userWarning regarding HWH file!

I tried to follow the following video creating a simple adder IP and accessing it in Python :

I get a userWarning: Users will not get parameters / registers information through TCL files. HWH file is recommended.

On the adder IP example after executing :

from pynq import Overlay

overlay = Overlay(‘/home/xilinx/pynq/overlays/adder/adder.bit’)


IP blocks

I added xadd_hw.h file in same location as the adder.bit and adder.tcl files. I did not change the name of the xadd_hw.h but still get the same warning as above !

Hi you should simply copy the hwh file (with the same name as the bitfile) to the same location of your bitfile. so not the header file, the hardware file.

it should be located in .srcs\sources_1\bd\design_1\hw_handoff\design_1.hwh in your vivado project


Just to add, you need to make sure the .bit and .hwh filenames are the same.
It is just a warning. You can use .bit + .tcl.
The warning is because the HWH includes more info about your design than the .Tcl so is more useful and the recommended way to use PYNQ.


Thanks Frank & Cathal.

It all works fine now. Your help is appreciated

The .hwh is also required otherwise IP blocks is reported as none ie with .hwh in place too (in my example adder.hwh), IP blocks for the adder example is the scalar_add block as expected. Therefore it has now found my scalar_add block & associated the defaultIP driver to it.

Managed to get the simple adder working now.

I connected yesterday with Jeff Jonhson (the author of that tutorial) on LinkedIn and reported this this morning & he will be adding it to his tutorial to help others carry on.

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