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VXI and local bus problem (long post)

Question asked by VRFuser on Dec 3, 1997
Hello all

I am currently working on a data acquisition project where we are using
VXI cards with local bus. The mainframe contains the following cards,
arranged from left to right:

1 x E1433 VXI digitizer with DSP with 4 channels
1 x E1432 VXI digitizer with DSP with 16 channels
1 x E1432 VXI digitizer with DSP with 4 channels
1 x E1562E VXI data disk

We are using HP-VEE 4.0 to set up a data acquisition using all three
digitizers. Data is to be transferred to the disk using the local bus.

The two E1432 cards are addressed together, meaning that they can be
viewed as a single logical E1432 having 20 channels.

It is crucial that we know which disk blocks correspond to which blocks
of samples, i.e. whether a given block of data was acquired by the E1433
or the E1432's. To achieve this, we will adjust the clock frequencies
and/or block sizes of the E143X cards.

The E143X  cards are programmed using the e1432 plug and play driver,
while the E1562 disk is programmed using direct I/O.

The first card (E1433) is set up to generate (MODE_LBUS_GENERATE) data
on the local bus. The E1432 (accessed as a single logical E1432) is set
up to append (MODE_LBUS_APPEND) its data to what data it receives on the
local bus. The E1562 (disk) is set up to consume data from the local
bus.

Now for the problem:

When using the set up as described above, we have a problem writing data
to the disk. The SCPI command sequence SEQ1:TRAN? indicates that a block
of data has been transferred. However the E1562 front panel indicates
that the disk is still waiting for more data, i.e. the green diodes are
constantly lit. When we retrieve data from the disk, it is obvious that
no new data has been written to it.

When performing the same test but only using the (pair of) E1432, data
is written to the disk and there are no problems. In this case the E1432
is setup to generate data on the local bus.

We have established that the cards are all functioning properly, and
that all seem to be intialized and correctly set up. The local bus is
enabled in a left to right fashion.

It would seem that the problem is either related to the local bus setup
(E143X setup) or to the E1562 setup.


I'm hoping that someone here has some experience using the local bus or
the E1562 and could offer us some advice.


Thanks for your patience.

Best Regards,

John Sletten,
Independent consultant
Oslo, Norway
Tel: +47 920 37050


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