LabVIEW FPGA Idea Exchange

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The first thing you hear about programming FPGAs with LabVIEW is: use single-cycle loops. But if you build a state machine (while-loop + enum + case structure), in many cases you cannot make the outer while loop in a single cycle-loop, because not every state fits into a single-cycle loop. Therefore you have to place the single cycle-loop into every case, which has to run in one cycle, which takes up block diagramm space and is cumbersome. Therefore my idea to create a single-cycle case structure: it uses the same compiling mechanism of the single-cycle loop on every case, which is capable of running inside a single cycle. It would be nice, if this behaviour is configurable, meaning I can decide from case to case, if it is a single-cycle case or not. Some kind of right-click menu options like these: "make this case single-cycle", "make every possible case single-cycle", etc. Of course the mode of the case (single-cycle or not) should somehow be displayed.

Regards,

Marc

Select in SCTL

Initially I looked around for my previous idea here: Selecting between two I/O refnums not allowed because I thought it was the same and intended to post a comment to that, but I see that was a bit more specific.

This seems like a more allowable case - why is A forbidden and B perfectly ok?

Select node in SCTL

Case Structure to choose between two values based on boolean input

Here A is forbidden (at Intermediate file generation - so perhaps this would help: Unsupported nodes inside for loop within SCTL should result in a broken VI (NXG != Already Implemented really...)) but B is compiled with no problem. I really don't see why Select of two integers is different to a Case Structure with two integers input, a boolean case selector, and an integer output from the two inputs...

As an idea rather than a rant, I'd like A to be possible.

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Smart compilation

Hi there,

I got following feedback from a LV FPGA user:

When developing a FPGA application in LabVIEW, after submiting a FPGA code compilation - usually quite a lengthy process - if you modify the code either on the Front Panel or Block Diagram while compiling is in progress, this results in a Compilation Error at the end.

And this occurs regardless the modification be only a mere cosmetic change, without any implication in the code that is being compiled.
This is quite frustrating when you realize that the compilation has failed (maybe after half an hour waiting) just because you unconsciously clicked and resized some control or node.

In such a situation, when LabVIEW detects a code change while the FPGA compilation is running, it should warn the user with a message box; if the user confirms the code change, the current compilation can be inmediately aborted or let it continue (at user option); on the other hand, if the user cancels the modification, nothing happens and the compilation continues to a successful (hopefully) end.

Thanks

Álvaro

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Hello,

For the moment, there is only one clock assigned with the FPGA main VI. "The top level clock"

This clock is used by the code created on the main block diagram. (Outside SCTL)

Today, if you need an other clock ... you have to use SCTL's ... but using SCTL generates many problems, because not all instructions are allowed in SCTL's !

I think that XILINX can handle a kind of partition !

My need would be, for example, to have one partition running at 40MHz ... and an other at 80MHz ... without having necessary to use SCTL's.

This is only an idea ... i think that behind my idea something heavy must be done !

The Top would be, to be able to share data between the different partitions (using FIFO for example) ... but i think this is one more difficulty !

The partition mechanism could be created in Labview FPGA as follow ...

With multiple top VI's : On per partition
Or, with a special structure in the main vi block diagram : Partition structure, with a clock as input : Like a mega SCTL, without SCTL limitations.
Or, by adding a clock input to the while loops
...

Thanks for reading.

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As somewhat an opposite request to this idea

https://forums.ni.com/t5/LabVIEW-FPGA-Idea-Exchange/Ability-to-define-datatype-of-Registers-FIFOs-from-code-without/idi-p/3123936

I would like to show some pertinent information to the configuration of certain primitives in FPGA code.

The ability to turn this display on and off just like a label would be very welcome indeed. I'd always have it visible.

I just spent two days tracking down a bug which ended up being an under-dimensioned Block RAM instantiation (and how BRAM indexing works, just throwing bits away instead of coercing the read/write index), something whose configuration is completely hidden from view. Why can't we have some visible elements to show the size of a Block RAM and the Datatype (FXP would do for any given FXP type). Same goes for FIFOs, whether a FIFO is 16 elements or 8192 elements deep is a very important piece of information. And of course I mean only the primitives which instantiate the resources, not FP references for these items, even though the datatype of these would also be a very welcome addition.

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Pipeline structure

My original problem was that I in the FPGA have an array of data, where I need to do some calculation, where the only appropriate way was to use a pipeline. The pipeline is a very strong tool in the FPGA, but I think the LabVIEW tools could be changed so the pipeline is easier.

My old implementation if the pipeline:

Suggested implementation of single cycle pipeline, with shift registers in the tunnels, so all the code is run on each of the 5 elements in the array.

Maybe there should be added a number of iterations (like the “for loop”), if the number of data, is not defined by the array size.

In another project I have a continuous running pipeline, I have implemented in different ways, but one simple is as shown:

Before

Here the new pipeline sequence could also be used, maybe like following:

Here it should be stated in the loop tunnel, that the input data is read continuous.

Here I have shown in both examples, that it should be single cycle times loops, but maybe the pipeline structure should also be able to run with another timing (determined by the slowest frame).

I have seen the idea about the timed frame, it will help on the last example, but there will still be need for a pipeline structure.

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Basic building blocks

Basically I want a VI like open FPGA VI ref which takes a RIO interface and returns a reference, except that it doesn't deploy a reference if one doesn't exist. It would instead pop out a boolean or error if you try to get a reference and there is no bitfile already deployed.

Two use cases I have in mind:

-Imagine if you need a cRIO to start working ASAP so you deploy your bitfile to flash and tell it to run on power-up. You still have to package the exact same bitfile with your RTEXE, even though its already deployed. This increases the size of your RTexe significantly. Lets say you version your RTexe and don't version the FPGA deployed to flash. Depending on what the signature check is, obtaining a reference to your bitfile may cause the "new" bitfile to be redeployed, eliminating the advantage of loading your bitfile onto flash in the first place.

-Imagine if you have a framework like veristand where you need to use a single bitfile in multiple locations which were written by different developers and possibly released at different times. The tools on NI labs (https://decibel.ni.com/content/docs/DOC-35574) help a lot and let you, once you have a reference, confirm the reference has all the interfaces you need to run your code. However, if you need to share references between code modules you must still be sure to obtain it in just one place and then share the reference yourself using a global or FGV.

Having the RIO driver solve this would be very helpful.

Run-Time Dynamic Dispatch Support

The LabVIEW FPGA module has supported static dispatch of LabVIEW Class types since 2009. This essentially means all class wires must be analyzable and statically determinable at compile-time to a single type of class. However, this class can be a derived class of the original wire type which means, for instance, invoking a dynamic dispatch method can be supported since the compiler knows exactly which function will always be called.

http://zone.ni.com/reference/en-XX/help/371599H-01/lvfpgaconcepts/fpgaclassesinvis/

This is not sufficient for many applications. Implementations that require message passing or other more event oriented programming models tend to use enums and flattened bit vectors to pass different pieces of data around on the same wire. All of this packing and unpacking can automatically be handled by the compiler if we can use run-time dynamic dispatch to describe the application.

We call for the LabVIEW FPGA module to add support for true run-time dynamic dispatch to take care of this tedious, annoying, and down-right boring job of figuring out how to pack and unpack bits everywhere. Whose with me?

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Hi, since there an be a queue for compiling FPGA code, it seems natural to me to also be able to make a queue for generating intermediate files.

I'm working with 10 build specs. for compilation per project and generating intermediate files for my design takes aprox. 3-4 minutes. This means that I need to sit by my computer for half an hour just waiting and clicking build on every build specification. Sometimes I work with FPGA VI which need to build intermediate files for something like 7-10 minutes, so this is a pain.

It would be great if there was a way of just highlighting all build specifications for compilation with shift and just creating the intermediate files for them automatically one by one.

Can this be done?

I am currently running into this issue where I have some constant data I'm trying to write to some DO lines. I want this data to be a constant array on my block diagram, so I create the array programmatically under the "my computer" target. I then change the indicator that is populated to a constant and move it to the FPGA. When I right click and set the array to be a fixed size, it replaces all my data with 0's. I propose the data should not be cleared if I set my fixed array size to be equal to the size which the array already is.

Build Selection option

Sometimes I just want to compile a lot of Bitfiles (Be it for a release or a debugging test case) and I have to right click each and every Build spec and choose "Build". then wait about 10 seconds and do the same again for the next build spec.

How about being able to select multiple build specs and then select "Build Selection" and have time to go for lunch while the PC queues up all the compilations?

I don't use a compile farm and everything is done locally but at least the queuing could be automated.

Shane.

FPGA FIFO and Memory Editor

I have been working with FPGA for quite a while, and realized that manually opening and editing DMA, Target Scoped, P2P, VI scoped Memories, and project scoped memories can be very tedious and time consuming. Wouldn't it be great if there was a way to edit FPGA FIFOs and Memories from a single place. This notion gave birth to the FPGA FIFO Editor and FPGA Memory Editor. These editors would give the ability to see, create, remove, and edit FIFOs or Memories for that specific project (list both project and VI scoped items). Furthermore, their could be some additional logic built into the Editor that would alert the user when they have tried to configure something incorrectly (for instance an R Series target only has 3 DMA FIFOs, alert the user when they have configured more than that).

Listed below is a mock-up of the FPGA FIFO Editor.

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Default data type Fixed Point (FXP)

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When you configure Memory in LV FPGA, there is no way to find specific references to particular memory blocks using the search function. The search will show "ALL" memory access nodes, not just the ones you are looking for. Additionally a text serach will not catch the text from the X Nodes. This can be particularly tedious if you have many nodes in your hierarchy and are looking to only see references to a particular memory block.

I would like to see the search improved to allow filtering of the memory nodes the same way that we can search for global variables (find definition and find references)

LabVIEW FPGA Idea Exchange

Configurable single-cycle case structure

Select in SCTL

NI Cloud Compile Farm: take advantage of cached cores

Smart compilation

Fix tha latch point for FPGA property nodes

Multi top clock, for main VI ... Multi partition FPGA code ...

Show some important resource data on FPGA items (Block RAM, FIFO etc.)

Allow access to multiple IO registers at once like on certain DIO modules

Drive a host timed loop with LabVIEW FPGA IRQ

Pipeline structure

Basic building blocks

Track Device Utilization Over Multiple Compilations

Get reference to currently deployed bitfile on FPGA target

Run-Time Dynamic Dispatch Support

Lets enqueue creating intermediate files

Changing to a fixed size array shouldn't remove array data

Build Selection option

FPGA FIFO and Memory Editor

Default data type Fixed Point (FXP)

Improved Search Scope for IO and Memory X-Nodes