Answers Database M1.4 CPLD - Timing violation: Slow simulation model produced with the "Use Local Macrocell Feedback" switch Record #3802 Product Family: Software Product Line: CPLD Implementation Product Part: CPLD Product Version: 1.4 Problem Title: M1.4 CPLD - Timing violation: Slow simulation model produced with the "Use Local Macrocell Feedback" switch Problem Description: Urgency: Standard Simulation model created slower than the correct model. Hold time errors reported when running design at slower clock rate than reported by the Timing Analyzer. The reported design should have run at 100Mhz, but gave timing violations at 20Mhz. The design simulated properly when the "Use Macrocell Feedback" switch is not being used. The patch referred to below solves this for M1.4. Solution 1: This problem is fixed in the latest M1.4 CPLD Tools Update available on the Xilinx Download Area: ftp://ftp.xilinx.com/pub/swhelp/M1.4_alliance/cpld_sol10_m14.tar.Z ftp://ftp.xilinx.com/pub/swhelp/M1.4_alliance/cpld_sun10_m14.tar.Z ftp://ftp.xilinx.com/pub/swhelp/M1.4_alliance/cpld_hp10_m14.tar.Z ftp://ftp.xilinx.com/pub/swhelp/M1.4_alliance/cpld_nt10_m14.zip These update files also include the changes from previous cpld updates. All zip files are created using WinZip. To obtain this utility, access WinZip's web site at http://www.winzip.com End of Record #3802 - Last Modified: 08/26/98 16:59

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