настольном либо промышленном исполнении, под управлением Windows или Linux систем, и совсем редко MAC OS. Большинство производителей поддерживают интерфейс GPIB с помощью библиотек и программ для своих продуктов.  

 Использование GPIB совместно с стандартным адаптером GPIB-USB обычно не вызывает каких-либо проблем или затруднений в Windows-среде, однако в мире Linux все часто заканчивается многими часами, если ваш дистрибутив не поддерживается официально, либо же опыта в использовании библиотек GPIВ нет. Попробуем разобраться в работе GPIB под Linux на примере популярного микрокомпьютера Raspberry Pi 

 h2. Адаптер интерфейса National Instruments GPIB-USB-HS 

 First, let's take a look on hardware interface which we will be using in this tutorial. 
 There are multiple versions of USB-GPIB interfaces from National Instruments, we use previous generation "GPIB-USB-HS":http://sine.ni.com/nips/cds/view/p/lang/en/nid/201586. There is already newer version "available, GPIB-USB-HS+":http://sine.ni.com/nips/cds/view/p/lang/en/nid/212429 for about same price ~600 USD new. 

 Features: 

 * Custom ASIC provides maximum IEEE 488.2 performance 
 * High-performance GPIB controller 
 * No GPIB cable requirement for instrument connection 
 * Transfer rates up to 1.8 MB/s (IEEE 488.1) and up to 7.9 MB/s (HS488) 
 * License included for NI-488.2 

 While NI site lists Linux support, it's declared only for RedHat, Scientific Linux and SUSE. If we want use it with something like "Raspberry Pi":https://www.raspberrypi.org with it's Debian-based Linux system we are alone in the wild. 

 " !http://xdevs.com/doc/National/GPIB-USB-HS/img/overview_1.jpg!":http://xdevs.com/doc/National/GPIB-USB-HS/img/overview.jpg 

 Very brief "datasheet":http://xdevs.com/doc/National/GPIB-USB-HS/GPIB-USB-HS_DS.pdf just covers basic installation and specification. 

 " !http://xdevs.com/doc/National/GPIB-USB-HS/img/top_1.jpg!":http://xdevs.com/doc/National/GPIB-USB-HS/img/top.jpg " !http://xdevs.com/doc/National/GPIB-USB-HS/img/chips_1.jpg!":http://xdevs.com/doc/National/GPIB-USB-HS/img/chips.jpg 

 Main micro-controller to interface USB side is Cypress CY7C68013A, which is "EZ-USB® FX2LP™ USB Microcontroller High-Speed USB Peripheral Controller":http://www.cypress.com/documentation/datasheets/cy7c68013a-cy7c68014a-cy7c68015a-cy7c68016a-ez-usb-fx2lp-usb based on 8051.  

 GPIB side is served by own National Instruments ASIC, TNT5004-AB, which is GPIB Controller with PCI and Generic interfaces. It's documentation is subject of NDA, but there is public datasheet for GPIB talker/listener only version "TNT5002-AB":http://xdevs.com/doc/National/GPIB-USB-HS/TNT5002.pdf, which brings light to most ASIC's inner structure. "Cypress CY7C1399BN":http://www.cypress.com/part/cy7c1399bnl-12zxct is just 256-Kbit (32K x 8) SRAM to store realtime data during transfers. System clock is generated by 40 MHz generator.  

 !http://xdevs.com/doc/National/GPIB-USB-HS/img/fx2lp.png! 

 There are also "Texas Instruments TLC7733I":http://www.ti.com/lit/ds/symlink/tlc7733.pdf and "Maxim MAX804CSA":http://www.maximintegrated.com/en/products/power/supervisors-voltage-monitors-sequencers/MAX804R.html supervisors, and few other small logic chips. No parts are populated on PCB's bottom side. 

 For comparison purposes, here's photo of older GPIB-USB-B adapter, which using Cypress FX and National Instruments TNT4882C-BT GPIB Controller chipset. Documentation for controller TNT4882*C* chip is also available only under NDA from NI, but talker/listener only version, TNT4882 without C have brief "datasheet here":http://xdevs.com/doc/National/GPIB-USB-B/TNT4882.pdf  

 !http://xdevs.com/doc/National/GPIB-USB-B/web.jpg! 

 Few extra photos of GPIB-USB-HS. Plastic cover is metallized on inner surfaces to aid EMI and shielding. 

 " !http://xdevs.com/doc/National/GPIB-USB-HS/img/back_1.jpg!":http://xdevs.com/doc/National/GPIB-USB-HS/img/back.jpg " !http://xdevs.com/doc/National/GPIB-USB-HS/img/side_1.jpg!":http://xdevs.com/doc/National/GPIB-USB-HS/img/side.jpg 

 Enough hardware, let's dig into Linux world to set everything up. 

 h2. Raspberry Pi setup 

 All information below is tested on Raspberry Pi 1 model B revision 2, using on-board USB connection. Linux version used was "RASPBIAN Debian Wheezy":https://www.raspberrypi.org/downloads/, which we already go through basic setup doing I2C stuff "before, in this article":/article/ddr4s/. If you need to setup system from scratch on blank SD card, suggest to reference "that article":/article/ddr4s/ first. 

 Below we go step by step for whole process of getting GPIB-USB-HS working with Raspberry Pi system. "Forum thread on EEVBlog.com" from member *bingo600* was a great help, and definitely saved loads of time and efforts. While he was using Beiming S82357 and Agilent 82357B, but idea behind flow is exactly same. 

 #1 Before we start installing stuff, highly recommended to update current packets. All commands below are issued under admin root rights, so if you don't usually logon under root, you may need use *sudo*. 

 pre. apt-get update 

 #2 Install Linux kernel image, as linux-gpib module versions are specific for each kernel branch, and they both need match.  

 pre. apt-get install linux-image-rpi-rpfv 

 In my case it put kernel verison 3.18.0. You can locate it in /boot directory, where two files should be present, such as *initrd.img-3.18.0-trunk-rpi* and *vmlinuz-3.18.0-trunk-rpi* 

 #3 In boot/config.txt append this at end of file , or it will boot the default "Foundation kernel" 

 pre. ************* SNIP *********************** 
 # Set params for "raspbian debian-style kernel" boot 
 kernel=vmlinuz-3.18.0-trunk-rpi 
 initramfs initrd.img-3.18.0-trunk-rpi followkernel 

 #4 Double check filenames and presence of files in /boot, otherwise your Raspberry Pi will *not boot*. If such happens, fix is easy. Just remove SD card, plug it into your PC and change config.txt file, as it's accessible from FAT filesystem under usual OS, unlike rest of linux partitions on Raspberry's SD card. 

 #5 After success with kernel change and boot, we can check kernel version and install header package: 

 pre. pi@tin ~ $ uname -a 
 Linux tin.pi 3.18.0-trunk-rpi #1 PREEMPT Debian 3.18.5-1~exp1+rpi16 (2015-03-28) armv6l GNU/Linux 
 pi@tin ~ $ sudo apt-get install linux-headers-rpi-rpfv 

 #6 Since we will be compiling lot of stuff later, worth to preinstall all packages and libraries, to make sure dependency are met correctly. 

 pre. apt-get install build-essential texinfo texi2html libcwidget-dev tcl8.4-dev tk8.4-dev libncurses5-dev libx11-dev binutils-dev bison flex libusb-1.0-0 libusb-dev libmpfr-dev libexpat1-dev tofrodos subversion autoconf automake libtool 

 #7. Now install linux-gpib itself. Enter home directory and run next: 

 pre. root@tin:/home/# mkdir linux-gpib   
 root@tin:/home/# cd linux-gpib 
 root@tin:/home/linux-gpib# svn checkout svn://svn.code.sf.net/p/linux-gpib/code/trunk linux-gpib-code 
 A      linux-gpib-code/linux-gpib 
 A      linux-gpib-code/linux-gpib/test 
 A      linux-gpib-code/linux-gpib/test/runtest 
 ... 
 ... 
 root@tin:/home/linux-gpib# cd linux-gpib-code/linux-gpib/ 

 #8 At this moment we have latest linux-gpib from SVN and ready to configure and install it. 

 pre. root@tin:/home/linux-gpib# cd linux-gpib-code/linux-gpib/ 
 root@tin:/home/linux-gpib/linux-gpib-code/linux-gpib# ./bootstrap 
 libtoolize: putting auxiliary files in `.'. 
 libtoolize: copying file `./ltmain.sh' 
 libtoolize: putting macros in AC_CONFIG_MACRO_DIR, `m4'. 
 libtoolize: copying file `m4/libtool.m4' 
 libtoolize: copying file `m4/ltoptions.m4' 
 libtoolize: copying file `m4/ltsugar.m4' 
 libtoolize: copying file `m4/ltversion.m4' 
 libtoolize: copying file `m4/lt~obsolete.m4' 
 configure.ac:102: installing `./compile' 
 configure.ac:39: installing `./config.guess' 
 configure.ac:39: installing `./config.sub' 
 configure.ac:20: installing `./install-sh' 
 configure.ac:20: installing `./missing' 
 examples/Makefile.am: installing `./depcomp' 
 ... 
 ... 

 #9 linux-gpib is using kernel headers, which version must match our kernel version. So make sure those installed as well: 

 pre. root@tin:/home/gpib/linux-gpib-3.2.21# apt-get install linux-headers-3.18.0 
 Reading package lists... Done 
 Building dependency tree 
 Reading state information... Done 
 ... 
 ... 
 The following NEW packages will be installed: 
   linux-headers-3.18.0-trunk-all linux-headers-3.18.0-trunk-all-armhf 
   linux-headers-3.18.0-trunk-rpi2 
 0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded. 
 Need to get 857 kB of archives. 
 After this operation, 6,807 kB of additional disk space will be used. 
 Do you want to continue [Y/n]? Y 
 ... 
 ... 
 Fetched 857 kB in 2s (365 kB/s) 
 Selecting previously unselected package linux-headers-3.18.0-trunk-rpi2. 
 (Reading database ... 97166 files and directories currently installed.) 
 Unpacking linux-headers-3.18.0-trunk-rpi2 (from .../linux-headers-3.18.0-trunk-rpi2_3.18.5-1~exp1+rpi16_armhf.deb) ... 
 Selecting previously unselected package linux-headers-3.18.0-trunk-all-armhf. 
 Unpacking linux-headers-3.18.0-trunk-all-armhf (from .../linux-headers-3.18.0-trunk-all-armhf_3.18.5-1~exp1+rpi16_armhf.deb) ... 
 Selecting previously unselected package linux-headers-3.18.0-trunk-all. 
 Unpacking linux-headers-3.18.0-trunk-all (from .../linux-headers-3.18.0-trunk-all_3.18.5-1~exp1+rpi16_armhf.deb) ... 
 Setting up linux-headers-3.18.0-trunk-rpi2 (3.18.5-1~exp1+rpi16) ... 
 Setting up linux-headers-3.18.0-trunk-all-armhf (3.18.5-1~exp1+rpi16) ... 
 Setting up linux-headers-3.18.0-trunk-all (3.18.5-1~exp1+rpi16) ... 

 #10 Now run *./configure* in linux-gpib directory to prepare it for our system environment. 

 pre. root@tin:/home/linux-gpib/linux-gpib-code/linux-gpib# ./configure 
 checking for a BSD-compatible install... /usr/bin/install -c 
 checking whether build environment is sane... yes 
 checking for a thread-safe mkdir -p... /bin/mkdir -p 
 checking for gawk... no 
 checking for mawk... mawk 
 checking whether make sets $(MAKE)... yes 
 checking whether to enable maintainer-specific portions of Makefiles... no 
 checking build system type... armv6l-unknown-linux-gnueabihf 
 checking host system type... armv6l-unknown-linux-gnueabihf 
 checking Linux kernel directory... ok 
 checking Linux kernel compile flags... Makefile:10: *** mixed implicit and normal rules: deprecated syntax ok 
 checking for gcc... gcc 

 #11 Compile and install linux-gpib 

 pre..  
 root@tin:/home/gpib/linux-gpib-3.2.21# make 
 make    all-recursive 
 make[1]: Entering directory '/home/gpib/linux-gpib-3.2.21' 
 Making all in include 
 make[2]: Entering directory '/home/gpib/linux-gpib-3.2.21/include' 
 make    all-am 
 make[3]: Entering directory '/home/gpib/linux-gpib-3.2.21/include' 
 make[3]: Nothing to be done for 'all-am'. 
 ... 
 ... 
 root@tin:/home/gpib/linux-gpib-3.2.21# make install 

 h2. Configuration for linux-gpib and interfacing 

 After everything successfully installed without errors, let's connect GPIB-USB-HS adapter to Raspberry Pi and try to talk with it. 

 p(#error_note). Make sure your Pi powered with good high-current USB cable and +5 VDC power supply with at least 1 Amp , as NI GPIB-USB-HS is taking some decent amount of power and with cheap USB cable connected to PC port it was causing unstable operation, LAN LEDs on Pi were blinking like crazy and nothing worked, as voltage drop too much.  

 Checking interface connection is simple, just run *lsusb* to see which devices are present on USB bus: 

 pre..  
 root@tin:/etc# lsusb 
 Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. 
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub 
 Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. 
 Bus 001 Device 004: ID 3923:709b National Instruments Corp. GPIB-USB-HS 

 p. Unlike old GPIB-USB-B, which need Cypress FX firmware upload after connection, GPIB-USB-HS does not need any firmware uploads and ready to work right from the box. 
 Let's load kernel module with *modprobe*: 

 pre..  
 root@tin:/home/gpib/linux-gpib-3.2.21# modprobe ni_usb_gpib 
 root@tin:/home/gpib/linux-gpib-3.2.21# 

 p. Should be no error messages here. Can check if module was correctly used as well by *lsmod*. 

 pre..  
 root@tin:/home/gpib/linux-gpib-3.2.21# lsmod 
 Module                    Size    Used by 
 i2c_dev                   6970    0 
 i2c_bcm2708               5306    0 
 ni_usb_gpib              26063    0 
 gpib_common              31031    1 ni_usb_gpib 

 p. Now I tried using gpib_config tool to test operation, but got nasty error instead: 

 pre..  
 root@tin:/home/gpib/linux-gpib-3.2.21# gpib_config 
 failed to configure boardtype: ni_usb_gpib 
 failed to configure board 
 main: Invalid argument 

 p. Oops... After some amount of trial and error, and googling similar issues on web, answer is simple: this is due to actual driver called different name compared to kernel module.  
 After modify /etc/gpib.conf like below: 

 pre..  
 board_type = "ni_usb_b">/* type of interface board being used */ 
     
 p. Everything working well now: 

 pre..  
 root@tin:/home/gpib/linux-gpib-3.2.21# gpib_config 
 root@tin:/home/gpib/linux-gpib-3.2.21#  

 p. No errors, yey! Let's test how it works now. 

 h2. Testing GPIB operation 

 To test I had NI GPIB-USB-HS connected to "Keithley 2002 bench digital multimeter":/review/kei2002/. Instrument is configured with GPIB Address = 17. 

 pre..  
 root@tin:/# ibtest 
 Do you wish to open a (d)evice or an interface (b)oard? 
         (you probably want to open a device): d 
 enter primary gpib address for device you wish to open [0-30]: 17 
 trying to open pad = 17 on /dev/gpib0 ... 
 You can: 
         w(a)it for an event 
         ... 
         ... 
         (r)ead string 
         perform (s)erial poll (device only) 
         change (t)imeout on io operations 
         request ser(v)ice (board only) 
         (w)rite data string 
 : w 
 enter a string to send to your device: *IDN? 
 sending string: *IDN? 

 gpib status is: 
 ibsta = 0x2100    < END CMPL > 
 iberr= 0 

 ibcnt = 6 
 You can: 
         w(a)it for an event 
         ... 
         ... 
         (r)ead string 
         perform (s)erial poll (device only) 
         change (t)imeout on io operations 
         request ser(v)ice (board only) 
         (w)rite data string 
 : r 
 enter maximum number of bytes to read [1024]: 1024 
 trying to read 1024 bytes from device... 
 received string: 'KEITHLEY INSTRUMENTS INC.,MODEL 2002,1167961,A09    /A02' 
 Number of bytes read: 57 
 gpib status is: 
 ibsta = 0x2100    < END CMPL > 
 iberr= 0 

 ibcnt = 57 

 p. Now we can confirm that interface is working, and data send/received correctly.  

 h2. Python-application to talk GPIB from Raspberry Pi 

 It's time to write some simple program to talk with our instruments over GPIB. 
 One of easy choices would be using Python, as this high-level language is very easy to write data-logging programs and format data, without worry much about low-level coding. 

 To use GPIB in Python we need to have python-dev library installed and working: 

 pre..  
 root@tin:/# apt-get install python-dev 
 Reading package lists... Done 
 Building dependency tree 
 Reading state information... Done 
 The following extra packages will be installed: 
   libssl-dev libssl-doc python2.7-dev 
 The following NEW packages will be installed: 
   libssl-dev libssl-doc python-dev python2.7-dev 
 0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded. 
 Need to get 2,699 kB/31.4 MB of archives. 
 After this operation, 41.4 MB of additional disk space will be used. 
 Do you want to continue [Y/n]? Y 
 .... 
 Setting up python2.7-dev (2.7.3-6+deb7u2) ... 
 Setting up python-dev (2.7.3-4+deb7u1) ... 

 p. Python-dev library is needed to access GPIB module. 
 Now we can install python egg to include *Gpib* module with our python system environment: 

 pre..  
 root@tin:/home/linux-gpib-code/linux-gpib/language/python# python ./setup.py    install 
 running install 
 running build 
 running build_py 
 creating build 
 creating build/lib.linux-armv6l-2.7 
 copying Gpib.py -> build/lib.linux-armv6l-2.7 
 running build_ext 
 building 'gpib' extension 
 creating build/temp.linux-armv6l-2.7 
 gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fPIC -I../../include -I/usr/include/python2.7 -c gpibinter.c -o build/temp.linux-armv6l-2.7/gpibinter.o 
 gcc -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-z,relro build/temp.linux-armv6l-2.7/gpibinter.o -L../../lib/.libs -lgpib -lpthread -o build/lib.linux-armv6l-2.7/gpib.so 
 running install_lib 
 copying build/lib.linux-armv6l-2.7/Gpib.py -> /usr/local/lib/python2.7/dist-packages 
 copying build/lib.linux-armv6l-2.7/gpib.so -> /usr/local/lib/python2.7/dist-packages 
 byte-compiling /usr/local/lib/python2.7/dist-packages/Gpib.py to Gpib.pyc 
 running install_egg_info 
 Writing /usr/local/lib/python2.7/dist-packages/gpib-1.0.egg-info 

 p. Simple Python test can help to check access, for multimeter sitting on GPIB bus with address 17. Test is simple sending IDN? request and reading back 100 bytes: 

 pre..  
 root@tin:/home/linux-gpib/linux-gpib-code/linux-gpib/language/python# python 
 Python 2.7.3 (default, Mar 18 2014, 05:13:23) 
 [GCC 4.6.3] on linux2 
 Type "help", "copyright", "credits" or "license" for more information. 
 >>> import Gpib 
 >>> inst = Gpib.Gpib(0,17) # Device address 17 
 >>> inst.write("*IDN?") 
 >>> inst.read(100) # read 100 bytes 
 'KEITHLEY INSTRUMENTS INC.,MODEL 2002,1167961,A09    /A02    \n' 
 >>>  

 p. Hope this article help to use little, but mighty Raspberry Pi with industry standard GPIB instrumentation. Size and capabilities of small microcomputer, such as Raspberry Pi can make something wild possible, such as integrating it into old GPIB-interfaced instruments to bring modern computing power and interfacing, such as interactive web via LAN port or even having instrument on remote location, controlled thru internet. No need big bulky computer with Windows tied to it. 

 pre..  
 # xDevs.com Python test GPIB app 
 # http://xdevs.com/guide/ni_gpib_rpi/ 
 import sys 
 import Gpib 
 inst = Gpib.Gpib(0,17) # Instrument GPIB Address = 17 
 inst.write(":DISP:WIND:TEXT:DATA 'Raspberry Pi GPIB;)'") 
 inst.write(":DISP:WIND2:TEXT:DATA 'xdevs.com/guide/ni_gpib_rpi'") 
 inst.write(":DISP:WIND:TEXT:STAT ON") 
 inst.write(":DISP:WIND2:TEXT:STAT ON") 

 p. " !http://xdevs.com/doc/Keithley/2002/photo/xDevs.com/kei2002_rpi_1.jpg!":http://xdevs.com/doc/Keithley/2002/photo/xDevs.com/kei2002_rpi.jpg !ahttp://xdevs.com/doc/Keithley/2002/photo/xDevs.com/kei2002_rpi_1.jpg!":http://xdevs.com/doc/Keithley/2002/photo/xDevs.com/kei2002_rpi.jpg 

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