CODEWITHSUNDEEP
system-verilog
hops
hops

Reputation: 251

Interfaces without Modports

SystemVerilog interfaces have really simplified my FPGA designs. They allow me to route many signals to multiple blocks in logical groupings. I really like them. I use them with modports to indicate the in/out directions. In the two books I've read on SystemVerilog, interfaces are introduced and the syntax is shown before modports. At the end of the chapter/section, modports are introduced as a helpful way to use interfaces. As far as I can tell, I would never use an interface if the concept of a modport did not exist. So, this brings me to my question...

Are there usage cases for interfaces that make sense without using modports?

The usage case could be in implementation/synthesis or in verification/simulation. I'm mostly curious to learn something new here about interfaces. I looked for related questions but didn't see any.

Upvotes: 1

Views: 1009

Answers (1)

dave_59
dave_59

Reputation: 42698

modports are intended for tools (like synthesis) that compile a design with boundaries that require direction information. If you flatten out the hierarchy with an embedded interface, there's no need for directions. Simulation tools almost always do this, so interfaces used just for verification do not need modports.

Some people put modports in interfaces for verification as a way of restricting access to certain signals, but unfortunately, many simulation tools do not enforce the direction, especially when used with a virtual interface.

Upvotes: 3

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