Different Clock Timings for REQ 1/2 pins for PCI 6534

[dhruvish]

I came to know that REQ 1 and 2 pins can be used with different timings hence generate two different clocks. But when does the clock actually start? Is it @ power on or there is something like a trigger by software?

I am asking this because I want to apply the clocks generated by these pins to other boards (other 6534 and 6110) and use the trig1 pin to trigger every chip (including the one which generated clocks) after some clock cycles are completed and start Data Acquisition.

[Ames]

dhruvish,

From your description of the REQ1 and REQ2 lines I am assuming you are referring to Pattern I/O mode.

By default data transfer does not begin (clock doesn't start) until a software call (DIG_Block_In, DIG_Block_Out or DIO Start VI). However, you can setup a hardware start trigger.

Refer to Chapter 2 page 19 in the 653X user manual for information on deciding how to start and stop a transfer. Linked below is the 653x user manual:
http://digital.ni.com/manuals.nsf/websearch/EDE443F5C700373A862569B90072D26F?OpenDocument&node=132100_US

Ames
Applications Engineering
National Instruments

[dhruvish]

Yes, I am using the Pattern I/O mode. I have gone through the manual. Following is what I want to try to do.

Start the clocks (NOT DATA TRANSFER) one 10MHz and the other at 1.25 MHz. Provide clocks to second 6534 board and one analog board (6110). Now, trigger the the data transfer from all the boards at the same time using the pin named ACK (Starttrig) so that data transfers from each of them will be in sync. Since, the clocks are supplied by one of the boards, CLK edges should match with very negligible delay.

Now, Here are questions.

1. Can I externally trigger the 6534 board? I would like to trigger it form TRIG1 pin of Analog board (if I can supply that trigger to other boards??).

2. Can I internally trigger the 6534 board and supply that
trigger to other boards?

3. Do I have to specify any pre trigger data in or out. I dont want any pre trigger data.