arrays in the fpga module

[trajkan]

how long does it usualy take for a compilation when dealing with a pretty simply 1D array? I have been waiting for to hours and the compile is still stuck at "HDL Analysis".

[John Rich]

There are a lot of factors which will affect how long it takes. How large is the array? What else is going on in the program? How fast is the processor on the machine that you're using for the compile? Are you doing anything else on that machine while the compile is operating? In my experience arrays use up a lot of the FPGA resources and programs take a long time (hours) to compile on a 1.1 GHz PC.

[trajkan]

My computer is a Intel 3.2 GHz with 1 GB of ram. The array i tried to build only had like 100 elements and still it takes very long time to compile.

[John Rich]

I have had similar experiences with arrays and have found that 100 elements is a large array to compile for the FPGA. Is there a way to do what you're doing without using an array?

Perhaps others with more FPGA experience could chime in here.

Message Edited by John Rich on 06-01-2005 11:08 AM

[trajkan]

I want to send some analog signals through my FPGA and further on to my host VI so that I can monitor the graph obtained. I havent found a function in the Windows environment to do this (through the FPGA, ther is only functions considering NI-DAQ). I thought if I can make an array in the FPGA module and then send it further to the host VI for processing I could bypass my problem, but instead my VI compiles for a long time( actually I have never had the patience to wait more than a couple of hours). And by the way is there a function in the FPGA module To write data to a file, like in the Windows environment?

[John Rich]

What fpga are you using? The fpga itself has no data storage ability. With the cRIO systems you can save data to file on the controller using RT vis.

It's still not clear to me exactly what you're trying to do. Could you post an example of your code?

[trajkan]

I can send you the code tomorrow, because i am not at the laboratory at the moment. I can try to explain what i am doing.
I am actuating 4 valves to a combustion engine. every valve is equiped with a positioning sensor that gives analog signals to my FPGA(PCI 7318 or something). Now I want to monitor the signal from the positioning sensor in my host VI. How can I do this?

[DD]

Try reducing your array sizes to less than 10 elements. If this provides
too small a buffer for your monitors, try using the FPGA memory functions to
form the buffer. By using indices for next write and next read, you can
monitor your buffer so that your interface vi will be able to tell if you
have a data overflow.