don't care write on digital lines

[bhotu]

hi!

I want to write 0xxx pattern on digital lines. How can I write this pattern on digital lines? x meance don't care.

In attached .jpg files, I have written 0000 in place of 0xxx so please help me.

thanks

[RavensFan]

Does this generate any kind of errors when you run it?

It seems that you have created a analog voltage channel for writing to a digital output line.  It created an error for me when I tried to copy the code and run it.

[bhotu]

hi!

I am sorry, I forgot to change the Digital Output. So, please read Digital Output in place of AI Voltage.

Thanks

[MickeyD]

Hello,

I was making your code and you were able to write 0000 according to your post.  If this code does not perform the way you need then how does it behave, and what would you rather it did.  I can manipulate four LEDs and see them set to on and off.  Do you not want to set the first 3 line values?  If you could get back to me and tell me what you want, I just don't see why you need to write a value on line 3 and not care about lines 0 to 2. Please get back to me,

Have a great day,

Michael Denton
Applications Engineering
National Instruments

[Broken_Arrow]

Doesn't this fall into the often requested Tri-State boolean area ? Perhaps the user requests that the lines that have not been written to are not 0 "yet".

[Dennis_Knutson]

Or is he asking for something like the line mask input on the old DIO Port Write?

[bhotu]

hi!

Thanking you for your reply.

I want to use decoder in my circuit. Decoder works like E b2 b1 b0. if E is 1 than it selects input from 000 to 111 with resp. b2 b1 b0. if E is 0 and b2 b1 b0 is xxx meance 0xxx than it is Tristate.

so I want to write 0xxx in my initial stage of program so my decoder works as tristate. if i would not write this data on DIO than if E would be 1 that time so it will select any input and my program will work misbehaviour.

My question is how to write xxx on DIO. because initial value of data lines are 1 or 0.

Thanks

[TCPlomp]

Create a task for each line!

Ton

[MickeyD]

Hi,

I attached a VI to set your port up as tristate.  If you don't write a value to those lines, then they should remain tristated.  I will check and see if this is not the behavior I find, but let me know if by using this subVI and setting your port to tristate, can you then get the behavior you want.

Thanks,

Michael

[Enrique]

Sorry to jump in, but I am reading this and I don't see the problem. Instead, I see a little confusion about what "don't care" means. It is not that you are going to write "xxx" in your digital line. It is that when E = 0, b2 b1 and b0 are irrelevant. So, you should see the right result it doesn't mater if you write 0000, 0111 or anything in between. As long as E = 0 you should see the same result in your decoder no matter the values in b2 b1 or b0. If you are seeing differences, then you have a problem on the decoder.