csn not latching in IOB

[AnttiLukats]

on my workstation with own toplevel I see warning that CSN is not registered in IOB (the other signals are).

I am using not this code from here, but the code from MEGA65 fork...

p_fsm : process (clk_i)
begin
if rising_edge(clk_i) then
hb_csn_o <= '0'; -- added by Antti
hb_rstn_o <= '1';

when I add the above line then CSN registers in IOB and design still works!
not sure if that is proper fix or not.

[MJoergen]

This is strange. I've just added your BUFR fix to this repo (copied from the MEGA65 fork) and rebuilt. The design works fine (as others already have reported).

However, I see no problems with the CSN register, see the following screen shots:


The CSN register is correctly placed in the IOB.

The line you added should not make a difference. I tried both with and without that line, and there is no change in behavior for me. Both with and without the design builds without any warnings related to IOB.

Are you sure your source code matches mine? I'm testing with commit 7068c29 in this repo. Are you able to share your toplevel code and constraints, perhaps in e-mail?

[AnttiLukats]

strange, on my PC it makes a difference, double checked the flow. I used the files from mega65 repo, not from here. But I think adding my added line is SAFE so why not add it?