Problem of Acquisition Data using PCI 6541

[titibena]

Hi all,

I have a problem in performing the acquisition data as described below:

1) I sent a burst command to UUT for reading data (on PCI 6541 card #1).  Ex: a command to read 10 data

2) UUT will respond by sending:

     a) the requested data which is not in 1 continous burst; Ex: 2+3+1+4

     b) a Rd_Clk which is connected to the STROBE pin of the 2nd PCI 6541 card 

     c) A Data_Valid signal;  Active "high"

My test setup is :

1) PC with window XP

2) LabVIEW 8.0

and my different test sequeneces are:

1)  I use Data_valid rising_edge as the "Pattern Match Start Trigger"  with number of sample =10

      --> in this case the acquisition data is not completed and contains both Valid & Invalid data

2)

  a) Data_valid rising_edge for "Pattern Match Start Trigger"  followed on by

  b) Data_valid "1" for "Pattern Match Reference Trigger";  To sampling only when data is valid

  --> In this case I got an Error indicating LV is still waiting for the samples to become available

3)

  a) Data_valid rising_edge for "Pattern Match Start Trigger"  followed on by

  b) Data_valid falling_edge for "Pattern Match PauseTrigger";  To stop sampling when data is invalid

  --> I got almost the same acquistion data as in test sequence #1 above.

What should I do to capture only the valid data?

Thanks

Hai.

[Ryan_M]

Hai,

It sounds like you only want to sample data when your UUT is driving the "Data Valid" signal HIGH.  If this is the case then I would recommend using this signal as an active LOW Pause trigger.  With the acquisition running, if the UUT holds this line LOW, the 6541 will not store data into its onboard memory.  When the UUT asserts Data Valid, the 6541 will start to store data into memory.  If the trigger drops low in the middle of the transmission, the data will be paused.  In this fashion you can throttle the data before it gets stored into memory and as the acquisition is executing.

[titibena]

Hi Ryan,

Thanks for the help.  I did the modification as you suggested and it works well

Hai

[Ryan_M]

Hai,

Glad to hear it!  Let us know if you run into any other questions.

Have a great weekend.

-Ryan Mosley