Alessandro Comodi

Hi @slayer321, basically the bitstream tools in [here](https://github.com/SymbiFlow/prjxray/tree/master/tools) should have a common prefix, similarly to xc7frames2bit. I think this issue should only go as far as renaming the tools' names.

@nelsobe There should be no problem of leaving unmapped I/Os, if you are only interested in the synthesis step only. In case the tools complain about missing XDC file, you...

@nelsobe By default, at least for VPR, the I/O mapping happens similarly as any other block in the device, that is that it will be handled by the placer algorithm,...

@WhiteNinjaZ At the moment there is a PR which is soon-to-be-merged and open to add support for the MMCM primitives in [symbiflow-arch-defs](https://github.com/SymbiFlow/symbiflow-arch-defs/pull/1729). For context, symbiflow-arch-defs is the repository that generates...

@rodrigomelo9 It actually is expected it to be like that. - PCF: this type of constraints is only concerning placement of IOs, therefore it is required during `symbiflow_place` as the...

@mithro This is what is happening, the XDC contains all kinds of constraints including the placement ones. The yosys plugin can read the placement constraints and save them in the...

@mithro No. There are two independent flows concerning IO placement constraints, depending on what the user chooses: XDC flow: yosys parses the file and saves the constraints in the eblif....

Hi @WhiteNinjaZ, thanks for filing this. I believe this can be due to a bug in the [XDC yosys plugin](https://github.com/SymbiFlow/yosys-symbiflow-plugins/blob/5d91d446535d0ae349fbdb49a6a2867c9f7f41ef/xdc-plugin/xdc.cc#L142), causing the behaviour you see.

Hi @marcmerlin, I think that the problem here is that you did not source the conda environment, where `prjxray-config` is located. Another hint that this might be the case is...

@jhu960213 I believe that IBUF cells do not support any SLEW attribute indeed, and probably Vivado just ignores it. Here we define the extra attributes for the various IOs: https://github.com/SymbiFlow/symbiflow-arch-defs/blob/ef20acc081b620f3fbbf1d585360564e1ac789bc/xc/xc7/techmap/iobs.v#L1-L17,...