The OUTPUT_IMPEDANCE attribute provides the option of choosing the driver impedance for HSTL, SSTL, HSUL, LVDCI, HSLVDCI, and POD drivers to match the characteristic impedance of the driven line. The OUTPUT_IMPEDANCE attribute is used to define the value of source termination at the driver for both DCI and non-DCI versions of the standards supported.
Allowed values for the OUTPUT_IMPEDANCE attribute:
Note: Not all values are allowed for all applicable I/O standards and configurations.
The XDC syntax for this attribute is:
set_property OUTPUT_IMPEDANCE value [get_ports port_name]