Writing SDI out NI 6120 DIO.

[JPO]

I need to write Serial Data out the Digital lines of my NI 6120.
I am using three of the digital lines as outputs.
D0 - CLK
D1 - Enable
D2 - Data

What is the best way to setup the NI 6120 to do what I am trying to do?
I need to get the CLK as fast as possible, but slower will work.
I am using Measurement Studio ActiveX controls with visual basic 6.0.
How can I get a clock out DIO?

Please let me know if you need more information.
Help is greatly appreciated.

Thanks,
John

[sergesl]

Hello JPO,

The DIO on the 6120 can be clocked at 10Mbps. However, you will have to implement the serial protocol yourself in software. You can set line 0 to be output and use it to clock. Then depending on what you serial protocol is and whether you are reading or writing, you will decide on the directions of the other lines.
If you provide more information about your serial protocol, I may be able to help you further.

[JPO]

Well, Ya I've 'bit banged' the protocol using software timing, but it only runs up to a few khz and it is not stable because of the scheduling of the Operating System. More importantly, I need to know the best way to provide hardware timed Digital IO.

Currently I'm timing the DIO with AOUpdate and writing arrays that describe the patterns I need.

The protocol is just a standard SPI port. Clk, enable line and data.

[sergesl]

Hello JPO,

SPI is a handshanking protocol and there is no other way that I know of to do this using the board you have. You have to respond to serial data and you can only respond in software.
There are other National Instruments devices that can allow you to build that type of communication in real-time though. I am talkin about FPGA devices. Checkout it out at http://sine.ni.com/nips/cds/view/p/lang/en/nid/14202.