How does the digital data send out through DAQ, serial or parallel?

[Kevin_Price]

Sorry, I have absolutely no background in anything related to Active Matrix or pixel circuits, so I still don't really understand what you need from a signals and timing point of view.  Here are some basics:

- if you need to do hardware-clocking of any digital signals, you will need to supply an external sample clock.  Your board supports "correlated DIO", but cannot generate its own sample clock for digital tasks.   A counter pulse train is a common way to provide such a clock.

- If you have multiple digital pins/signals configured in a task, each *sample* of that set of signals will be generated simultaneously in parallel.

- If you need a timing sequence in which an individual signal changes digital state at specific instants in time, you will need to configure with an external sample clock as described above

- the two can be combined to make a kind of "matrix" where a given set of 4 digital states are output simultaneously as a single sample, but the other dimension of the matrix represents the states of those signals as a function of sample #.   Such a "4x4 matrix" of digital values would involve configuring with 4 digital lines in the task and 4 samples being generated.

-Kevin P

[crossrulz]

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@leo321 wrote:

I set labview to generate 4 different digital data through 4 lines. So they will be sent in serial way, right? If wait is set as 800ms, 1-1-1-1 each digit will take 200ms,right?

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NO.  All of the lines in the port will write their respective values at the same time.

And you really should not be creating multiple threads for the same issue.  You are just going to get fragmented discussions.

[leo321]

Dear Kevin_Price,

Thank you for your reply!

As to a counter pulse train:

1. How can I generate and configure a counter pulse train? With MAX and creating a task of counter, right?

2.According to your reply, if I need to supply an external sample clock, I should create a task of a counter pulse train, right? What should I do after that? For example, if I set PFI 12 is the counter pulse train, the source of DAQmx Timing should choose PFI12,right? Do I need to wire the PFI12 to the outside chips or breadboard?

3.I have tried to set the counter pulse train with half high time and I set it as the source of DAQmx Timing, but the code or labview won't run according to the time I set, what can I do to deal with it?

Thanks a lot!

Best,

Jason

[Kevin_Price]

Here's one example in LabVIEW of using a counter pulse train as a sample clock for a digital output task.   If you're programming in a text language, I'm afraid I don't know the syntax well enough to guide you in any detail.

I don't know if your external circuits also need the pulse train signal wired into them.  Do they need a clock signal that tells when digital samples are being generated?  If so, then yes.  If not, then no.

-Kevin P