Board file (XML) and Constraints file (XDC) in Vivado

[Twoism]

Hi,
I'm not able to fully understand the relation between the Board file and the Constraints file in Vivado. In my design I need to connect a custom IP block to a Pmod connector on a ZYBO board. I've loaded the XML board file provided by Digilent but now I'm not anymore able to customize the pins as i would do with a constraint file since it seem to me that the mapping it is now specified in the XML file.

# Pmod connector JB
set_property PACKAGE_PIN T20 [get_ports {d_out[0]}]
set_property PACKAGE_PIN U20 [get_ports {d_out[1]}]
set_property PACKAGE_PIN V20 [get_ports {d_out[2]}]
set_property PACKAGE_PIN W20 [get_ports {d_out[3]}]
set_property IOSTANDARD LVCMOS33 [get_ports {d_out[*]}]

Should I need to add a constraint file even if the Board port mapping is already specified by the board file? Is this a good practice?

Thanks
 

[jpeyron]

Hi Twoism,

You would still need to use the xdc to assign the Pmod. They are not included in the board files. You will have to add the xdc file for the constraints of the Pmods.

thank you,

 

Jon 

[bklopp]

I assumed the constraints were generated from the pin file, which is referenced by the board file.

[jpeyron]

Hi @bklopp,

The Pmod Ports are in the board files and are usable by the Pmod IP Cores that are in the Vivado Library here. Here is a tutorial that shows how to use the Pmod IP Cores. Since twoism was using a custom IP Core to connect to the Pmod Port they would have need to use the xdc to constrain the pins.

thank you,

Jon