Quartus II Settings File Reference Manual - Altera

6–8 Chapter 6: Fitter Assignments
AUTO_C3_M9K_BIT_SKIP
AUTO_C3_M9K_BIT_SKIP
Type
Directs the Fitter to skip certain bitlines in Cyclone III (including LS) M9K blocks that
may be susceptible to read bit error when used in affected modes. The Standard
setting reserves the necessary M9K bitlines to ensure correct operation for all devices
within the selected temperature range. The Auto setting applies the necessary bitline
reservation to additional modes (×16 or ×18) to provide extra margin. The Maximum
setting applies the most conservative bitline reservation required for industrial
temperature ranges regardless of the targeted device settings. Enabling any of these
options can increase the number of M9K blocks required to implement the design.
You can override this global setting for each memory instance in the Assignment
Editor to customize the solution. Certain RAM modes may not be supported for
commercial temperature range devices when the Standard or Auto setting is applied.
The Fitter issues an error for these cases. You can implement RAM cells by making an
instance assignment with the Maximum setting, in which case additional M9K blocks
may be used. For more information, refer to the Cyclone III Device Family Errata Sheet.
Enumeration
■ Auto
■ Maximum
■ Off
■ Standard
Device Support
This setting can be used in projects targeting the following device families:
■ Cyclone III
■ Cyclone III LS
Notes
This assignment is included in the Fitter report.
Syntax
set_global_assignment -name AUTO_C3_M9K_BIT_SKIP
Default Value
Off
Quartus Settings File June 2012 Altera Corporation
Reference Manual