LabVIEW FPGA Idea Exchange

I often work with the FPGA in hybrid mode because the Scan Interface covers most of the project requirements 90% of the time.  When NI added support for the SGL datatype to the FPGA module in 2012 (?), they overlooked user-defined variables.  There is currently no built-in support for typecasting a SGL to U32, so passing SGL data back to the host requires FP controls or using custom typecasting solutions (see SGL typecast) on both the FPGA and host layers.

Please add SGL as an option for user-defined variables.

The loop timer express VI is very useful to time a loop to an exact rate, however... if you want to be sure the loop is meeting the rate requested... you also have to put in tic count VIs like this:

Since the loop timer express VI already is calculating how long it needs to wait in order to achieve the desired loop time, I would prefer it if at least output a bool that indicated it failed to achieve the timing required.

It would be best if it output the actual tics it waited in like I16 form so it could go negative (indicating the # of tics it failed to achieve timing by.

Perhaps there's already a good way to do this, but some structures/nodes are allowed in a Single-Cycle Timed Loop but their behaviour is significantly changed, perhaps breaking your VI.

It would be good to be able to mark VIs in some way as unsuitable for use within a SCTL.

An example is the flat sequence structure - you can place this in a SCTL and it can pass intermediate file generation, but the behaviour is as if there was no sequence structure.

Assuming that it isn't always superfluous, this probably indicates invalid behaviour but is not necessarily obvious to detect (e.g. with broken compilation or intermediate files).

Some specific node that could be placed on a block diagram and indicate that a VI cannot be placed inside a SCTL would be useful.

Something like a Divide can be used for this, but not trivially easily - you need to actually use the output of the Divide or else the dead-code elimination allows the intermediate files to be happily generated. It took me quite a few goes to get a failure even with SGL precision divide in a SCTL... wiring to a structure or an indicator is not enough, it must be something that actually uses the value.