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Help: Altera megafunctions, Quartus II

I'm an FPGA newbie, working with the freeware Altera Quartus II IDE. I used the megafunction builder to create a FIFO memory, the .v file it generated is similar to the virtual prototypes created for COM interfaces, with a data structure and no functions. Is this all that the megafunction builder provides, and I need to write my own Verilog code for eg. bumping the address registers and generating handshake signals? Or is that code generated for me already in a file that I haven't found yet? TIA

Reply to
Bruce Varley
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Quartus has a megafunction for a FIFO, it is under 'Memory Compiler' that has a typical FIFO interface set of signals. Which megafunction part are you using?

Kevin Jennings

Reply to
KJ

Megafunctions can instantiate internal FPGA structures - so the Megafunction .v just instantiates another module without any actual code, which looks like a prototype. The synthesis tool does however know about this and 'links' it with the right logic. The Megafunction header .v is mostly about declaring the right parameters to the internal module, and also saving the configuration (in comments at the bottom) so you can go in and edit it with the GUI next time.

As well as physical hardware blocks, Megafunctions can instantiate private Altera modules or encrypted IP, so you might not be able to see the internals. You can also ask them to make testbenches to try out the function in the simulator. I'd have a look at that first to see what the interface looks like (the manual PDF will also tell you).

Theo

Reply to
Theo Markettos

DCFIFO, double clocked FIFO. Using the wizard was straightforward, but after that I'm not sure whether I need to implement the glue logic, such as the memory address incrementing and rollaround. Sounds like I don't (once I work out what to do to make it happen).

Thanks for responses.

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