PCI-6534 output modes

[Lei Dai]

Hi,

I know that the 6534 can output data that's been stored in it's memory but can it do this and run a program from LabVIEW at the same time (a simple case statement) ? I'm loading waveform data into the buffer and having it clocked out at 10MHz. I also need a timing signal that tracks the clock for 19 cycles, goes to logical hi for 21, then repeats. Since the clock signal changes state during each cycle, I can not store this timing signal alongside my data because I need 50ns resolution. Can anyone think of another to implement this timing signal?

Thanks,
Lei

[Ben]

HI Lei,

Double check my math on this.

If you double your clock, that will give you the 50ns resolution you need.

Of course your buffer will now have to be twice a large because you will need two values for each of the 100ns time slices you had before.

Now if you would concider buying a board that has some timers, you could configure them to take care of this other task and leave the 6534 to do it thing.

Is this of any help?

Ben

[KBersch]

I'm not sure what you're trying to do here. The 6534 doesn't "run" any LabVIEW programs, that,s what the computer it's attached to does.

The 65345 has two clocks and two I/O groups that are independant of each other. That might help. How are these two signals related? You say the timing signal tracks the clock (is that the 10MHz clock?) but then you say you need 50MHz resoloution, which you can't get tracking a 10MHz clock. Could you explain this a little better, please?

Kelly

[Ben]

Does the 6534 have Clocks?

This would trivila if there are clocks available.

One could count and roll-over to trigger the second etc.

Does the 6534 have clocks?

Ben

[KBersch]

The 6534 has "clocks" but no counters. The 6534 can output two seperate clocks at selected frequencies up to 20 MHz. I say "selected" because the frequencies are somewhat limited. The clock outputs are TTL.

Kelly

[Ben]

There's my dislexia kicking in again.

You said Clock, I read counter.

Ben

[Lei Dai]

Excuse the convoluted wording of my original post. I'll try to explain it a bit better. I meant that the timing signal needs to have 50ns resolution, as in, it needs to switch logic levels within 100ns (10MHz). For the first 21 100ns cycles, it needs to oscillate in sync with the 10MHz clock, then it needs to stay at logical hi for 19. My data is being clocked out by the 10MHz clock. The waveform data will consist of 21 cycles of data and 19 cycles of constant low. The timing signal must accompany this. It would be nice if I could store both signals alongside each other and output them in parallel but I will only have 100ns resolution at 10MHz. I was wondering if I could run a simple case statement (if <21, output clock, if >21, go to hi) while the board is
clocking out the waveform data that's stored in the buffer.

[KBersch]

If you used a trigger to start both at the same time you could use a 10MHz clock for the data and a 20MHz clock for the timing signal. I'm not sure how accurately the two would stay in sync. The timing loop in LabVIEW won't be accurate enough. The 6534 has two groups, each with an independant clock, that can be used simultaneously. The trigger ought to work. Not sure what to trigger on, though. Maybe you could trigger on the first clock going high? Or have LabVIEW set one of the unused lines high and trigger both on that.

Kelly Bersch
Anadigm, Inc.

[Ben]

If the answer to either of the follwing questions is Yes then disregard.

Are you using more than 1/2 your 32 Mb?
Are you using all 32 bits?

If not, double the clock and stuff the timing signal in along with the other wforms.

Ben