Triggered digital read/write sequence

Question

Hello,
I'm fairly sure this is impossible to do in Labview but thought I would ask the question just in case:
On a digital falling edge I need to set one digital line on a PCI-6224 high and one low, then read sixteen lines as a port.  Next the high and low output lines should change status and then the sixteen lines should be read again. 
The process repeats on successive falling edges.  The time between edges may be as short as 11 microseconds (90kHz). 
We currently have a program written in C++ to do this job but I'd like to create something a bit more user friendly and have virtually no C++ experience myself.
Thanks.
Solved!
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Answer 1

Hi Simon,
I have an idea of how to do this using the DAQmx card.  This hasn't been tested but I believe this should work with just a few tricks with DAQmx.  There are three tasks that will be required:
Counter Output
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This should be a retriggerable counter task.  Take a look at the example in the LabVIEW example finder under Hardware Input/Ouput>>DAQmx>>Generating Digital Pulses>>Gen Dig Pulse Train-Finite-Retriggerable.
1. This should generate two pulses every time the external trigger is recieved so your 11us pulses are the trigger for this task.
2. These pulses are for each read of the digital lines so:
Rising edge - Changed the enable lines
Falling edge - Read the data.
By making these pulses wide enough (>140ns) this will take care of the settling time of the DO lines.
3. The gap between the pulses should be long enough for any delay require between reads.
Digital Output
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This should be a regenerative continuous output - see example Hardware Input and Output>>DAQmx>>Digital Generation>>Cont Write Dig Port-Ext Clock.vi.
1. The clock source should be set by right clicking on the source control.  Select I/O Name Filtering and then enable the advanced terminals tick box.  Then you can select the appropriates counters internal output.
2. You will need to set the clock edge to be the rising edge.
3. Prime the buffer with the two outputs we require e.g. 10 and 01 then sending a pulse to the clock will effectively switch between the two.
Digital Input
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This should be a standard continuous input task such as the example Hardware Input and Output>>DAQmx>>Digital Measurements>>Cont Read Dig Channel-Ext Clk.vi
1.Set up the timing VI almost identically to the output task.  Same source but this time clock on the falling edge.
2.Do with your data what you will!
Overall Program
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The main consideration is that you should start the counter output last as once this is running the others can start clocking data.
I hope this helps and is clear enough.  Let me know if it makes sense or if you need more information or even any help building this program.
Regards,
James Mc
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