Answers Database

XBLOX 5.x: internal error 20224, representation_error


Record #738

Product Family:  Software

Product Line:  FPGA Core

Problem Title:
XBLOX 5.x: internal error 20224, representation_error


Problem Description:
XBLOX may issue the following error on designs with very wide data paths.

   *** XBLOX: ERROR 20224:
	   INTERNAL ERROR
	   Please contact Xilinx Technical Support.  Please provide the
	   following details to the support personnel.	This information
	   will be needed by the software developers.
	   1. representation_error(is(_529,+(*(268435455,16),15)),2,
	   'integer overflow')

This can be caused by having binary counters with a COUNT_TO value of
greater than 31 bits.  XBLOX represents this COUNT_TO value as a signed
32-bit integer; therefore, the maximum COUNT_TO value is 2^31-1.


Solution 1:

As a workaround, cascade two half-sized COUNTERs.  Although this provides a
valid solution, please note that this does reduces the performance somewhat
(especially in XC4000 designs), due to the break in the carry chain.



End of Record #738