I am using the cRio-9012 with 8 ni 9401 modules in the chassis. I have two of those modules that are connected to an 16 bit data lines. These data lines are used for both input and output. I can write input data to the device connected to 9401 modules. The device responds by setting data on these lines is there a way to release the inputs to allow the connected device to control the data lines. I am not using all of the ni 9401 modules in the chassis. If there is a way to release the lines then I can wire the unused modules to read the data. My software version is Labveiw 8.5
I'm trying to do data communication between the cRIO and my device. I need to read and write to the same 16 data lines. When I write to the data lines the values 1 or 0 is held until I do another write. I need to set the data lines wait a 10 clock pulses the releases the 16 data lines to allow my device to write data on the lines.
From what I understand, you are trying to make your modules bidirectional so that they can accept both input and output, thereby preventing you having to do writes every time you want to do a read. The 9401 is a bidirectional module and be configured for bidirectional line measurements using four-bit nibble. You can have all input, all ouput or one nibble as input and the others as ouput--basically combine them whichever way you want. Please refer to this knowledgebase article on how to configure the nibble bits. Hope this helps.
Yes that is what I'm trying to do I didn't describe my problem well. When the NI 9401 is configured for output it provides the 5 volt TTL high signal providing the source. After I write the data with the Ni 9401 configured as a digital output is there a way to disable the source? The digital output is holding the data lines to the previous write values and when I read the same data lines with a different ni 9401 module set as an digital input I recieve the data that I just wrote. I have tried turning the ni 9401 set as digital output to input after I write the data but switching between the input and output is to slow. Is there a different module or software/hardware solution that can do this? I apologize for not describing the problem better.