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AR# 65574

Vivado 2015.2 UltraScale HSTL Class I: Default OUTPUT_IMPEDENCE & ODT combination setting is incorrect


(UG571) Table 1-37 lists the allowed combination of the OUTPUT_IMPEDENCE & ODT attributes for HSTL Class I bidirectional I/Os.

The only allowed use of the 48 ohm driver impedance, RDRV_48_48, is when ODT is set to either RTT_NONE or RTT_48.

However, by default the Tool picks up RDRV_48_48 & RTT_40 for bidirectional HSTL class I I/Os.


To work around this issue, set the OUTPUT_IMPEDENCE & ODT attributes to a valid combination as per the table above.

AR# 65574
Date Created 10/06/2015
Last Updated 02/02/2016
Status Active
Type General Article
  • Virtex UltraScale
  • Kintex UltraScale
  • Vivado Design Suite - 2015.2