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AR# 4823

12.1 Timing - How are the setup and hold times calculated for the data sheet I/O report?

Description

How are the setup and hold values calculated for the data sheet I/O report?

External Setup and Hold
External Setup and Hold

解决方案

Setup times

The external setup time is defined as the setup time of the DATAPAD within the IOB, relative to the CLKPAD within the CLKIOB.

When a guaranteed external setup time exists in the speed files for a particular DATAPAD and CLKPAD pair and configuration, this number will be utilized in timing reports. When no guaranteed external setup time exists in the speed files for a particular DATAPAD and CLKPAD pair, the external setup time will be reported as the maximum path delay from DATAPAD to the IFD, plus the maximum IFD setup time, minus the minimum of maximum path delay(s) from the CLKPAD to the IFD.

Hold times

The external hold time is defined as the hold time of the DATAPAD within the IOB, relative to the CLKPAD within the CLKIOB.

When a guaranteed external hold time exists in the speed files for a particular DATAPAD and CLKPAD pair and configuration, this number will be utilized in timing reports. When no guaranteed external hold time exists in the speed files for a particular DATAPAD and CLKPAD pair, the external hold time will be reported as the maximum path delay from CLKPAD to the IFD, plus the maximum IFD hold time, minus the minimum of maximum path delay(s) from the DATAPAD to the IFD.

AR# 4823
创建日期 08/21/2007
Last Updated 12/15/2012
状态 Active
Type 综合文章