Acquire serial binary message after pulse with 6534

[joneff]

Hi,

Still not too familiar with PCI 6534 we got. Here's what I need to do:

1- Generate a 200nS pulse that will request a 112 bit of serial data to be generated from an external circuit.

2- Read the serial data: one data line, one clock line.

3- Do that again, at a rate of 2KHz if possible.

So my PCI6534 has one output (the trigger I need to generate) and 2 inputs (data in, clock in). Worst comes, the trigger could also be an input, generated by an external circuit, so it would simply reset my 6534 and tell it to "wait for the serial data to come, 112 bits". Also, if the trigger is a square at 2KHz and not necessarily 200nS long this could be ok, I could build a monostable circuit to compensate.

I played with the card before posting, was able to acquire pretty fast, generate a pulse although I did not seem to be able to control the rate, I was always at 20MHz or something like that.

Did somebody do something like that before? I would appreciate getting something to work and really understand also why it worked and how to best setup my 6534 to perform these tasks.

Thank You

jf

[joneff]

... forgot to mention, I'm using Labview 7.1...

[Marni]

Hello Joneff,

Are you using serial communication like RS232? If you are, it's much easier with a serial card. If you have to do it with a DAQ card, I have an idea of something to try to make the pulse 200ns. To create the digital pulse, use Write Dig Chan-Int Clk-Dig Start.vi from the Example Finder. (Help menu>>Find Examples - browse Hardware Input and Output>>DAQmx>>Digital Generation). Output a signal of 111111000000 (will get errors if its not 12 bits). Ideally you would set the scan rate to 30 MHz (1/200ns *6), but the PCI-6534 has a maximum of 20 MHz.

If you are not using serial communication like RS232 and you are just streaming in 112 bits of data, you can just do a triggered digital input. Please let me know if you have any questions. Have a great day!

Sincerely,

Marni S.