Adrenaline

Global Variables work very well for transfering data within the FPGA. You want to stay away from Local Variables becuase those require a Front Panel control, more FPGA space is required to work with the RT host. The biggest issue you will run into is race conditions with using Global Variables if you have more than a one loop writing to the variable. Arrays are okay on the FPGA as long as you keep the element count low. An array of 4x8bit integers will take the same fabric as a 32bit integer. I have not used FGPA memory becuase the latency was not acceptable in my application. One thing to be aware, try and minimize FPGA I/O nodes. They take a lot of space on the FPGA, try and use less than 6 "nodes" with any number of elements. I have 32 loops that each set a digital output seperately. I had to use a global boolean for each loop; then have another loop read all 32 global booleans and build an array to output to the digital output card. Because using 32 I/O nodes didn't fit on the FPGA.

The FPGA can only complete one read per clock cycle. The only thing to do is read from in a loop that iterates N times and have the tunnel build the array. Any loop will work the For loop lends itself best to this sort of thing. The array size must be constant, if you are trying to read different sized arrays some elegance will be needed when you self build the array.