Interconnect PCI 6534

[Vishal]

Hello friends, one confusion is there. Pls help me to solve it.

I have two systems having pci 6534 in both of them.
Can I interconnect them using a single SH6868 cable?
As per me it may be harmful for both of the systems because it will short the VCC of both the systems.
It will short the DPULL & CPULL lines also.Will it create any problem?

Onw more question related to a vi of labview.
In DIO config.vi andshaking parameters input is there. In that REQ polarity can be used to specify the rising or falling edge signal in pattern input output mode.There are 3 options Active High,Active low & no change. In labview no change is given as default input. But what it means exactly. Please describe it briefly.

[rgharrison]

Hi Vishal,

Typically the Vcc and the GND of two different computer systems are different in potential. This will cause unwanted currents down the signal lines and could affect the acquisition of your data. There is also a small possibility that the currents could harm the circuitry of the board. So, in general, it is not recommended.

Yes, in pattern I/O mode you can use the DIO Config.vi handshaking parameters to alter the polarity of the REQ line. Although the title implies that the parameters are only used in handshaking mode, they are also valid for pattern generation/acquisition. You can specify whether you want the REQ to respond on rising edge or falling edge. The default is for rising edge and "no change" will not alter this parameter.

Usual
ly, when I am communicating between two 653x devices, I will generate data on the rising edge of the REQ signal and I will acquire data on the falling edge to ensure that there are no race conditions occuring. This is possible since the data travels down the cable at slightly different speeds.

Anyway, hope that helps. Have a good day.

Ron