Article ID: 000078297 Content Type: Troubleshooting Last Reviewed: 09/14/2011

Mismatches Between Some Small ROM MATLAB and RTL Models

Environment

BUILT IN - ARTICLE INTRO SECOND COMPONENT

Critical Issue

Description

For the Small ROM architecture with a small Angular Resolution value and a large Magnitude Precision value, there can be mismatches between the outputs of the MATLAB model and the RTL. These mismatches are due to rounding differences.

Small ROM architecture of the NCO MegaCore function with a small Angular Resolution value and a large Magnitude Precision value.

The design impact is a comparison of the output values from the MATLAB model and RTL design during testing may show mismatches. However, the error margin is only /-1.

Resolution

To avoid this issue, modify your NCO MegaCore function in one of the following ways:

  • Set Angular Resolution to a large value.
  • Set Magnitude Precision to a small value.
  • Use a different architecture.

This issue will be fixed in a future version of the NCO MegaCore function.