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AR# 63612

MIG UltraScale - How to determine tap resolution using XSDB registers or the MIG debug GUI.


The read and write window sizes are provided as a number of taps through the MIG debug GUI or by reading the XSDB registers. 

For information on how to determine the read and write windows, please see (Xilinx Answer 60305).

Is it possible to determine the tap resolution and convert the windows size specified in number of taps to the actual ps size?


It is possible to determine the window size in ps by first calculating the tap resolution and then multiplying the resolution by the number of taps found in the read/write window.  

The tap resolution will vary across processes (down to each nibble within a part).  

However, within a specific process, each tap within the delay chain has the same precise resolution.

  • To compute the 90 degree offset in taps, take (BISC_PQTR - BISC_ALIGN_PQTR)
  • To estimate tap resolution, take (1/4 of the memory clock period)/ (BISC_PQTR - BISC_ALIGN_PQTR)
  • The same then applies for NQTR

BISC is not run for the write side. 

Therefore, we use the resolution found on the read as an estimate of the write.

AR# 63612
Date Created 02/18/2015
Last Updated 03/12/2015
Status Active
Type Known Issues
  • Kintex UltraScale
  • Virtex UltraScale
  • MIG UltraScale