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Development System Reference Guide www.xilinx.com 229
TRACE Reports
R
Report Legend
The following table lists descriptions of what X, R, and F mean in the data sheet report.
Note:
Applies to FPGA designs only.
Guaranteed Setup and Hold Reporting
Guaranteed setup and hold values obtained from speed files are used in the data sheet
reports for IOB input registers when these registers are clocked by specific clock routing
resources and when the guaranteed setup and hold times are available for a specified
device and speed.
Specific clock routing resources are clock networks that originate at a clock IOB, use a clock
buffer to reach a clock routing resource and route directly to IOB registers.
Guaranteed setup and hold times are also used for reporting of input OFFSET constraints.
The following figure and text describes the external setup and hold time relationships.
The pad CLKPAD of clock input component CLKIOB drives a global clock buffer
CLKBUF, which in turn drives an input flip-flop IFD. The input flip-flop IFD clocks a data
input driven from DATAPAD within the component IOB.
X Indeterminate
R Rising Edge
F Falling Edge
Figure 12-6: Guaranteed Setup and Hold
IOB
IFD
DATAPAD
CLKIOB
CLKPAD
CLKBUF
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