Critical Issue
M4K block write operations may fail for Cyclone II devices with the Alpha Blending Mixer and Gamma Corrector MegaCore functions.
This issue affects configurations using Cyclone II devices and the Alpha Blending Mixer or Gamma Corrector MegaCore function.
The Quartus II software issues the following error message:
Error: M4K memory block WYSIWYG primitive "vhdl_gam:vhdl_gam_inst|TTA_X_smem_av:gamma_lut|altsyncram:\ds1:altsyncram_component|altsyncram_rvh1:auto_generated|ram_block1a0"
utilizes the dual-port dual-clock mode. However, this mode is not
supported in Cyclone II device family in this version of Quartus
II software. Please refer to the Cyclone II FPGA Family Errata Sheet
for more information on this feature.
If you target any affected revision (Rev a or b of the 2c35
or Rev a of any other Cyclone II part), set the CYCLONEII_SAFE_WRITE variable
to RESTRUCTURE. This setting causes the Quartus II
software to fix the issue at a cost in M4Ks and Fmax.
If you are using a newer revision device, set the CYCLONEII_SAFE_WRITE variable
to VERIFIED_SAFE, which turns off the error message.
This issue is fixed for the latest silicon devices but remains an issue if you are using the earlier silicon.
Refer to the Cyclone II FPGA Family Errata Sheet for more information about this issue.