What is the shortest pin-to-pin path through an XC7300 device, and how can this delay be achieved?
Solution
The fastest asynchronous path through an XC7300 device is tPDFO. This is the parameter being referenced when an XC7300 speed grade is specified.
tPDFO is the path from a fast input pin through one level of Fast Function Block logic to an output pin.
This path can be specified by flagging inputs as fast inputs (using the (FI) or .FI syntax in PLUSASM designs, or the F net attribute in schematic designs). The associated output pin should be assigned to a Fast Function Block if necessary, and cannot use more than 4 product terms when implemented as an active low equation.