Yes, when the Error Detection (ED) CRC feature is enabled, it may cause the MLAB RAM blocks to operate incorrectly in Stratix® III devices. Only write operations in MLAB RAM blocks are affected. MLAB ROM blocks are not affected by this issue.
The ED CRC feature itself and CRC error flag operate correctly as expected. FPGA configuration bits are not affected by this issue.
Follow the recommended flow in Figure 1 to identify if your design is affected and to work around the problem.
Figure 1. Recommended Design Flow
For details on determining whether your design is affected and how to work around the problem, refer to Detailed Solution for Stratix III Error Detection (ED) CRC MLAB Issue (PDF).
You can download the script, patch, and related readme files using the links below:
- Download mlab_with_crc.tcl script to determine if your design uses ED CRC and MLAB RAMs
- Download Quartus® II software version 8.1 Patch 0.66 (Linux)
- Download Quartus II software version 8.1 Patch 0.66 (Windows)
- Download Quartus II software version 9.0 SP1 Patch 1.07 (Linux)
- Download Quartus II software version 9.0 SP1 Patch 1.07 (Windows)