2c810c12e3
Add some info to the Install section about reserving devices for manual configuration using the comedi_num_legacy_minors module parameter.
334 lines
12 KiB
XML
334 lines
12 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
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"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
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<!ENTITY % comedilib_entities SYSTEM "comedilib.ent">
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%comedilib_entities;
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]>
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<section id="install">
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<title>
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Configuration
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</title>
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<para>
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This section assumes that you have successfully compiled and installed
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the &comedi; software, that your hardware device is in your computer,
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and that you know the relevant details about it, i.e., what kind of
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card it is, any jumper settings related to input ranges, the
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I/O base address and IRQ for old non-plug-n-play boards, etc.
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</para>
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<section id="cardconfiguration">
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<title>
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Configuration
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</title>
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<para>
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The good news is: on most systems PCI and USB based boards are
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configured automatically. The kernel will
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detect your data acquisition devices, will load the appropriate
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kernel drivers and will create the
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<filename>/dev/comedi</filename> entries.
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<screen>
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bp1@bp1-x61:~/sandbox/comedilib$ ls -l /dev/comedi0*
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crw-rw---- 1 root iocard 98, 0 2012-04-26 23:41 /dev/comedi0
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crw-rw---- 1 root iocard 98, 48 2012-04-26 23:41 /dev/comedi0_subd0
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crw-rw---- 1 root iocard 98, 49 2012-04-26 23:41 /dev/comedi0_subd1
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</screen>
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Usually these devices belong to the group <systemitem class="groupname">iocard</systemitem> as shown here. The only
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action you need to take is to become member of this group and
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then the &comedi; device is ready to be used.
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</para>
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<para>
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There are a few PCI drivers that for one reason or another
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do not support auto-configuration, either because there is
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more than one variant of a board sharing the same PCI device
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ID (e.g. Advantech PCI-1710 and PCI-1710HG), or because
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some configuration options are needed (e.g. Amplicon PCI224
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and PCI234) or for some other reason. It is also possible
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to disable auto-configuration when loading the
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<systemitem>comedi</systemitem> kernel module. In these
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cases devices need to be configured manually as for ISA
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cards. Conversely, most &comedi; drivers supplied with the
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kernel sources that support auto-configuration may no longer
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support manual configuration.
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</para>
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<para>
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By default, the <systemitem>comedi</systemitem> kernel module
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does not reserve any devices for manual configuration so
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manual configuration will fail. To allow devices to be
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configured manually, set the
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<parameter>comedi_num_legacy_minors</parameter> module
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parameter to the number of devices to reserve for manual
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configuration when loading the <systemitem>comedi</systemitem>
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kernel module. If using <command>modprobe</command>, this
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can be set automatically by editing
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<filename>/etc/modprobe.conf</filename> or
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<filename>/etc/modprobe.d/comedi.conf</filename> (depending
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on the system) to include the line:
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<screen>
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options comedi comedi_num_legacy_minors=4
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</screen>
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The number <literal>4</literal> in the above line may be
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adjusted to increase or decrease the number of devices to be
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reserved for manual configuration.
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</para>
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<para>
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Old ISA based cards need to be manually configured which is
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explained here. You only need to read on here
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if you have one of these old cards.
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On embedded systems it might also be necessary to load the
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driver and then to configure the boards manually.
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In general manual configuration is done by running
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the <command>comedi_config</command> command
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(as <systemitem class="username">root</systemitem>).
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Here is an example of how to use the command (perhaps you should read
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its <command>man</command> page now):
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<screen>
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comedi_config /dev/comedi0 labpc-1200 0x260,3
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</screen>
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This command says that the <quote>file</quote>
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<filename>/dev/comedi0</filename> can be used to access the &comedi;
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device that uses the <parameter class="command">labpc-1200</parameter> board, and that
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you give it two run-time parameters (<literal>0x260</literal> and
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<literal>3</literal>). More parameters are possible, and their
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meaning is driver dependant.
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</para>
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<para>
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This tutorial goes through the process of configuring &comedi;
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for two devices, a
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National Instruments AT-MIO-16E-10, and a
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Data Translation DT2821-F-8DI.
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</para>
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<para>
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The NI board is plug-and-play. The current <systemitem>ni_atmio</systemitem> driver
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has kernel-level ISAPNP support, which is used by default
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if you do not specify a base address. So you could simply
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run <command>comedi_config</command> as
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<screen>
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comedi_config /dev/comedi0 ni_atmio
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</screen>
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For the preceding <command>comedi_config</command> command to succeed, the
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<systemitem>ni_atmio</systemitem> kernel module must
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be loaded first. For plug-n-play boards on
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modern kernels, the appropriate comedi kernel modules should get loaded
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automatically when your computer is booted.
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The <command>modprobe</command> command can
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be used to manually load/unload kernel modules, and <command>lsmod</command>
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will list all the currently loaded modules.
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</para>
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<para>
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For the Data Translation board, you need to know
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how the board's jumpers are configured in order to specify the correct
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<command>comedi_config</command> parameters. These parameters for the board are given in the
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<link linkend="lowleveldrivers">kernel drivers</link> section about the <systemitem>dt282x</systemitem>
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driver.
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The card discussed here is a DT2821-f-8di. The
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entry for the <systemitem>dt282x</systemitem> driver tells you that the
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<command>comedi_config</command> parameters give the driver the I/O base,
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IRQ, DMA 1, DMA 2, and
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in addition the states of the
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differential/single-ended and unipolar/bipolar jumpers:
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<itemizedlist>
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<title>dt282x configuration options:</title>
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<listitem><para>[0] - I/O port base address</para></listitem>
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<listitem><para>[1] - IRQ</para></listitem>
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<listitem><para>[2] - DMA 1</para></listitem>
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<listitem><para>[3] - DMA 2</para></listitem>
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<listitem><para>[4] - AI jumpered for 0=single ended, 1=differential</para></listitem>
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<listitem><para>[5] - AI jumpered for 0=straight binary, 1=2's complement</para></listitem>
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<listitem><para>[6] - AO 0 jumpered for 0=straight binary, 1=2's complement</para></listitem>
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<listitem><para>[7] - AO 1 jumpered for 0=straight binary, 1=2's complement</para></listitem>
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<listitem><para>[8] - AI jumpered for 0=[-10,10]V, 1=[0,10], 2=[-5,5], 3=[0,5]</para></listitem>
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<listitem><para>[9] - AO 0 jumpered for 0=[-10,10]V, 1=[0,10], 2=[-5,5], 3=[0,5],
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4=[-2.5,2.5]</para></listitem>
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<listitem><para>[10]- A0 1 jumpered for 0=[-10,10]V, 1=[0,10], 2=[-5,5], 3=[0,5],
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4=[-2.5,2.5]</para></listitem>
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</itemizedlist>
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</para>
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<para>
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So, the appropriate options list might be:
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<screen>
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0x200,4,0,0,1,1,1,1,0,2,2
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</screen>
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and the full configuration command is:
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<screen>
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comedi_config /dev/comedi1 dt2821-f-8di 0x200,4,0,0,1,1,1,1,0,2,2
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</screen>
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Setting the DMA channels to 0 disables the use of DMA.
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</para>
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<para>
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So now you have your boards configured correctly.
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Since data acquisition boards are not typically well-engineered,
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&comedi; sometimes can't figure out if an old non-plug-n-play
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board is actually in the computer and at the base address you specified.
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If it can't, it assumes you are right. Both of these boards
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are well-made, so &comedi; will give an error message if it
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can't find them. The &comedi; kernel module, since it is a part
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of the kernel, prints messages to the kernel logs, which you
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can access through the command <command>dmesg</command> or the file
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<filename>/var/log/messages</filename>.
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Here is a configuration failure (from <command>dmesg</command>):
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</para>
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<screen>
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comedi0: ni_atmio: 0x0200 can't find board
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</screen>
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<para>
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When it does work, you get:
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</para>
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<screen>
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comedi0: ni_atmio: 0x0260 at-mio-16e-10 ( irq = 3 )
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</screen>
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<para>
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Note that it also correctly identified the board.
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</para>
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</section>
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<section id="gettinginformation">
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<title>
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Getting information about a card
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</title>
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<para>
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So now that you have &comedi; talking to the hardware, try to
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talk to &comedi;.
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Call the command <command>comedi_board_info</command>, which provides information
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about each subdevice on the board.
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Here's part of the output for the USB-DUX sigma
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board (which is on <filename>/dev/comedi0</filename>), as a result of
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the command <command>comedi_board_info -v</command>.
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</para>
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<screen>
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overall info:
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version code: 0x00074c
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driver name: usbduxsigma
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board name: usbduxsigma
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number of subdevices: 4
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subdevice 0:
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type: 1 (analog input)
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flags: 0x10119000
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SDF_CMD_READ:can do asynchronous input commands
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SDF_READABLE:subdevice can be read
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SDF_GROUND:can do aref=ground
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SDF_LSAMPL:subdevice uses 32-bit samples for commands
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number of channels: 16
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max data value: 16777215
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ranges:
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all chans: [-1.325 V,1.325 V]
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command:
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start: now|int
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scan_begin: timer
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convert: now
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scan_end: count
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stop: none|count
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command structure filled with probe_cmd_generic_timed for 16 channels:
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start: now 0
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scan_begin: timer 1000000
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scan_begin_src = TRIG_TIMER:
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The sampling rate is defined per scan
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meaning all channels are sampled at
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the same time. The maximum sampling rate is f=1000 Hz
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convert: now 0
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scan_end: count 16
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stop: count 2
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subdevice 1:
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type: 2 (analog output)
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flags: 0x00125000
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SDF_CMD_WRITE:can do asynchronous output commands
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SDF_WRITABLE:subdevice can be written
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SDF_GROUND:can do aref=ground
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number of channels: 4
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max data value: 255
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ranges:
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all chans: [0 V,2.5 V]
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command:
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start: now|int
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scan_begin: timer
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convert: now
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scan_end: count
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stop: none|count
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command structure filled with probe_cmd_generic_timed for 4 channels:
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start: now 0
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scan_begin: timer 1000000
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scan_begin_src = TRIG_TIMER:
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The sampling rate is defined per scan
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meaning all channels are sampled at
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the same time. The maximum sampling rate is f=1000 Hz
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convert: now 0
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scan_end: count 4
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stop: count 2
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subdevice 2:
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type: 5 (digital I/O)
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flags: 0x00030000
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SDF_READABLE:subdevice can be read
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SDF_WRITABLE:subdevice can be written
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number of channels: 24
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max data value: 1
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ranges:
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all chans: [0 V,5 V]
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command:
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not supported
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subdevice 3:
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type: 12 (pwm)
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flags: 0x00020100
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SDF_MODE1:can do mode 1
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SDF_WRITABLE:subdevice can be written
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number of channels: 8
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max data value: 512
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ranges:
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all chans: [0,1]
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command:
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not supported
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</screen>
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<para>
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This board has four subdevices. Devices are separated into
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subdevices that each have a distinct purpose; e.g., analog
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input, analog output, digital input/output.
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</para>
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<para>
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Here's the information from &comedi;'s <filename>/proc/comedi</filename>
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file, which indicates what drivers are loaded and which
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boards are configured:
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</para>
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<screen>
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cat /proc/comedi
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</screen>
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<screen>
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comedi version 0.7.76
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format string: "%2d: %-20s %-20s %4d",i,driver_name,board_name,n_subdevices
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0: usbduxsigma usbduxsigma 4
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usbduxfast:
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usbduxfast
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usbduxsigma:
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usbduxsigma
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</screen>
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<para>
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This documentation feature currently returns the driver name, the device name, and the number of
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subdevices. Following those lines are a list of the &comedi; kernel
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driver modules currently loaded, each followed by a list of the board
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names it recognizes (names that can be used with
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<command>comedi_config</command>).
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</para>
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</section>
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</section>
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