Modify the AXI interface of FINN Stitched IP

[laochonlam]

Hi FINN developers,

I want to integrate FINN Stitched IP with my Vivado design. However, I found out that the FINN IP's AXI-Stream interface doesn't expose the tlast and tkeep interfaces. May I know what is the best way to modify the interfaces in order to integrate them into my Vivado design?

Thanks,
Lam

[heborras]

Hi @laochonlam,

exposing tlast is indeed possible using the InsertTLastMarker transformation:

finn/src/finn/transformation/fpgadataflow/insert_tlastmarker.py

Line 38 in d1cc9cf

class InsertTLastMarker(Transformation):

This must be done after the FIFO depths have been set. A bit of a convoluted example of this use-case can be found here: https://github.com/fastmachinelearning/finn-examples/blob/e36659647cc799dd44c7bd12b8be20df487fe55c/build/kws-pynqz-axidma/build.py#L51

However, as far as I know FINN does not implement the tkeep interface.

Cheers,
Hendrik

[laochonlam]

Thanks for letting me know it!

[JPPalacios]

Hi @heborras @laochonlam ,

Is this still applicable? I am doing something similar but working on the latest version of FINN. Thanks!

[heborras]

Hi @JPPalacios
this appears to still be applicable, as far as I can tell from a quick look at the current FINN source code on main, here:

finn/src/finn/transformation/fpgadataflow/insert_tlastmarker.py

Line 37 in 9d29968

class InsertTLastMarker(Transformation):

As in the transformation still exists and is still supposed to do the same thing. Note though, that I haven't used the feature in recent years, so your mileage may vary.