Tilegrid Fuzzer

This fuzzer creates the tilegrid.json bitstream database. This database contains segment definitions including base frame address and frame offsets.

Example workflow for CLB

generate.tcl LOCs one LUT per segment column towards generating frame base addresses.

A reference bitstream is generated and then:

  • a series of bitstreams are generated each with one LUT bit toggled; then

  • these are compared to find a toggled bit in the CLB segment column; then

  • the resulting address is truncated to get the base frame address.

Finally, generate.py calculates the segment word offsets based on known segment column structure

Environment variables


This environment variable must be set with a valid ROI. See database for example values


This environment variable must be set in case the part selected does not allow some tiles to be locked.

Error example (when using the artix 200T part): ERROR: [Place 30-25] Component carry4_SLICE_X82Y249 has been locked to a prohibited site SLICE_X82Y249.

To avoid this error, the XRAY_EXCLUDE_ROI_TILEGRID defines an ROI that is not taken into account when building the tilegrid, therefore excluding the problematic un-lockable sites.

As the resulting output file, tilegrid.json, is going to be checked against the one produced in the 074-dump_all fuzzer, also the latter one needs to produce a reduced tilegrid, with the excluded tiles specified with the environment variable.


This can be set to a specific value to speed up processing and reduce disk space If you don’t know where your ROI is, just set to to include all values (0x00000000:0xfffffff)


Optionally, use these as a small performance optimization:





These should, if unused, be set to -1, with this caveat:

WARNING: CLB test generates this based on CLBs but implicitly includes INT

Therefore, if you don’t set an explicit XRAY_ROI_GRID_* it may fail if you don’t have a CLB*_L at left and a CLB*_R at right.