topic Re: PCI 6220 linux in Driver Development Kit (DDK)

PCI 6220 linux

cfiene — Fri, 10 Feb 2006 14:56:26 GMT

I am working on an application specific driver to for the PCI 6220 under linux.
I have the DDK and visa lib installed. I am trying to get the aiex2 example working.
I get a clean compile, but the string argument to acqireBoard() appears to be wrong, or the installation is wrong.

The example come with the code as follows:
bus = acquireBoard( "PXI4::1::INSTR");

lspci -v for my system with the PCI 6220 installed is as follows:

0000:00:08.0 Class ff00: National Instruments: Unknown device 70b0
        Flags: bus master, medium devsel, latency 32, IRQ 11
        Memory at d2800000 (32-bit, non-prefetchable) [size=4K]
        Memory at d2802000 (32-bit, non-prefetchable) [size=4K]

I did find the document that tries to explain the string format, but nothing I've tried seems to work.
I coded the following and no combination worked:

    for( int i=0; i<16; i++ )
    {
       for( int j=0; j<24; j++ )
       {
          char str[80];
          sprintf( str, "PXI%d::%d::INSTR", i, j );

          bus = acquireBoard( str );

          if( bus != NULL )
          {
            printf( "found board at i=%d j=%d\n", i, j );
            break;
          }
       }
    }

Suggestions?

Re: PCI 6220 linux

AlanArmstead — Fri, 10 Feb 2006 19:08:01 GMT

Hello,
Could you give us a few extra pieces of information.
1) What Linux distro are you running?
2) You mentioned that you have NI-VISA installed. Which version do you have?
3) Are you using the NI-VISA OS Interface? (there are a couple different ones out there)

-Alan A.

Re: PCI 6220 linux

cfiene — Fri, 10 Feb 2006 19:20:56 GMT

1) What Linux distro are you running?
Suse 9.3 kernel 2.6.11.4-20a

2) You mentioned that you have NI-VISA installed. Which version do you have?
NI-VISA 3.4

3) Are you using the NI-VISA OS Interface? (there are a couple different ones out there)

yes as found in the nimseries.zip
as downloaded from links on:
http://digital.ni.com/express.nsf/bycode/exyv4w?opendocument&lang=en&node=seminar_US

Re: PCI 6220 linux

AlanArmstead — Fri, 10 Feb 2006 19:59:24 GMT

Ok, so you probably just need to add a like to visaconf.ini which is located here: usr/local/vxipnp/linux/NIvisa

Before the 'Aliases' stuff, add this line: ShowRegisteredDevOnly = 0

This should fix your problem.

FYI - the string passed to the acquireBoard function is a VISA PXI resource string. The format is:

PXI<bus_number>::<device_number>::INSTR

NI-VISA allows more complicated strings that allow you to specify the function number and other PCI attributes. The PCI bus, device and function numbers allow you to form a unique id for any device on the system.

The lspci output format for the location of the PCI device is:

where slot is the the device number. The format might change slightly between distros. For your device, my guess is that the string is PXI0::8::INSTR.

-Alan A.

Re: PCI 6220 linux

cfiene — Fri, 10 Feb 2006 21:49:45 GMT

Unfortunately, I still get the same results.

Stepping into acquireBoard I get the return status on viOpen
of -1073807343

Does this give any hints?

Re: PCI 6220 linux

AlanArmstead — Mon, 13 Feb 2006 15:48:23 GMT

Could you run visaconf and see if your device is found by that utility?

-Alan A.

Re: PCI 6220 linux

cfiene — Mon, 13 Feb 2006 15:55:47 GMT

visaconf only shows serial ports
Not the PCI 6220.

Re: PCI 6220 linux

AlanArmstead — Mon, 13 Feb 2006 17:02:09 GMT

Try unzipping this attachment and putting the .inf file in this directory: /usr/local/natinst/nipal/etc/inf

Alan A.

Message Edited by Alan [DE] on 02-13-2006 11:03 AM

Re: PCI 6220 linux

cfiene — Mon, 13 Feb 2006 20:13:22 GMT

That did it. Thanks!

Re: PCI 6220 linux

cfiene — Tue, 21 Feb 2006 16:54:03 GMT

Now I'm not getting reasonable data from the ddk examples programs aiex1.cpp and aiex2.cpp. I tie channel 0 to ground or a voltage and the readings don't follow.
Has anyone else got these examples to work?

Re: PCI 6220 linux

cfiene — Wed, 22 Feb 2006 15:37:47 GMT

ERR that should read UNREASONABLE data from executing aiex1 and aiex2 with the pci-6220

Re: PCI 6220 linux

AlanArmstead — Mon, 27 Feb 2006 23:28:49 GMT

How are you connecting your signals?

As they are written, the examples set up the analog input channels in differential mode. So, to read 0V on ai0, you should short ai0 to ai8 (connect pin 68 to pin 34 with a wire). To read a voltage source, connect ai0 to V+ and ai8 to V-.

-Alan A.

Re: PCI 6220 linux

cfiene — Tue, 28 Feb 2006 16:15:52 GMT

That was it. I had assumed it was ai0+/ai1- (pin 68/pin 33) not ai0+/ai8- (pin 68/pin 34).
There is nothing in the 622x specification pinouts to indicate differential wiring (page 11 Figure 1 of 371290d.pdf).
Still a bad assumption on my part.

Tying both + and - to aignd (pin 67) gets the reading down to a single bit of jitter, otherwise I'm getting about 4bits of jitter.